fixed metadata hooks

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

.gitea/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,18 @@
+---
+name: Bug report
+about: For reporting bugs in micro
+title: "[BUG]"
+labels: ''
+assignees: ''
+
+---
+
+**Describe the bug**
+
+1. What are you trying to do?
+2. What did you expect to happen?
+3. What happens instead?
+
+**How to reproduce the bug:**
+
+If possible, please include a minimal code snippet here.

.gitea/ISSUE_TEMPLATE/feature-request---enhancement.md

@@ -0,0 +1,17 @@
+---
+name: Feature request / Enhancement
+about: If you have a need not served by micro
+title: "[FEATURE]"
+labels: ''
+assignees: ''
+
+---
+
+**Is your feature request related to a problem? Please describe.**
+A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+
+**Describe the solution you'd like**
+A clear and concise description of what you want to happen.
+
+**Additional context**
+Add any other context or screenshots about the feature request here.

.gitea/ISSUE_TEMPLATE/question.md

@@ -0,0 +1,8 @@
+---
+name: Question
+about: Ask a question about micro
+title: ''
+labels: ''
+assignees: ''
+
+---

.gitea/autoapprove.yml

@@ -0,0 +1,28 @@
+name: "autoapprove"
+
+on:
+  pull_request_target:
+    types: [assigned, opened, synchronize, reopened]
+  workflow_run:
+    workflows: ["prbuild"]
+    types:
+      - completed
+
+permissions:
+  pull-requests: write
+  contents: write
+
+jobs:
+  autoapprove:
+    runs-on: ubuntu-latest
+    steps:
+      - name: approve
+        run: [ "curl -o tea https://dl.gitea.com/tea/main/tea-main-linux-amd64",
+               "chmod +x ./tea",
+               "./tea login add --name unistack --token ${{ secrets.GITHUB_TOKEN }} --url https://git.unistack.org",
+               "./tea pr --repo ${{ github.event.repository.name }}"
+        ]
+        if: github.actor == 'vtolstov'
+        id: approve
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}

.gitea/workflows/job_coverage.yml

@@ -0,0 +1,54 @@
+name: coverage
+
+on:
+  push:
+    branches: [ main, v3, v4 ]
+    paths-ignore:
+      - '.github/**'
+      - '.gitea/**'
+  pull_request:
+    branches: [ main, v3, v4 ]
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+jobs:
+
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - name: checkout code
+      uses: actions/checkout@v4
+      with:
+        filter: 'blob:none'
+
+    - name: setup go
+      uses: actions/setup-go@v5
+      with:
+        cache-dependency-path: "**/*.sum"
+        go-version: 'stable' 
+
+    - name: test coverage
+      run: |
+        go test -v -cover ./... -covermode=count -coverprofile coverage.out -coverpkg ./...
+        go tool cover -func coverage.out -o coverage.out
+
+    - name: coverage badge
+      uses: tj-actions/coverage-badge-go@v2
+      with:
+        green: 80
+        filename: coverage.out
+
+    - uses: stefanzweifel/git-auto-commit-action@v4
+      name: autocommit
+      with:
+        commit_message: Apply Code Coverage Badge
+        skip_fetch: true
+        skip_checkout: true
+        file_pattern: ./README.md
+
+    - name: push
+      if: steps.auto-commit-action.outputs.changes_detected == 'true'
+      uses: ad-m/github-push-action@master
+      with:
+        github_token: ${{ github.token }}
+        branch: ${{ github.ref }}

.gitea/workflows/job_lint.yml

@@ -0,0 +1,29 @@
+name: lint
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+    branches: [ master, v3, v4 ]
+    paths-ignore:
+      - '.github/**'
+      - '.gitea/**'
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+    - name: checkout code
+      uses: actions/checkout@v4
+      with:
+        filter: 'blob:none'
+    - name: setup go
+      uses: actions/setup-go@v5
+      with:
+        cache-dependency-path: "**/*.sum"
+        go-version: 'stable' 
+    - name: setup deps
+      run: go get -v ./...
+    - name: run lint
+      uses: https://github.com/golangci/golangci-lint-action@v6
+      with:
+        version: 'latest'

.gitea/workflows/job_syncpull.yml

@@ -0,0 +1,54 @@
+name: syncpull
+
+on:
+  schedule:
+    - cron: '* * * * *'
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+jobs:
+  pull:
+    runs-on: ubuntu-latest
+    steps:
+    - name: init
+      run: |
+        git config --global user.email "vtolstov <vtolstov@users.noreply.github.com>"
+        git config --global user.name "github-actions[bot]"
+        echo "machine git.unistack.org login vtolstov password ${{ secrets.TOKEN_GITEA }}" | tee -a /root/.netrc
+        echo "machine github.com login vtolstov password ${{ secrets.TOKEN_GITHUB }}" | tee -a /root/.netrc
+
+    - name: track master
+      run: |
+        git clone --depth=10 --branch master --single-branch ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY} repo
+        cd repo
+        git remote add --no-tags --fetch --track master upstream https://github.com/${GITHUB_REPOSITORY}
+        git pull --rebase upstream master
+        git push upstream master --progress
+        git merge --allow-unrelated-histories "upstream/master"
+        git push origin master --progress
+        cd ../
+        rm -rf repo
+
+    - name: track v3
+      run: |
+        git clone --depth=10 --branch v3 --single-branch ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY} repo
+        cd repo
+        git remote add --no-tags --fetch --track v3 upstream https://github.com/${GITHUB_REPOSITORY}
+        git pull --rebase upstream v3
+        git push upstream v3
+        git merge --allow-unrelated-histories "upstream/v3"
+        git push origin v3 --progress
+        cd ../
+        rm -rf repo
+
+    - name: track v4
+      run: |
+        git clone --depth=10 --branch v4 --single-branch ${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY} repo
+        cd repo
+        git remote add --no-tags --fetch --track v4 upstream https://github.com/${GITHUB_REPOSITORY}
+        git pull --rebase upstream v4
+        git push upstream v4
+        git merge --allow-unrelated-histories "upstream/v4"
+        git push origin v4 --progress
+        cd ../
+        rm -rf repo

.gitea/workflows/job_test.yml

@@ -0,0 +1,31 @@
+name: test
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+    branches: [ master, v3, v4 ]
+  push:
+    branches: [ master, v3, v4 ]
+    paths-ignore:
+      - '.github/**'
+      - '.gitea/**'
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - name: checkout code
+      uses: actions/checkout@v4
+      with:
+        filter: 'blob:none'
+    - name: setup go
+      uses: actions/setup-go@v5
+      with:
+        cache-dependency-path: "**/*.sum"
+        go-version: 'stable'
+    - name: setup deps
+      run: go get -v ./...
+    - name: run test
+      env:
+        INTEGRATION_TESTS: yes
+      run: go test -mod readonly -v ./...

.gitea/workflows/job_tests.yml

@@ -0,0 +1,50 @@
+name: test
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+    branches: [ master, v3, v4 ]
+  push:
+    branches: [ master, v3, v4 ]
+    paths-ignore:
+      - '.github/**'
+      - '.gitea/**'
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - name: checkout code
+      uses: actions/checkout@v4
+      with:
+        filter: 'blob:none'
+    - name: checkout tests
+      uses: actions/checkout@v4
+      with:
+        ref: master
+        filter: 'blob:none'
+        repository: unistack-org/micro-tests
+        path: micro-tests
+    - name: setup go
+      uses: actions/setup-go@v5
+      with:
+        cache-dependency-path: "**/*.sum"
+        go-version: 'stable'
+    - name: setup go work
+      env:
+        GOWORK: /workspace/${{ github.repository_owner }}/go.work
+      run: |
+        go work init
+        go work use .
+        go work use micro-tests
+    - name: setup deps
+      env:
+        GOWORK: /workspace/${{ github.repository_owner }}/go.work
+      run: go get -v ./...
+    - name: run tests
+      env:
+        INTEGRATION_TESTS: yes
+        GOWORK: /workspace/${{ github.repository_owner }}/go.work
+      run: |
+        cd micro-tests
+        go test -mod readonly -v ./... || true

.github.old/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,9 @@
+## Pull Request template
+Please, go through these steps before clicking submit on this PR.
+
+1. Give a descriptive title to your PR.
+2. Provide a description of your changes.
+3. Make sure you have some relevant tests.
+4. Put `closes #XXXX` in your comment to auto-close the issue that your PR fixes (if applicable).
+
+**PLEASE REMOVE THIS TEMPLATE BEFORE SUBMITTING**

.github.old/dependabot.yml

@@ -11,9 +11,16 @@ updates:
     directory: "/"
     schedule:
       interval: "daily"
+    commit-message:
+      prefix: "chore"
+      include: "scope"
 
   # Maintain dependencies for Golang
   - package-ecosystem: "gomod"
     directory: "/"
     schedule:
       interval: "daily"
+    commit-message:
+      prefix: "chore"
+      include: "scope"
+

.github.old/workflows/autoapprove.yml

@@ -0,0 +1,24 @@
+name: "autoapprove"
+
+on:
+  pull_request_target:
+    types: [assigned, opened, synchronize, reopened]
+  workflow_run:
+    workflows: ["prbuild"]
+    types:
+      - completed
+
+permissions:
+  pull-requests: write
+  contents: write
+
+jobs:
+  autoapprove:
+    runs-on: ubuntu-latest
+    steps:
+      - name: approve
+        uses: hmarr/auto-approve-action@v3
+        if: github.actor == 'vtolstov' || github.actor == 'dependabot[bot]'
+        id: approve
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}

.github.old/workflows/automerge.yml

@@ -0,0 +1,21 @@
+name: "automerge"
+
+on:
+  pull_request_target:
+    types: [assigned, opened, synchronize, reopened]
+
+permissions:
+  pull-requests: write
+  contents: write
+
+jobs:
+  automerge:
+    runs-on: ubuntu-latest
+    if: github.actor == 'vtolstov'
+    steps:
+      - name: merge
+        id: merge
+        run: gh pr merge --auto --merge "$PR_URL"
+        env:
+          PR_URL: ${{github.event.pull_request.html_url}}
+          GITHUB_TOKEN: ${{secrets.TOKEN}}

.github.old/workflows/build.yml

@@ -1,59 +1,44 @@
 name: build
 on:
-  push:
+ push:
     branches:
     - master
+    - v3
 jobs:
   test:
     name: test
     runs-on: ubuntu-latest
     steps:
     - name: setup
-      uses: actions/setup-go@v2
+      uses: actions/setup-go@v3
       with:
-        go-version: 1.16
+        go-version: 1.17
+    - name: checkout
+      uses: actions/checkout@v3
     - name: cache
-      uses: actions/cache@v2
+      uses: actions/cache@v3
       with:
         path: ~/go/pkg/mod
         key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
         restore-keys: ${{ runner.os }}-go-
-    - name: sdk checkout
-      uses: actions/checkout@v2
-    - name: sdk deps
+    - name: deps
       run: go get -v -t -d ./...
-    - name: sdk test
+    - name: test
       env:
         INTEGRATION_TESTS: yes
       run: go test -mod readonly -v ./...
-    - name: tests checkout
-      uses: actions/checkout@v2
-      with:
-        repository: unistack-org/micro-tests
-        ref: refs/heads/master
-        path: micro-tests
-        fetch-depth: 1
-    - name: tests deps
-      run: |
-        cd micro-tests
-        go mod edit -replace="github.com/unistack-org/micro/v3=../"
-        go get -v -t -d ./...
-    - name: tests test
-      env:
-        INTEGRATION_TESTS: yes
-      run: cd micro-tests && go test -mod readonly -v ./...
   lint:
     name: lint
     runs-on: ubuntu-latest
     steps:
       - name: checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: lint
-        uses: golangci/golangci-lint-action@v2
+        uses: golangci/golangci-lint-action@v3.4.0
         continue-on-error: true
         with:
           # Required: the version of golangci-lint is required and must be specified without patch version: we always use the latest patch version.
-          version: v1.39
+          version: v1.30
           # Optional: working directory, useful for monorepos
           # working-directory: somedir
           # Optional: golangci-lint command line arguments.

.github.old/workflows/codecov.yml

@@ -0,0 +1,39 @@
+name: "codecov"
+
+on:
+  workflow_run:
+    workflows: ["build"]
+    types:
+      - completed
+  push:
+    branches: [ v3 ]
+  pull_request:
+    branches: [ v3 ]
+  schedule:
+    - cron: '34 1 * * 0'
+
+jobs:
+  codecov:
+    name: codecov
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ 'go' ]
+
+    steps:
+    - name: checkout
+      uses: actions/checkout@v3
+    - name: setup
+      uses: actions/setup-go@v3
+      with:
+        go-version: 1.17
+    - name: Run coverage
+      run: go test -v -race -coverprofile=coverage.out -covermode=atomic ./...
+    - name: codecov
+      uses: codecov/codecov-action@v3.1.1

.github.old/workflows/codeql-analysis.yml

@@ -0,0 +1,78 @@
+# For most projects, this workflow file will not need changing; you simply need
+# to commit it to your repository.
+#
+# You may wish to alter this file to override the set of languages analyzed,
+# or to provide custom queries or build logic.
+#
+# ******** NOTE ********
+# We have attempted to detect the languages in your repository. Please check
+# the `language` matrix defined below to confirm you have the correct set of
+# supported CodeQL languages.
+#
+name: "codeql"
+
+on:
+  workflow_run:
+    workflows: ["prbuild"]
+    types:
+      - completed
+  push:
+    branches: [ master, v3 ]
+  pull_request:
+    # The branches below must be a subset of the branches above
+    branches: [ master, v3 ]
+  schedule:
+    - cron: '34 1 * * 0'
+
+jobs:
+  analyze:
+    name: analyze
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ 'go' ]
+        # CodeQL supports [ 'cpp', 'csharp', 'go', 'java', 'javascript', 'python' ]
+        # Learn more:
+        # https://docs.github.com/en/free-pro-team@latest/github/finding-security-vulnerabilities-and-errors-in-your-code/configuring-code-scanning#changing-the-languages-that-are-analyzed
+
+    steps:
+    - name: checkout
+      uses: actions/checkout@v3
+    - name: setup
+      uses: actions/setup-go@v3
+      with:
+        go-version: 1.17
+    # Initializes the CodeQL tools for scanning.
+    - name: init
+      uses: github/codeql-action/init@v2
+      with:
+        languages: ${{ matrix.language }}
+        # If you wish to specify custom queries, you can do so here or in a config file.
+        # By default, queries listed here will override any specified in a config file.
+        # Prefix the list here with "+" to use these queries and those in the config file.
+        # queries: ./path/to/local/query, your-org/your-repo/queries@main
+
+    # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
+    # If this step fails, then you should remove it and run the build manually (see below)
+    - name: autobuild
+      uses: github/codeql-action/autobuild@v2
+
+    # ℹ️ Command-line programs to run using the OS shell.
+    # 📚 https://git.io/JvXDl
+
+    # ✏️ If the Autobuild fails above, remove it and uncomment the following three lines
+    #    and modify them (or add more) to build your code if your project
+    #    uses a compiled language
+
+    #- run: |
+    #   make bootstrap
+    #   make release
+
+    - name: analyze
+      uses: github/codeql-action/analyze@v2

.github.old/workflows/dependabot-automerge.yml

@@ -0,0 +1,27 @@
+name: "dependabot-automerge"
+
+on:
+  pull_request_target:
+    types: [assigned, opened, synchronize, reopened]
+
+permissions:
+  pull-requests: write
+  contents: write
+
+jobs:
+  automerge:
+    runs-on: ubuntu-latest
+    if: github.actor == 'dependabot[bot]'
+    steps:
+      - name: metadata
+        id: metadata
+        uses: dependabot/fetch-metadata@v1.3.6
+        with:
+          github-token: "${{ secrets.TOKEN }}"
+      - name: merge
+        id: merge
+        if: ${{contains(steps.metadata.outputs.dependency-names, 'go.unistack.org')}}
+        run: gh pr merge --auto --merge "$PR_URL"
+        env:
+          PR_URL: ${{github.event.pull_request.html_url}}
+          GITHUB_TOKEN: ${{secrets.TOKEN}}

.github.old/workflows/pr.yml

@@ -0,0 +1,40 @@
+name: prbuild
+on:
+  pull_request:
+    branches:
+    - master
+    - v3
+jobs:
+  test:
+    name: test
+    runs-on: ubuntu-latest
+    steps:
+    - name: setup
+      uses: actions/setup-go@v3
+      with:
+        go-version: 1.17
+    - name: checkout
+      uses: actions/checkout@v3
+    - name: cache
+      uses: actions/cache@v3
+      with:
+        path: ~/go/pkg/mod
+        key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
+        restore-keys: ${{ runner.os }}-go-
+    - name: deps
+      run: go get -v -t -d ./...
+    - name: test
+      env:
+        INTEGRATION_TESTS: yes
+      run: go test -mod readonly -v ./...
+  lint:
+    name: lint
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout
+        uses: actions/checkout@v3
+      - name: lint
+        uses: golangci/golangci-lint-action@v3.4.0
+        continue-on-error: true
+        with:
+          version: v1.30

.github/workflows/pr.yml

@@ -1,62 +0,0 @@
-name: prbuild
-on:
-  pull_request:
-    branches:
-    - master
-jobs:
-  test:
-    name: test
-    runs-on: ubuntu-latest
-    steps:
-    - name: setup
-      uses: actions/setup-go@v2
-      with:
-        go-version: 1.16
-    - name: cache
-      uses: actions/cache@v2
-      with:
-        path: ~/go/pkg
-        key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
-        restore-keys: ${{ runner.os }}-go-
-    - name: sdk checkout
-      uses: actions/checkout@v2
-    - name: sdk deps
-      run: go get -v -t -d ./...
-    - name: sdk test
-      env:
-        INTEGRATION_TESTS: yes
-      run: go test -mod readonly -v ./...
-    - name: tests checkout
-      uses: actions/checkout@v2
-      with:
-        repository: unistack-org/micro-tests
-        ref: refs/heads/master
-        path: micro-tests
-        fetch-depth: 1
-    - name: tests deps
-      run: |
-        cd micro-tests
-        go mod edit -replace="github.com/unistack-org/micro/v3=../"
-        go get -v -t -d ./...
-    - name: tests test
-      env:
-        INTEGRATION_TESTS: yes
-      run: cd micro-tests && go test -mod readonly -v ./...
-  lint:
-    name: lint
-    runs-on: ubuntu-latest
-    steps:
-      - name: checkout
-        uses: actions/checkout@v2
-      - name: lint
-        uses: golangci/golangci-lint-action@v2
-        continue-on-error: true
-        with:
-          # Required: the version of golangci-lint is required and must be specified without patch version: we always use the latest patch version.
-          version: v1.39
-          # Optional: working directory, useful for monorepos
-          # working-directory: somedir
-          # Optional: golangci-lint command line arguments.
-          # args: --issues-exit-code=0
-          # Optional: show only new issues if it's a pull request. The default value is `false`.
-          # only-new-issues: true

.gitignore

@@ -1,6 +1,8 @@
 # Develop tools
 /.vscode/
 /.idea/
+.idea
+.vscode
 
 # Binaries for programs and plugins
 *.exe
@@ -13,6 +15,7 @@
 _obj
 _test
 _build
+.DS_Store
 
 # Architecture specific extensions/prefixes
 *.[568vq]

.golangci.yml

@@ -1,44 +1,5 @@
 run:
-  concurrency: 4
+  concurrency: 8
   deadline: 5m
   issues-exit-code: 1
   tests: true
-
-linters-settings:
-  govet:
-    check-shadowing: true
-    enable:
-      - fieldalignment
-
-linters:
-  enable:
-    - govet
-    - deadcode
-    - errcheck
-    - govet
-    - ineffassign
-    - staticcheck
-    - structcheck
-    - typecheck
-    - unused
-    - varcheck
-    - bodyclose
-    - gci
-    - goconst
-    - gocritic
-    - gosimple
-    - gofmt
-    - gofumpt
-    - goimports
-    - golint
-    - gosec
-    - makezero
-    - misspell
-    - nakedret
-    - nestif
-    - nilerr
-    - noctx
-    - prealloc
-    - unconvert
-    - unparam
-  disable-all: false

README.md

@@ -1,4 +1,9 @@
-# Micro [![License](https://img.shields.io/:license-apache-blue.svg)](https://opensource.org/licenses/Apache-2.0) [![Doc](https://img.shields.io/badge/go.dev-reference-007d9c?logo=go&logoColor=white&style=flat-square)](https://pkg.go.dev/github.com/unistack-org/micro/v3?tab=overview) [![Status](https://github.com/unistack-org/micro/workflows/build/badge.svg?branch=master)](https://github.com/unistack-org/micro/actions?query=workflow%3Abuild+branch%3Amaster+event%3Apush) [![Lint](https://goreportcard.com/badge/github.com/unistack-org/micro)](https://goreportcard.com/report/github.com/unistack-org/micro) [![Slack](https://img.shields.io/static/v1?label=micro&message=slack&color=blueviolet)](https://unistack-org.slack.com/messages/default)
+# Micro
+![Coverage](https://img.shields.io/badge/Coverage-46.4%25-yellow)
+[![License](https://img.shields.io/:license-apache-blue.svg)](https://opensource.org/licenses/Apache-2.0)
+[![Doc](https://img.shields.io/badge/go.dev-reference-007d9c?logo=go&logoColor=white&style=flat-square)](https://pkg.go.dev/go.unistack.org/micro/v4?tab=overview)
+[![Status](https://git.unistack.org/unistack-org/micro/actions/workflows/job_tests.yml/badge.svg?branch=v4)](https://git.unistack.org/unistack-org/micro/actions?query=workflow%3Abuild+branch%3Av4+event%3Apush)
+[![Lint](https://goreportcard.com/badge/go.unistack.org/micro/v4)](https://goreportcard.com/report/go.unistack.org/micro/v4)
 
 Micro is a standard library for microservices.
 
@@ -10,30 +15,20 @@ Micro provides the core requirements for distributed systems development includi
 
 Micro abstracts away the details of distributed systems. Here are the main features.
 
-- **Authentication** - Auth is built in as a first class citizen. Authentication and authorization enable secure 
-zero trust networking by providing every service an identity and certificates. This additionally includes rule 
-based access control.
-
 - **Dynamic Config** - Load and hot reload dynamic config from anywhere. The config interface provides a way to load application 
-level config from any source such as env vars, file, etcd. You can merge the sources and even define fallbacks.
+level config from any source such as env vars, cmdline, file, consul, vault... You can merge the sources and even define fallbacks.
 
 - **Data Storage** - A simple data store interface to read, write and delete records. It includes support for memory, file and 
-CockroachDB by default. State and persistence becomes a core requirement beyond prototyping and Micro looks to build that into the framework.
+s3. State and persistence becomes a core requirement beyond prototyping and Micro looks to build that into the framework.
 
 - **Service Discovery** - Automatic service registration and name resolution. Service discovery is at the core of micro service 
 development. When service A needs to speak to service B it needs the location of that service.
 
-- **Load Balancing** - Client side load balancing built on service discovery. Once we have the addresses of any number of instances 
-of a service we now need a way to decide which node to route to. We use random hashed load balancing to provide even distribution 
-across the services and retry a different node if there's a problem. 
-
 - **Message Encoding** - Dynamic message encoding based on content-type. The client and server will use codecs along with content-type 
 to seamlessly encode and decode Go types for you. Any variety of messages could be encoded and sent from different clients. The client 
 and server handle this by default.
 
-- **Transport** - gRPC or http based request/response with support for bidirectional streaming. We provide an abstraction for synchronous communication. A request made to a service will be automatically resolved, load balanced, dialled and streamed.
-
-- **Async Messaging** - PubSub is built in as a first class citizen for asynchronous communication and event driven architectures.
+- **Async Messaging** - Pub/Sub is built in as a first class citizen for asynchronous communication and event driven architectures.
 Event notifications are a core pattern in micro service development.
 
 - **Synchronization** - Distributed systems are often built in an eventually consistent manner. Support for distributed locking and 
@@ -42,10 +37,6 @@ leadership are built in as a Sync interface. When using an eventually consistent
 - **Pluggable Interfaces** - Micro makes use of Go interfaces for each system abstraction. Because of this these interfaces 
 are pluggable and allows Micro to be runtime agnostic.
 
-## Getting Started
-
-To be created.
-
 ## License
 
 Micro is Apache 2.0 licensed.

api/api.go

@@ -1,181 +0,0 @@
-package api
-
-import (
-	"errors"
-	"regexp"
-	"strings"
-
-	"github.com/unistack-org/micro/v3/metadata"
-	"github.com/unistack-org/micro/v3/register"
-	"github.com/unistack-org/micro/v3/server"
-)
-
-// Api interface
-type Api interface {
-	// Initialise options
-	Init(...Option) error
-	// Get the options
-	Options() Options
-	// Register a http handler
-	Register(*Endpoint) error
-	// Register a route
-	Deregister(*Endpoint) error
-	// Implementation of api
-	String() string
-}
-
-// Options holds the options
-type Options struct{}
-
-// Option func signature
-type Option func(*Options) error
-
-// Endpoint is a mapping between an RPC method and HTTP endpoint
-type Endpoint struct {
-	// Name Greeter.Hello
-	Name string
-	// Desciption for endpoint
-	Description string
-	// Handler e.g rpc, proxy
-	Handler string
-	// Body destination
-	// "*" or "" - top level message value
-	// "string" - inner message value
-	Body string
-	// Host e.g example.com
-	Host []string
-	// Method e.g GET, POST
-	Method []string
-	// Path e.g /greeter. Expect POSIX regex
-	Path []string
-	// Stream flag
-	Stream bool
-}
-
-// Service represents an API service
-type Service struct {
-	// Name of service
-	Name string
-	// Endpoint for this service
-	Endpoint *Endpoint
-	// Services that provides service
-	Services []*register.Service
-}
-
-// Encode encodes an endpoint to endpoint metadata
-func Encode(e *Endpoint) map[string]string {
-	if e == nil {
-		return nil
-	}
-
-	// endpoint map
-	ep := make(map[string]string)
-
-	// set vals only if they exist
-	set := func(k, v string) {
-		if len(v) == 0 {
-			return
-		}
-		ep[k] = v
-	}
-
-	set("endpoint", e.Name)
-	set("description", e.Description)
-	set("handler", e.Handler)
-	set("method", strings.Join(e.Method, ","))
-	set("path", strings.Join(e.Path, ","))
-	set("host", strings.Join(e.Host, ","))
-	set("body", e.Body)
-
-	return ep
-}
-
-// Decode decodes endpoint metadata into an endpoint
-func Decode(e metadata.Metadata) *Endpoint {
-	if e == nil {
-		return nil
-	}
-
-	ep := &Endpoint{}
-	ep.Name, _ = e.Get("endpoint")
-	ep.Description, _ = e.Get("description")
-	epmethod, _ := e.Get("method")
-	ep.Method = []string{epmethod}
-	eppath, _ := e.Get("path")
-	ep.Path = []string{eppath}
-	ephost, _ := e.Get("host")
-	ep.Host = []string{ephost}
-	ep.Handler, _ = e.Get("handler")
-	ep.Body, _ = e.Get("body")
-
-	return ep
-}
-
-// Validate validates an endpoint to guarantee it won't blow up when being served
-func Validate(e *Endpoint) error {
-	if e == nil {
-		return errors.New("endpoint is nil")
-	}
-
-	if len(e.Name) == 0 {
-		return errors.New("name required")
-	}
-
-	for _, p := range e.Path {
-		ps := p[0]
-		pe := p[len(p)-1]
-
-		if ps == '^' && pe == '$' {
-			_, err := regexp.CompilePOSIX(p)
-			if err != nil {
-				return err
-			}
-		} else if ps == '^' && pe != '$' {
-			return errors.New("invalid path")
-		} else if ps != '^' && pe == '$' {
-			return errors.New("invalid path")
-		}
-	}
-
-	if len(e.Handler) == 0 {
-		return errors.New("invalid handler")
-	}
-
-	return nil
-}
-
-/*
-Design ideas
-
-// Gateway is an api gateway interface
-type Gateway interface {
-	// Register a http handler
-	Handle(pattern string, http.Handler)
-	// Register a route
-	RegisterRoute(r Route)
-	// Init initialises the command line.
-	// It also parses further options.
-	Init(...Option) error
-	// Run the gateway
-	Run() error
-}
-
-// NewGateway returns a new api gateway
-func NewGateway() Gateway {
-	return newGateway()
-}
-*/
-
-// WithEndpoint returns a server.HandlerOption with endpoint metadata set
-//
-// Usage:
-//
-// 	proto.RegisterHandler(service.Server(), new(Handler), api.WithEndpoint(
-//		&api.Endpoint{
-//			Name: "Greeter.Hello",
-//			Path: []string{"/greeter"},
-//		},
-//	))
-func WithEndpoint(e *Endpoint) server.HandlerOption {
-	return server.EndpointMetadata(e.Name, Encode(e))
-}

api/api_test.go

@@ -1,152 +0,0 @@
-package api
-
-import (
-	"strings"
-	"testing"
-)
-
-//nolint:gocyclo
-func TestEncoding(t *testing.T) {
-	testData := []*Endpoint{
-		nil,
-		{
-			Name:        "Foo.Bar",
-			Description: "A test endpoint",
-			Handler:     "meta",
-			Host:        []string{"foo.com"},
-			Method:      []string{"GET"},
-			Path:        []string{"/test"},
-		},
-	}
-
-	compare := func(expect, got []string) bool {
-		// no data to compare, return true
-		if len(expect) == 0 && len(got) == 0 {
-			return true
-		}
-		// no data expected but got some return false
-		if len(expect) == 0 && len(got) > 0 {
-			return false
-		}
-
-		// compare expected with what we got
-		for _, e := range expect {
-			var seen bool
-			for _, g := range got {
-				if e == g {
-					seen = true
-					break
-				}
-			}
-			if !seen {
-				return false
-			}
-		}
-
-		// we're done, return true
-		return true
-	}
-
-	for _, d := range testData {
-		// encode
-		e := Encode(d)
-		// decode
-		de := Decode(e)
-
-		// nil endpoint returns nil
-		if d == nil {
-			if e != nil {
-				t.Fatalf("expected nil got %v", e)
-			}
-			if de != nil {
-				t.Fatalf("expected nil got %v", de)
-			}
-
-			continue
-		}
-
-		// check encoded map
-		name := e["endpoint"]
-		desc := e["description"]
-		method := strings.Split(e["method"], ",")
-		path := strings.Split(e["path"], ",")
-		host := strings.Split(e["host"], ",")
-		handler := e["handler"]
-
-		if name != d.Name {
-			t.Fatalf("expected %v got %v", d.Name, name)
-		}
-		if desc != d.Description {
-			t.Fatalf("expected %v got %v", d.Description, desc)
-		}
-		if handler != d.Handler {
-			t.Fatalf("expected %v got %v", d.Handler, handler)
-		}
-		if ok := compare(d.Method, method); !ok {
-			t.Fatalf("expected %v got %v", d.Method, method)
-		}
-		if ok := compare(d.Path, path); !ok {
-			t.Fatalf("expected %v got %v", d.Path, path)
-		}
-		if ok := compare(d.Host, host); !ok {
-			t.Fatalf("expected %v got %v", d.Host, host)
-		}
-
-		if de.Name != d.Name {
-			t.Fatalf("expected %v got %v", d.Name, de.Name)
-		}
-		if de.Description != d.Description {
-			t.Fatalf("expected %v got %v", d.Description, de.Description)
-		}
-		if de.Handler != d.Handler {
-			t.Fatalf("expected %v got %v", d.Handler, de.Handler)
-		}
-		if ok := compare(d.Method, de.Method); !ok {
-			t.Fatalf("expected %v got %v", d.Method, de.Method)
-		}
-		if ok := compare(d.Path, de.Path); !ok {
-			t.Fatalf("expected %v got %v", d.Path, de.Path)
-		}
-		if ok := compare(d.Host, de.Host); !ok {
-			t.Fatalf("expected %v got %v", d.Host, de.Host)
-		}
-	}
-}
-
-func TestValidate(t *testing.T) {
-	epPcre := &Endpoint{
-		Name:        "Foo.Bar",
-		Description: "A test endpoint",
-		Handler:     "meta",
-		Host:        []string{"foo.com"},
-		Method:      []string{"GET"},
-		Path:        []string{"^/test/?$"},
-	}
-	if err := Validate(epPcre); err != nil {
-		t.Fatal(err)
-	}
-
-	epGpath := &Endpoint{
-		Name:        "Foo.Bar",
-		Description: "A test endpoint",
-		Handler:     "meta",
-		Host:        []string{"foo.com"},
-		Method:      []string{"GET"},
-		Path:        []string{"/test/{id}"},
-	}
-	if err := Validate(epGpath); err != nil {
-		t.Fatal(err)
-	}
-
-	epPcreInvalid := &Endpoint{
-		Name:        "Foo.Bar",
-		Description: "A test endpoint",
-		Handler:     "meta",
-		Host:        []string{"foo.com"},
-		Method:      []string{"GET"},
-		Path:        []string{"/test/?$"},
-	}
-	if err := Validate(epPcreInvalid); err == nil {
-		t.Fatalf("invalid pcre %v", epPcreInvalid.Path[0])
-	}
-}

api/handler/handler.go

@@ -1,14 +0,0 @@
-// Package handler provides http handlers
-package handler
-
-import (
-	"net/http"
-)
-
-// Handler represents a HTTP handler that manages a request
-type Handler interface {
-	// standard http handler
-	http.Handler
-	// name of handler
-	String() string
-}

api/handler/options.go

@@ -1,70 +0,0 @@
-package handler
-
-import (
-	"github.com/unistack-org/micro/v3/api/router"
-	"github.com/unistack-org/micro/v3/client"
-	"github.com/unistack-org/micro/v3/logger"
-)
-
-// DefaultMaxRecvSize specifies max recv size for handler
-var DefaultMaxRecvSize int64 = 1024 * 1024 * 100 // 10Mb
-
-// Options struct holds handler options
-type Options struct {
-	Router      router.Router
-	Client      client.Client
-	Logger      logger.Logger
-	Namespace   string
-	MaxRecvSize int64
-}
-
-// Option func signature
-type Option func(o *Options)
-
-// NewOptions creates new options struct and fills it
-func NewOptions(opts ...Option) Options {
-	options := Options{
-		Client:      client.DefaultClient,
-		Router:      router.DefaultRouter,
-		Logger:      logger.DefaultLogger,
-		MaxRecvSize: DefaultMaxRecvSize,
-	}
-	for _, o := range opts {
-		o(&options)
-	}
-
-	// set namespace if blank
-	if len(options.Namespace) == 0 {
-		WithNamespace("go.micro.api")(&options)
-	}
-
-	return options
-}
-
-// WithNamespace specifies the namespace for the handler
-func WithNamespace(s string) Option {
-	return func(o *Options) {
-		o.Namespace = s
-	}
-}
-
-// WithRouter specifies a router to be used by the handler
-func WithRouter(r router.Router) Option {
-	return func(o *Options) {
-		o.Router = r
-	}
-}
-
-// WithClient specifies client to be used by the handler
-func WithClient(c client.Client) Option {
-	return func(o *Options) {
-		o.Client = c
-	}
-}
-
-// WithMaxRecvSize specifies max body size
-func WithMaxRecvSize(size int64) Option {
-	return func(o *Options) {
-		o.MaxRecvSize = size
-	}
-}

api/resolver/grpc/grpc.go

@@ -1,47 +0,0 @@
-// Package grpc resolves a grpc service like /greeter.Say/Hello to greeter service
-package grpc
-
-import (
-	"errors"
-	"net/http"
-	"strings"
-
-	"github.com/unistack-org/micro/v3/api/resolver"
-)
-
-// Resolver struct
-type Resolver struct {
-	opts resolver.Options
-}
-
-// Resolve func to resolve enndpoint
-func (r *Resolver) Resolve(req *http.Request, opts ...resolver.ResolveOption) (*resolver.Endpoint, error) {
-	// parse options
-	options := resolver.NewResolveOptions(opts...)
-
-	// /foo.Bar/Service
-	if req.URL.Path == "/" {
-		return nil, errors.New("unknown name")
-	}
-	// [foo.Bar, Service]
-	parts := strings.Split(req.URL.Path[1:], "/")
-	// [foo, Bar]
-	name := strings.Split(parts[0], ".")
-	// foo
-	return &resolver.Endpoint{
-		Name:   strings.Join(name[:len(name)-1], "."),
-		Host:   req.Host,
-		Method: req.Method,
-		Path:   req.URL.Path,
-		Domain: options.Domain,
-	}, nil
-}
-
-func (r *Resolver) String() string {
-	return "grpc"
-}
-
-// NewResolver is used to create new Resolver
-func NewResolver(opts ...resolver.Option) resolver.Resolver {
-	return &Resolver{opts: resolver.NewOptions(opts...)}
-}

api/resolver/host/host.go

@@ -1,35 +0,0 @@
-// Package host resolves using http host
-package host
-
-import (
-	"net/http"
-
-	"github.com/unistack-org/micro/v3/api/resolver"
-)
-
-type hostResolver struct {
-	opts resolver.Options
-}
-
-// Resolve endpoint
-func (r *hostResolver) Resolve(req *http.Request, opts ...resolver.ResolveOption) (*resolver.Endpoint, error) {
-	// parse options
-	options := resolver.NewResolveOptions(opts...)
-
-	return &resolver.Endpoint{
-		Name:   req.Host,
-		Host:   req.Host,
-		Method: req.Method,
-		Path:   req.URL.Path,
-		Domain: options.Domain,
-	}, nil
-}
-
-func (r *hostResolver) String() string {
-	return "host"
-}
-
-// NewResolver creates new host api resolver
-func NewResolver(opts ...resolver.Option) resolver.Resolver {
-	return &hostResolver{opts: resolver.NewOptions(opts...)}
-}

api/resolver/options.go

@@ -1,70 +0,0 @@
-package resolver
-
-import (
-	"context"
-
-	"github.com/unistack-org/micro/v3/register"
-)
-
-// Options struct
-type Options struct {
-	// Context is for external defined options
-	Context context.Context
-	// Handler name
-	Handler string
-	// ServicePrefix is the prefix
-	ServicePrefix string
-}
-
-// Option func
-type Option func(o *Options)
-
-// WithHandler sets the handler being used
-func WithHandler(h string) Option {
-	return func(o *Options) {
-		o.Handler = h
-	}
-}
-
-// WithServicePrefix sets the ServicePrefix option
-func WithServicePrefix(p string) Option {
-	return func(o *Options) {
-		o.ServicePrefix = p
-	}
-}
-
-// NewOptions returns new initialised options
-func NewOptions(opts ...Option) Options {
-	options := Options{
-		Context: context.Background(),
-	}
-	for _, o := range opts {
-		o(&options)
-	}
-	return options
-}
-
-// ResolveOptions are used when resolving a request
-type ResolveOptions struct {
-	Domain string
-}
-
-// ResolveOption sets an option
-type ResolveOption func(*ResolveOptions)
-
-// Domain sets the resolve Domain option
-func Domain(n string) ResolveOption {
-	return func(o *ResolveOptions) {
-		o.Domain = n
-	}
-}
-
-// NewResolveOptions returns new initialised resolve options
-func NewResolveOptions(opts ...ResolveOption) ResolveOptions {
-	options := ResolveOptions{Domain: register.DefaultDomain}
-	for _, o := range opts {
-		o(&options)
-	}
-
-	return options
-}

api/resolver/path/path.go

@@ -1,44 +0,0 @@
-// Package path resolves using http path
-package path
-
-import (
-	"net/http"
-	"strings"
-
-	"github.com/unistack-org/micro/v3/api/resolver"
-)
-
-// Resolver the path resolver
-type Resolver struct {
-	opts resolver.Options
-}
-
-// Resolve resolves endpoint
-func (r *Resolver) Resolve(req *http.Request, opts ...resolver.ResolveOption) (*resolver.Endpoint, error) {
-	// parse options
-	options := resolver.NewResolveOptions(opts...)
-
-	if req.URL.Path == "/" {
-		return nil, resolver.ErrNotFound
-	}
-
-	parts := strings.Split(req.URL.Path[1:], "/")
-
-	return &resolver.Endpoint{
-		Name:   r.opts.ServicePrefix + "." + parts[0],
-		Host:   req.Host,
-		Method: req.Method,
-		Path:   req.URL.Path,
-		Domain: options.Domain,
-	}, nil
-}
-
-// String retruns the string representation
-func (r *Resolver) String() string {
-	return "path"
-}
-
-// NewResolver returns new path resolver
-func NewResolver(opts ...resolver.Option) resolver.Resolver {
-	return &Resolver{opts: resolver.NewOptions(opts...)}
-}

api/resolver/resolver.go

@@ -1,34 +0,0 @@
-// Package resolver resolves a http request to an endpoint
-package resolver
-
-import (
-	"errors"
-	"net/http"
-)
-
-var (
-	// ErrNotFound returned when endpoint is not found
-	ErrNotFound = errors.New("not found")
-	// ErrInvalidPath returned on invalid path
-	ErrInvalidPath = errors.New("invalid path")
-)
-
-// Resolver resolves requests to endpoints
-type Resolver interface {
-	Resolve(r *http.Request, opts ...ResolveOption) (*Endpoint, error)
-	String() string
-}
-
-// Endpoint is the endpoint for a http request
-type Endpoint struct {
-	// Endpoint name e.g greeter
-	Name string
-	// HTTP Host e.g example.com
-	Host string
-	// HTTP Methods e.g GET, POST
-	Method string
-	// HTTP Path e.g /greeter.
-	Path string
-	// Domain endpoint exists within
-	Domain string
-}

api/resolver/subdomain/subdomain.go

@@ -1,90 +0,0 @@
-// Package subdomain is a resolver which uses the subdomain to determine the domain to route to. It
-// offloads the endpoint resolution to a child resolver which is provided in New.
-package subdomain
-
-import (
-	"net"
-	"net/http"
-	"strings"
-
-	"github.com/unistack-org/micro/v3/api/resolver"
-	"github.com/unistack-org/micro/v3/logger"
-	"golang.org/x/net/publicsuffix"
-)
-
-// NewResolver creates new subdomain api resolver
-func NewResolver(parent resolver.Resolver, opts ...resolver.Option) resolver.Resolver {
-	options := resolver.NewOptions(opts...)
-	return &subdomainResolver{opts: options, Resolver: parent}
-}
-
-type subdomainResolver struct {
-	resolver.Resolver
-	opts resolver.Options
-}
-
-// Resolve resolve endpoint based on subdomain
-func (r *subdomainResolver) Resolve(req *http.Request, opts ...resolver.ResolveOption) (*resolver.Endpoint, error) {
-	if dom := r.Domain(req); len(dom) > 0 {
-		opts = append(opts, resolver.Domain(dom))
-	}
-
-	return r.Resolver.Resolve(req, opts...)
-}
-
-// Domain returns domain
-func (r *subdomainResolver) Domain(req *http.Request) string {
-	// determine the host, e.g. foobar.m3o.app
-	host := req.URL.Hostname()
-	if len(host) == 0 {
-		if h, _, err := net.SplitHostPort(req.Host); err == nil {
-			host = h // host does contain a port
-		} else if strings.Contains(err.Error(), "missing port in address") {
-			host = req.Host // host does not contain a port
-		}
-	}
-
-	// check for an ip address
-	if net.ParseIP(host) != nil {
-		return ""
-	}
-
-	// check for dev environment
-	if host == "localhost" || host == "127.0.0.1" {
-		return ""
-	}
-
-	// extract the top level domain plus one (e.g. 'myapp.com')
-	domain, err := publicsuffix.EffectiveTLDPlusOne(host)
-	if err != nil {
-		if logger.V(logger.DebugLevel) {
-			logger.Debug(r.opts.Context, "Unable to extract domain from %v", host)
-		}
-		return ""
-	}
-
-	// there was no subdomain
-	if host == domain {
-		return ""
-	}
-
-	// remove the domain from the host, leaving the subdomain, e.g. "staging.foo.myapp.com" => "staging.foo"
-	subdomain := strings.TrimSuffix(host, "."+domain)
-
-	// ignore the API subdomain
-	if subdomain == "api" {
-		return ""
-	}
-
-	// return the reversed subdomain as the namespace, e.g. "staging.foo" => "foo-staging"
-	comps := strings.Split(subdomain, ".")
-	for i := len(comps)/2 - 1; i >= 0; i-- {
-		opp := len(comps) - 1 - i
-		comps[i], comps[opp] = comps[opp], comps[i]
-	}
-	return strings.Join(comps, "-")
-}
-
-func (r *subdomainResolver) String() string {
-	return "subdomain"
-}

api/resolver/subdomain/subdomain_test.go

@@ -1,73 +0,0 @@
-package subdomain
-
-import (
-	"net/http"
-	"net/url"
-	"testing"
-
-	"github.com/unistack-org/micro/v3/api/resolver/vpath"
-)
-
-func TestResolve(t *testing.T) {
-	tt := []struct {
-		Name   string
-		Host   string
-		Result string
-	}{
-		{
-			Name:   "Top level domain",
-			Host:   "micro.mu",
-			Result: "micro",
-		},
-		{
-			Name:   "Effective top level domain",
-			Host:   "micro.com.au",
-			Result: "micro",
-		},
-		{
-			Name:   "Subdomain dev",
-			Host:   "dev.micro.mu",
-			Result: "dev",
-		},
-		{
-			Name:   "Subdomain foo",
-			Host:   "foo.micro.mu",
-			Result: "foo",
-		},
-		{
-			Name:   "Multi-level subdomain",
-			Host:   "staging.myapp.m3o.app",
-			Result: "myapp-staging",
-		},
-		{
-			Name:   "Dev host",
-			Host:   "127.0.0.1",
-			Result: "micro",
-		},
-		{
-			Name:   "Localhost",
-			Host:   "localhost",
-			Result: "micro",
-		},
-		{
-			Name:   "IP host",
-			Host:   "81.151.101.146",
-			Result: "micro",
-		},
-	}
-
-	for _, tc := range tt {
-		t.Run(tc.Name, func(t *testing.T) {
-			r := NewResolver(vpath.NewResolver())
-			result, err := r.Resolve(&http.Request{URL: &url.URL{Host: tc.Host, Path: "foo/bar"}})
-			if err != nil {
-				t.Fatal(err)
-			}
-			if result != nil {
-				if tc.Result != result.Domain {
-					t.Fatalf("Expected %v but got %v", tc.Result, result.Domain)
-				}
-			}
-		})
-	}
-}

api/resolver/vpath/vpath.go

@@ -1,75 +0,0 @@
-// Package vpath resolves using http path and recognised versioned urls
-package vpath
-
-import (
-	"errors"
-	"net/http"
-	"regexp"
-	"strings"
-
-	"github.com/unistack-org/micro/v3/api/resolver"
-)
-
-// NewResolver creates new vpath api resolver
-func NewResolver(opts ...resolver.Option) resolver.Resolver {
-	return &vpathResolver{opts: resolver.NewOptions(opts...)}
-}
-
-type vpathResolver struct {
-	opts resolver.Options
-}
-
-var re = regexp.MustCompile("^v[0-9]+$")
-
-// Resolve endpoint
-func (r *vpathResolver) Resolve(req *http.Request, opts ...resolver.ResolveOption) (*resolver.Endpoint, error) {
-	if req.URL.Path == "/" {
-		return nil, errors.New("unknown name")
-	}
-
-	options := resolver.NewResolveOptions(opts...)
-
-	parts := strings.Split(req.URL.Path[1:], "/")
-	if len(parts) == 1 {
-		return &resolver.Endpoint{
-			Name:   r.withPrefix(parts...),
-			Host:   req.Host,
-			Method: req.Method,
-			Path:   req.URL.Path,
-			Domain: options.Domain,
-		}, nil
-	}
-
-	// /v1/foo
-	if re.MatchString(parts[0]) {
-		return &resolver.Endpoint{
-			Name:   r.withPrefix(parts[0:2]...),
-			Host:   req.Host,
-			Method: req.Method,
-			Path:   req.URL.Path,
-			Domain: options.Domain,
-		}, nil
-	}
-
-	return &resolver.Endpoint{
-		Name:   r.withPrefix(parts[0]),
-		Host:   req.Host,
-		Method: req.Method,
-		Path:   req.URL.Path,
-		Domain: options.Domain,
-	}, nil
-}
-
-func (r *vpathResolver) String() string {
-	return "vpath"
-}
-
-// withPrefix transforms "foo" into "go.micro.api.foo"
-func (r *vpathResolver) withPrefix(parts ...string) string {
-	p := r.opts.ServicePrefix
-	if len(p) > 0 {
-		parts = append([]string{p}, parts...)
-	}
-
-	return strings.Join(parts, ".")
-}

api/router/options.go

@@ -1,75 +0,0 @@
-package router
-
-import (
-	"context"
-
-	"github.com/unistack-org/micro/v3/api/resolver"
-	"github.com/unistack-org/micro/v3/api/resolver/vpath"
-	"github.com/unistack-org/micro/v3/logger"
-	"github.com/unistack-org/micro/v3/register"
-)
-
-// Options holds the options for api router
-type Options struct {
-	// Register for service lookup
-	Register register.Register
-	// Resolver to use
-	Resolver resolver.Resolver
-	// Logger micro logger
-	Logger logger.Logger
-	// Context is for external options
-	Context context.Context
-	// Handler name
-	Handler string
-}
-
-// Option func signature
-type Option func(o *Options)
-
-// NewOptions returns options struct filled by opts
-func NewOptions(opts ...Option) Options {
-	options := Options{
-		Context: context.Background(),
-		Handler: "meta",
-	}
-
-	for _, o := range opts {
-		o(&options)
-	}
-
-	if options.Resolver == nil {
-		options.Resolver = vpath.NewResolver(
-			resolver.WithHandler(options.Handler),
-		)
-	}
-
-	return options
-}
-
-// WithContext sets the context
-func WithContext(ctx context.Context) Option {
-	return func(o *Options) {
-		o.Context = ctx
-	}
-}
-
-// WithHandler sets the handler
-func WithHandler(h string) Option {
-	return func(o *Options) {
-		o.Handler = h
-	}
-}
-
-// WithRegister sets the register
-func WithRegister(r register.Register) Option {
-	return func(o *Options) {
-		o.Register = r
-	}
-}
-
-// WithResolver sets the resolver
-func WithResolver(r resolver.Resolver) Option {
-	return func(o *Options) {
-		o.Resolver = r
-	}
-}

api/router/router.go

@@ -1,31 +0,0 @@
-// Package router provides api service routing
-package router
-
-import (
-	"net/http"
-
-	"github.com/unistack-org/micro/v3/api"
-)
-
-// DefaultRouter contains default router implementation
-var DefaultRouter Router
-
-// Router is used to determine an endpoint for a request
-type Router interface {
-	// Returns options
-	Options() Options
-	// Init initialize router
-	Init(...Option) error
-	// Stop the router
-	Close() error
-	// Endpoint returns an api.Service endpoint or an error if it does not exist
-	Endpoint(r *http.Request) (*api.Service, error)
-	// Register endpoint in router
-	Register(ep *api.Endpoint) error
-	// Deregister endpoint from router
-	Deregister(ep *api.Endpoint) error
-	// Route returns an api.Service route
-	Route(r *http.Request) (*api.Service, error)
-	// String representation of router
-	String() string
-}

auth/auth.go

@@ -1,141 +0,0 @@
-// Package auth provides authentication and authorization capability
-package auth
-
-import (
-	"context"
-	"errors"
-	"time"
-
-	"github.com/unistack-org/micro/v3/metadata"
-)
-
-const (
-	// BearerScheme used for Authorization header
-	BearerScheme = "Bearer "
-	// ScopePublic is the scope applied to a rule to allow access to the public
-	ScopePublic = ""
-	// ScopeAccount is the scope applied to a rule to limit to users with any valid account
-	ScopeAccount = "*"
-)
-
-var (
-	// DefaultAuth holds default auth implementation
-	DefaultAuth Auth = NewAuth()
-	// ErrInvalidToken is when the token provided is not valid
-	ErrInvalidToken = errors.New("invalid token provided")
-	// ErrForbidden is when a user does not have the necessary scope to access a resource
-	ErrForbidden = errors.New("resource forbidden")
-)
-
-// Auth provides authentication and authorization
-type Auth interface {
-	// Init the auth
-	Init(opts ...Option) error
-	// Options set for auth
-	Options() Options
-	// Generate a new account
-	Generate(id string, opts ...GenerateOption) (*Account, error)
-	// Verify an account has access to a resource using the rules
-	Verify(acc *Account, res *Resource, opts ...VerifyOption) error
-	// Inspect a token
-	Inspect(token string) (*Account, error)
-	// Token generated using refresh token or credentials
-	Token(opts ...TokenOption) (*Token, error)
-	// Grant access to a resource
-	Grant(rule *Rule) error
-	// Revoke access to a resource
-	Revoke(rule *Rule) error
-	// Rules returns all the rules used to verify requests
-	Rules(...RulesOption) ([]*Rule, error)
-	// String returns the name of the implementation
-	String() string
-}
-
-// Account provided by an auth provider
-type Account struct {
-	// Metadata any other associated metadata
-	Metadata metadata.Metadata `json:"metadata"`
-	// ID of the account e.g. email or uuid
-	ID string `json:"id"`
-	// Type of the account, e.g. service
-	Type string `json:"type"`
-	// Issuer of the account
-	Issuer string `json:"issuer"`
-	// Secret for the account, e.g. the password
-	Secret string `json:"secret"`
-	// Scopes the account has access to
-	Scopes []string `json:"scopes"`
-}
-
-// Token can be short or long lived
-type Token struct {
-	// Time of token creation
-	Created time.Time `json:"created"`
-	// Time of token expiry
-	Expiry time.Time `json:"expiry"`
-	// The token to be used for accessing resources
-	AccessToken string `json:"access_token"`
-	// RefreshToken to be used to generate a new token
-	RefreshToken string `json:"refresh_token"`
-}
-
-// Expired returns a boolean indicating if the token needs to be refreshed
-func (t *Token) Expired() bool {
-	return t.Expiry.Unix() < time.Now().Unix()
-}
-
-// Resource is an entity such as a user or
-type Resource struct {
-	// Name of the resource, e.g. go.micro.service.notes
-	Name string `json:"name"`
-	// Type of resource, e.g. service
-	Type string `json:"type"`
-	// Endpoint resource e.g NotesService.Create
-	Endpoint string `json:"endpoint"`
-}
-
-// Access defines the type of access a rule grants
-type Access int
-
-const (
-	// AccessGranted to a resource
-	AccessGranted Access = iota
-	// AccessDenied to a resource
-	AccessDenied
-)
-
-// Rule is used to verify access to a resource
-type Rule struct {
-	// Resource that rule belongs to
-	Resource *Resource
-	// ID of the rule
-	ID string
-	// Scope of the rule
-	Scope string
-	// Access flag allow/deny
-	Access Access
-	// Priority holds the rule priority
-	Priority int32
-}
-
-type accountKey struct{}
-
-// AccountFromContext gets the account from the context, which
-// is set by the auth wrapper at the start of a call. If the account
-// is not set, a nil account will be returned. The error is only returned
-// when there was a problem retrieving an account
-func AccountFromContext(ctx context.Context) (*Account, bool) {
-	if ctx == nil {
-		return nil, false
-	}
-	acc, ok := ctx.Value(accountKey{}).(*Account)
-	return acc, ok
-}
-
-// ContextWithAccount sets the account in the context
-func ContextWithAccount(ctx context.Context, account *Account) context.Context {
-	if ctx == nil {
-		ctx = context.Background()
-	}
-	return context.WithValue(ctx, accountKey{}, account)
-}

auth/noop.go

@@ -1,79 +0,0 @@
-package auth
-
-import (
-	"github.com/google/uuid"
-)
-
-type noopAuth struct {
-	opts Options
-}
-
-// String returns the name of the implementation
-func (n *noopAuth) String() string {
-	return "noop"
-}
-
-// Init the auth
-func (n *noopAuth) Init(opts ...Option) error {
-	for _, o := range opts {
-		o(&n.opts)
-	}
-	return nil
-}
-
-// Options set for auth
-func (n *noopAuth) Options() Options {
-	return n.opts
-}
-
-// Generate a new account
-func (n *noopAuth) Generate(id string, opts ...GenerateOption) (*Account, error) {
-	options := NewGenerateOptions(opts...)
-
-	return &Account{
-		ID:       id,
-		Secret:   options.Secret,
-		Metadata: options.Metadata,
-		Scopes:   options.Scopes,
-		Issuer:   n.Options().Issuer,
-	}, nil
-}
-
-// Grant access to a resource
-func (n *noopAuth) Grant(rule *Rule) error {
-	return nil
-}
-
-// Revoke access to a resource
-func (n *noopAuth) Revoke(rule *Rule) error {
-	return nil
-}
-
-// Rules used to verify requests
-func (n *noopAuth) Rules(opts ...RulesOption) ([]*Rule, error) {
-	return []*Rule{}, nil
-}
-
-// Verify an account has access to a resource
-func (n *noopAuth) Verify(acc *Account, res *Resource, opts ...VerifyOption) error {
-	return nil
-}
-
-// Inspect a token
-func (n *noopAuth) Inspect(token string) (*Account, error) {
-	uid, err := uuid.NewRandom()
-	if err != nil {
-		return nil, err
-	}
-	return &Account{ID: uid.String(), Issuer: n.Options().Issuer}, nil
-}
-
-// Token generation using an account id and secret
-func (n *noopAuth) Token(opts ...TokenOption) (*Token, error) {
-	return &Token{}, nil
-}
-
-// NewAuth returns new noop auth
-func NewAuth(opts ...Option) Auth {
-	return &noopAuth{opts: NewOptions(opts...)}
-}

auth/options.go

@@ -1,311 +0,0 @@
-package auth
-
-import (
-	"context"
-	"time"
-
-	"github.com/unistack-org/micro/v3/logger"
-	"github.com/unistack-org/micro/v3/metadata"
-	"github.com/unistack-org/micro/v3/meter"
-	"github.com/unistack-org/micro/v3/store"
-	"github.com/unistack-org/micro/v3/tracer"
-)
-
-// NewOptions creates Options struct from slice of options
-func NewOptions(opts ...Option) Options {
-	options := Options{
-		Tracer: tracer.DefaultTracer,
-		Logger: logger.DefaultLogger,
-		Meter:  meter.DefaultMeter,
-	}
-	for _, o := range opts {
-		o(&options)
-	}
-	return options
-}
-
-// Options struct holds auth options
-type Options struct {
-	// Context holds the external options
-	Context context.Context
-	// Meter used for metrics
-	Meter meter.Meter
-	// Logger used for logging
-	Logger logger.Logger
-	// Tracer used for tracing
-	Tracer tracer.Tracer
-	// Store used for stre data
-	Store store.Store
-	// Token is the services token used to authenticate itself
-	Token *Token
-	// LoginURL is the relative url path where a user can login
-	LoginURL string
-	// PrivateKey for encoding JWTs
-	PrivateKey string
-	// PublicKey for decoding JWTs
-	PublicKey string
-	// Secret is used to authenticate the service
-	Secret string
-	// ID is the services auth ID
-	ID string
-	// Issuer of the service's account
-	Issuer string
-	// Name holds the auth name
-	Name string
-	// Addrs sets the addresses of auth
-	Addrs []string
-}
-
-// Option func
-type Option func(o *Options)
-
-// Addrs is the auth addresses to use
-func Addrs(addrs ...string) Option {
-	return func(o *Options) {
-		o.Addrs = addrs
-	}
-}
-
-// Name sets the name
-func Name(n string) Option {
-	return func(o *Options) {
-		o.Name = n
-	}
-}
-
-// Issuer of the services account
-func Issuer(i string) Option {
-	return func(o *Options) {
-		o.Issuer = i
-	}
-}
-
-// Store to back auth
-func Store(s store.Store) Option {
-	return func(o *Options) {
-		o.Store = s
-	}
-}
-
-// PublicKey is the JWT public key
-func PublicKey(key string) Option {
-	return func(o *Options) {
-		o.PublicKey = key
-	}
-}
-
-// PrivateKey is the JWT private key
-func PrivateKey(key string) Option {
-	return func(o *Options) {
-		o.PrivateKey = key
-	}
-}
-
-// Credentials sets the auth credentials
-func Credentials(id, secret string) Option {
-	return func(o *Options) {
-		o.ID = id
-		o.Secret = secret
-	}
-}
-
-// ClientToken sets the auth token to use when making requests
-func ClientToken(token *Token) Option {
-	return func(o *Options) {
-		o.Token = token
-	}
-}
-
-// LoginURL sets the auth LoginURL
-func LoginURL(url string) Option {
-	return func(o *Options) {
-		o.LoginURL = url
-	}
-}
-
-// GenerateOptions struct
-type GenerateOptions struct {
-	Metadata metadata.Metadata
-	Provider string
-	Type     string
-	Secret   string
-	Issuer   string
-	Scopes   []string
-}
-
-// GenerateOption func
-type GenerateOption func(o *GenerateOptions)
-
-// WithSecret for the generated account
-func WithSecret(s string) GenerateOption {
-	return func(o *GenerateOptions) {
-		o.Secret = s
-	}
-}
-
-// WithType for the generated account
-func WithType(t string) GenerateOption {
-	return func(o *GenerateOptions) {
-		o.Type = t
-	}
-}
-
-// WithMetadata for the generated account
-func WithMetadata(md metadata.Metadata) GenerateOption {
-	return func(o *GenerateOptions) {
-		o.Metadata = metadata.Copy(md)
-	}
-}
-
-// WithProvider for the generated account
-func WithProvider(p string) GenerateOption {
-	return func(o *GenerateOptions) {
-		o.Provider = p
-	}
-}
-
-// WithScopes for the generated account
-func WithScopes(s ...string) GenerateOption {
-	return func(o *GenerateOptions) {
-		o.Scopes = s
-	}
-}
-
-// WithIssuer for the generated account
-func WithIssuer(i string) GenerateOption {
-	return func(o *GenerateOptions) {
-		o.Issuer = i
-	}
-}
-
-// NewGenerateOptions from a slice of options
-func NewGenerateOptions(opts ...GenerateOption) GenerateOptions {
-	var options GenerateOptions
-	for _, o := range opts {
-		o(&options)
-	}
-	return options
-}
-
-// TokenOptions struct
-type TokenOptions struct {
-	ID           string
-	Secret       string
-	RefreshToken string
-	Issuer       string
-	Expiry       time.Duration
-}
-
-// TokenOption func
-type TokenOption func(o *TokenOptions)
-
-// WithExpiry for the token
-func WithExpiry(ex time.Duration) TokenOption {
-	return func(o *TokenOptions) {
-		o.Expiry = ex
-	}
-}
-
-// WithCredentials sets tye id and secret
-func WithCredentials(id, secret string) TokenOption {
-	return func(o *TokenOptions) {
-		o.ID = id
-		o.Secret = secret
-	}
-}
-
-// WithToken sets the refresh token
-func WithToken(rt string) TokenOption {
-	return func(o *TokenOptions) {
-		o.RefreshToken = rt
-	}
-}
-
-// WithTokenIssuer sets the token issuer option
-func WithTokenIssuer(iss string) TokenOption {
-	return func(o *TokenOptions) {
-		o.Issuer = iss
-	}
-}
-
-// NewTokenOptions from a slice of options
-func NewTokenOptions(opts ...TokenOption) TokenOptions {
-	var options TokenOptions
-	for _, o := range opts {
-		o(&options)
-	}
-
-	// set default expiry of token
-	if options.Expiry == 0 {
-		options.Expiry = time.Minute
-	}
-
-	return options
-}
-
-// VerifyOptions struct
-type VerifyOptions struct {
-	Context   context.Context
-	Namespace string
-}
-
-// VerifyOption func
-type VerifyOption func(o *VerifyOptions)
-
-// VerifyContext pass context to verify
-func VerifyContext(ctx context.Context) VerifyOption {
-	return func(o *VerifyOptions) {
-		o.Context = ctx
-	}
-}
-
-// VerifyNamespace sets thhe namespace for verify
-func VerifyNamespace(ns string) VerifyOption {
-	return func(o *VerifyOptions) {
-		o.Namespace = ns
-	}
-}
-
-// RulesOptions struct
-type RulesOptions struct {
-	Context   context.Context
-	Namespace string
-}
-
-// RulesOption func
-type RulesOption func(o *RulesOptions)
-
-// RulesContext pass rules context
-func RulesContext(ctx context.Context) RulesOption {
-	return func(o *RulesOptions) {
-		o.Context = ctx
-	}
-}
-
-// RulesNamespace sets the rule namespace
-func RulesNamespace(ns string) RulesOption {
-	return func(o *RulesOptions) {
-		o.Namespace = ns
-	}
-}
-
-// Logger sets the logger
-func Logger(l logger.Logger) Option {
-	return func(o *Options) {
-		o.Logger = l
-	}
-}
-
-// Meter sets the meter
-func Meter(m meter.Meter) Option {
-	return func(o *Options) {
-		o.Meter = m
-	}
-}
-
-// Tracer sets the meter
-func Tracer(t tracer.Tracer) Option {
-	return func(o *Options) {
-		o.Tracer = t
-	}
-}

auth/rules.go

@@ -1,92 +0,0 @@
-package auth
-
-import (
-	"fmt"
-	"sort"
-	"strings"
-)
-
-// VerifyAccess an account has access to a resource using the rules provided. If the account does not have
-// access an error will be returned. If there are no rules provided which match the resource, an error
-// will be returned
-//nolint:gocyclo
-func VerifyAccess(rules []*Rule, acc *Account, res *Resource) error {
-	// the rule is only to be applied if the type matches the resource or is catch-all (*)
-	validTypes := []string{"*", res.Type}
-
-	// the rule is only to be applied if the name matches the resource or is catch-all (*)
-	validNames := []string{"*", res.Name}
-
-	// rules can have wildcard excludes on endpoints since this can also be a path for web services,
-	// e.g. /foo/* would include /foo/bar. We also want to check for wildcards and the exact endpoint
-	validEndpoints := []string{"*", res.Endpoint}
-	if comps := strings.Split(res.Endpoint, "/"); len(comps) > 1 {
-		for i := 1; i < len(comps)+1; i++ {
-			wildcard := fmt.Sprintf("%v/*", strings.Join(comps[0:i], "/"))
-			validEndpoints = append(validEndpoints, wildcard)
-		}
-	}
-
-	// filter the rules to the ones which match the criteria above
-	filteredRules := make([]*Rule, 0)
-	for _, rule := range rules {
-		if !include(validTypes, rule.Resource.Type) {
-			continue
-		}
-		if !include(validNames, rule.Resource.Name) {
-			continue
-		}
-		if !include(validEndpoints, rule.Resource.Endpoint) {
-			continue
-		}
-		filteredRules = append(filteredRules, rule)
-	}
-
-	// sort the filtered rules by priority, highest to lowest
-	sort.SliceStable(filteredRules, func(i, j int) bool {
-		return filteredRules[i].Priority > filteredRules[j].Priority
-	})
-
-	// loop through the rules and check for a rule which applies to this account
-	for _, rule := range filteredRules {
-		// a blank scope indicates the rule applies to everyone, even nil accounts
-		if rule.Scope == ScopePublic && rule.Access == AccessDenied {
-			return ErrForbidden
-		} else if rule.Scope == ScopePublic && rule.Access == AccessGranted {
-			return nil
-		}
-
-		// all further checks require an account
-		if acc == nil {
-			continue
-		}
-
-		// this rule applies to any account
-		if rule.Scope == ScopeAccount && rule.Access == AccessDenied {
-			return ErrForbidden
-		} else if rule.Scope == ScopeAccount && rule.Access == AccessGranted {
-			return nil
-		}
-
-		// if the account has the necessary scope
-		if include(acc.Scopes, rule.Scope) && rule.Access == AccessDenied {
-			return ErrForbidden
-		} else if include(acc.Scopes, rule.Scope) && rule.Access == AccessGranted {
-			return nil
-		}
-	}
-
-	// if no rules matched then return forbidden
-	return ErrForbidden
-}
-
-// include is a helper function which checks to see if the slice contains the value. includes is
-// not case sensitive.
-func include(slice []string, val string) bool {
-	for _, s := range slice {
-		if strings.EqualFold(s, val) {
-			return true
-		}
-	}
-	return false
-}

auth/rules_test.go

@@ -1,288 +0,0 @@
-package auth
-
-import (
-	"testing"
-)
-
-func TestVerify(t *testing.T) {
-	srvResource := &Resource{
-		Type:     "service",
-		Name:     "go.micro.service.foo",
-		Endpoint: "Foo.Bar",
-	}
-
-	webResource := &Resource{
-		Type:     "service",
-		Name:     "go.micro.web.foo",
-		Endpoint: "/foo/bar",
-	}
-
-	catchallResource := &Resource{
-		Type:     "*",
-		Name:     "*",
-		Endpoint: "*",
-	}
-
-	tt := []struct {
-		Error    error
-		Account  *Account
-		Resource *Resource
-		Name     string
-		Rules    []*Rule
-	}{
-		{
-			Name:     "NoRules",
-			Rules:    []*Rule{},
-			Account:  nil,
-			Resource: srvResource,
-			Error:    ErrForbidden,
-		},
-		{
-			Name:     "CatchallPublicAccount",
-			Account:  &Account{},
-			Resource: srvResource,
-			Rules: []*Rule{
-				{
-					Scope:    "",
-					Resource: catchallResource,
-				},
-			},
-		},
-		{
-			Name:     "CatchallPublicNoAccount",
-			Resource: srvResource,
-			Rules: []*Rule{
-				{
-					Scope:    "",
-					Resource: catchallResource,
-				},
-			},
-		},
-		{
-			Name:     "CatchallPrivateAccount",
-			Account:  &Account{},
-			Resource: srvResource,
-			Rules: []*Rule{
-				{
-					Scope:    "*",
-					Resource: catchallResource,
-				},
-			},
-		},
-		{
-			Name:     "CatchallPrivateNoAccount",
-			Resource: srvResource,
-			Rules: []*Rule{
-				{
-					Scope:    "*",
-					Resource: catchallResource,
-				},
-			},
-			Error: ErrForbidden,
-		},
-		{
-			Name:     "CatchallServiceRuleMatch",
-			Resource: srvResource,
-			Account:  &Account{},
-			Rules: []*Rule{
-				{
-					Scope: "*",
-					Resource: &Resource{
-						Type:     srvResource.Type,
-						Name:     srvResource.Name,
-						Endpoint: "*",
-					},
-				},
-			},
-		},
-		{
-			Name:     "CatchallServiceRuleNoMatch",
-			Resource: srvResource,
-			Account:  &Account{},
-			Rules: []*Rule{
-				{
-					Scope: "*",
-					Resource: &Resource{
-						Type:     srvResource.Type,
-						Name:     "wrongname",
-						Endpoint: "*",
-					},
-				},
-			},
-			Error: ErrForbidden,
-		},
-		{
-			Name:     "ExactRuleValidScope",
-			Resource: srvResource,
-			Account: &Account{
-				Scopes: []string{"neededscope"},
-			},
-			Rules: []*Rule{
-				{
-					Scope:    "neededscope",
-					Resource: srvResource,
-				},
-			},
-		},
-		{
-			Name:     "ExactRuleInvalidScope",
-			Resource: srvResource,
-			Account: &Account{
-				Scopes: []string{"neededscope"},
-			},
-			Rules: []*Rule{
-				{
-					Scope:    "invalidscope",
-					Resource: srvResource,
-				},
-			},
-			Error: ErrForbidden,
-		},
-		{
-			Name:     "CatchallDenyWithAccount",
-			Resource: srvResource,
-			Account:  &Account{},
-			Rules: []*Rule{
-				{
-					Scope:    "*",
-					Resource: catchallResource,
-					Access:   AccessDenied,
-				},
-			},
-			Error: ErrForbidden,
-		},
-		{
-			Name:     "CatchallDenyWithNoAccount",
-			Resource: srvResource,
-			Account:  &Account{},
-			Rules: []*Rule{
-				{
-					Scope:    "*",
-					Resource: catchallResource,
-					Access:   AccessDenied,
-				},
-			},
-			Error: ErrForbidden,
-		},
-		{
-			Name:     "RulePriorityGrantFirst",
-			Resource: srvResource,
-			Account:  &Account{},
-			Rules: []*Rule{
-				{
-					Scope:    "*",
-					Resource: catchallResource,
-					Access:   AccessGranted,
-					Priority: 1,
-				},
-				{
-					Scope:    "*",
-					Resource: catchallResource,
-					Access:   AccessDenied,
-					Priority: 0,
-				},
-			},
-		},
-		{
-			Name:     "RulePriorityDenyFirst",
-			Resource: srvResource,
-			Account:  &Account{},
-			Rules: []*Rule{
-				{
-					Scope:    "*",
-					Resource: catchallResource,
-					Access:   AccessGranted,
-					Priority: 0,
-				},
-				{
-					Scope:    "*",
-					Resource: catchallResource,
-					Access:   AccessDenied,
-					Priority: 1,
-				},
-			},
-			Error: ErrForbidden,
-		},
-		{
-			Name:     "WebExactEndpointValid",
-			Resource: webResource,
-			Account:  &Account{},
-			Rules: []*Rule{
-				{
-					Scope:    "*",
-					Resource: webResource,
-				},
-			},
-		},
-		{
-			Name:     "WebExactEndpointInalid",
-			Resource: webResource,
-			Account:  &Account{},
-			Rules: []*Rule{
-				{
-					Scope: "*",
-					Resource: &Resource{
-						Type:     webResource.Type,
-						Name:     webResource.Name,
-						Endpoint: "invalidendpoint",
-					},
-				},
-			},
-			Error: ErrForbidden,
-		},
-		{
-			Name:     "WebWildcardEndpoint",
-			Resource: webResource,
-			Account:  &Account{},
-			Rules: []*Rule{
-				{
-					Scope: "*",
-					Resource: &Resource{
-						Type:     webResource.Type,
-						Name:     webResource.Name,
-						Endpoint: "*",
-					},
-				},
-			},
-		},
-		{
-			Name:     "WebWildcardPathEndpointValid",
-			Resource: webResource,
-			Account:  &Account{},
-			Rules: []*Rule{
-				{
-					Scope: "*",
-					Resource: &Resource{
-						Type:     webResource.Type,
-						Name:     webResource.Name,
-						Endpoint: "/foo/*",
-					},
-				},
-			},
-		},
-		{
-			Name:     "WebWildcardPathEndpointInvalid",
-			Resource: webResource,
-			Account:  &Account{},
-			Rules: []*Rule{
-				{
-					Scope: "*",
-					Resource: &Resource{
-						Type:     webResource.Type,
-						Name:     webResource.Name,
-						Endpoint: "/bar/*",
-					},
-				},
-			},
-			Error: ErrForbidden,
-		},
-	}
-
-	for _, tc := range tt {
-		t.Run(tc.Name, func(t *testing.T) {
-			if err := VerifyAccess(tc.Rules, tc.Account, tc.Resource); err != tc.Error {
-				t.Errorf("Expected %v but got %v", tc.Error, err)
-			}
-		})
-	}
-}

broker/broker.go

@@ -4,8 +4,10 @@ package broker
 import (
 	"context"
 	"errors"
+	"time"
 
-	"github.com/unistack-org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/metadata"
 )
 
 // DefaultBroker default memory broker
@@ -16,6 +18,12 @@ var (
 	ErrNotConnected = errors.New("broker not connected")
 	// ErrDisconnected returns when broker disconnected
 	ErrDisconnected = errors.New("broker disconnected")
+	// ErrInvalidMessage returns when invalid Message passed
+	ErrInvalidMessage = errors.New("invalid message")
+	// ErrInvalidHandler returns when subscriber passed to Subscribe
+	ErrInvalidHandler = errors.New("invalid handler, ony func(Message) error and func([]Message) error supported")
+	// DefaultGracefulTimeout
+	DefaultGracefulTimeout = 5 * time.Second
 )
 
 // Broker is an interface used for asynchronous messaging.
@@ -32,91 +40,44 @@ type Broker interface {
 	Connect(ctx context.Context) error
 	// Disconnect disconnect from broker
 	Disconnect(ctx context.Context) error
+	// NewMessage create new broker message to publish.
+	NewMessage(ctx context.Context, hdr metadata.Metadata, body interface{}, opts ...PublishOption) (Message, error)
 	// Publish message to broker topic
-	Publish(ctx context.Context, topic string, msg *Message, opts ...PublishOption) error
+	Publish(ctx context.Context, topic string, messages ...Message) error
 	// Subscribe subscribes to topic message via handler
-	Subscribe(ctx context.Context, topic string, h Handler, opts ...SubscribeOption) (Subscriber, error)
-	// BatchPublish messages to broker with multiple topics
-	BatchPublish(ctx context.Context, msgs []*Message, opts ...PublishOption) error
-	// BatchSubscribe subscribes to topic messages via handler
-	BatchSubscribe(ctx context.Context, topic string, h BatchHandler, opts ...SubscribeOption) (Subscriber, error)
+	Subscribe(ctx context.Context, topic string, handler interface{}, opts ...SubscribeOption) (Subscriber, error)
 	// String type of broker
 	String() string
+	// Live returns broker liveness
+	Live() bool
+	// Ready returns broker readiness
+	Ready() bool
+	// Health returns broker health
+	Health() bool
 }
 
-// Handler is used to process messages via a subscription of a topic.
-type Handler func(Event) error
+type (
+	FuncPublish   func(ctx context.Context, topic string, messages ...Message) error
+	HookPublish   func(next FuncPublish) FuncPublish
+	FuncSubscribe func(ctx context.Context, topic string, handler interface{}, opts ...SubscribeOption) (Subscriber, error)
+	HookSubscribe func(next FuncSubscribe) FuncSubscribe
+)
 
-// Events contains multiple events
-type Events []Event
-
-func (evs Events) Ack() error {
-	var err error
-	for _, ev := range evs {
-		if err = ev.Ack(); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-func (evs Events) SetError(err error) {
-	for _, ev := range evs {
-		ev.SetError(err)
-	}
-}
-
-// BatchHandler is used to process messages in batches via a subscription of a topic.
-type BatchHandler func(Events) error
-
-// Event is given to a subscription handler for processing
-type Event interface {
-	// Topic returns event topic
+// Message is given to a subscription handler for processing
+type Message interface {
+	// Context for the message.
+	Context() context.Context
+	// Topic returns message destination topic.
 	Topic() string
-	// Message returns broker message
-	Message() *Message
-	// Ack acknowledge message
+	// Header returns message headers.
+	Header() metadata.Metadata
+	// Body returns broker message []byte slice
+	Body() []byte
+	// Unmarshal try to decode message body to dst.
+	// This is helper method that uses codec.Unmarshal.
+	Unmarshal(dst interface{}, opts ...codec.Option) error
+	// Ack acknowledge message if supported.
 	Ack() error
-	// Error returns message error (like decoding errors or some other)
-	Error() error
-	// SetError set event processing error
-	SetError(err error)
-}
-
-// RawMessage is a raw encoded JSON value.
-// It implements Marshaler and Unmarshaler and can be used to delay decoding or precompute a encoding.
-type RawMessage []byte
-
-// MarshalJSON returns m as the JSON encoding of m.
-func (m *RawMessage) MarshalJSON() ([]byte, error) {
-	if m == nil {
-		return []byte("null"), nil
-	}
-	return *m, nil
-}
-
-// UnmarshalJSON sets *m to a copy of data.
-func (m *RawMessage) UnmarshalJSON(data []byte) error {
-	if m == nil {
-		return errors.New("RawMessage UnmarshalJSON on nil pointer")
-	}
-	*m = append((*m)[0:0], data...)
-	return nil
-}
-
-// Message is used to transfer data
-type Message struct {
-	// Header contains message metadata
-	Header metadata.Metadata
-	// Body contains message body
-	Body RawMessage
-}
-
-// NewMessage create broker message with topic filled
-func NewMessage(topic string) *Message {
-	m := &Message{Header: metadata.New(2)}
-	m.Header.Set(metadata.HeaderTopic, topic)
-	return m
 }
 
 // Subscriber is a convenience return type for the Subscribe method

broker/context.go

@@ -15,6 +15,15 @@ func FromContext(ctx context.Context) (Broker, bool) {
 	return c, ok
 }
 
+// MustContext returns broker from passed context
+func MustContext(ctx context.Context) Broker {
+	b, ok := FromContext(ctx)
+	if !ok {
+		panic("missing broker")
+	}
+	return b
+}
+
 // NewContext savess broker in context
 func NewContext(ctx context.Context, s Broker) context.Context {
 	if ctx == nil {
@@ -33,16 +42,6 @@ func SetSubscribeOption(k, v interface{}) SubscribeOption {
 	}
 }
 
-// SetOption returns a function to setup a context with given value
-func SetOption(k, v interface{}) Option {
-	return func(o *Options) {
-		if o.Context == nil {
-			o.Context = context.Background()
-		}
-		o.Context = context.WithValue(o.Context, k, v)
-	}
-}
-
 // SetPublishOption returns a function to setup a context with given value
 func SetPublishOption(k, v interface{}) PublishOption {
 	return func(o *PublishOptions) {
@@ -52,3 +51,13 @@ func SetPublishOption(k, v interface{}) PublishOption {
 		o.Context = context.WithValue(o.Context, k, v)
 	}
 }
+
+// SetOption returns a function to setup a context with given value
+func SetOption(k, v interface{}) Option {
+	return func(o *Options) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, k, v)
+	}
+}

broker/context_test.go

@@ -0,0 +1,61 @@
+package broker
+
+import (
+	"context"
+	"testing"
+)
+
+func TestFromContext(t *testing.T) {
+	ctx := context.WithValue(context.TODO(), brokerKey{}, NewBroker())
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("FromContext not works")
+	}
+}
+
+func TestFromNilContext(t *testing.T) {
+	// nolint: staticcheck
+	c, ok := FromContext(nil)
+	if ok || c != nil {
+		t.Fatal("FromContext not works")
+	}
+}
+
+func TestNewContext(t *testing.T) {
+	ctx := NewContext(context.TODO(), NewBroker())
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("NewContext not works")
+	}
+}
+
+func TestNewNilContext(t *testing.T) {
+	// nolint: staticcheck
+	ctx := NewContext(nil, NewBroker())
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("NewContext not works")
+	}
+}
+
+func TestSetSubscribeOption(t *testing.T) {
+	type key struct{}
+	o := SetSubscribeOption(key{}, "test")
+	opts := &SubscribeOptions{}
+	o(opts)
+
+	if v, ok := opts.Context.Value(key{}).(string); !ok || v == "" {
+		t.Fatal("SetSubscribeOption not works")
+	}
+}
+
+func TestSetOption(t *testing.T) {
+	type key struct{}
+	o := SetOption(key{}, "test")
+	opts := &Options{}
+	o(opts)
+
+	if v, ok := opts.Context.Value(key{}).(string); !ok || v == "" {
+		t.Fatal("SetOption not works")
+	}
+}

broker/memory.go

@@ -1,370 +0,0 @@
-package broker
-
-import (
-	"context"
-	"sync"
-
-	"github.com/google/uuid"
-	"github.com/unistack-org/micro/v3/logger"
-	"github.com/unistack-org/micro/v3/metadata"
-	maddr "github.com/unistack-org/micro/v3/util/addr"
-	mnet "github.com/unistack-org/micro/v3/util/net"
-	"github.com/unistack-org/micro/v3/util/rand"
-)
-
-type memoryBroker struct {
-	subscribers map[string][]*memorySubscriber
-	addr        string
-	opts        Options
-	sync.RWMutex
-	connected bool
-}
-
-type memoryEvent struct {
-	err     error
-	message interface{}
-	topic   string
-	opts    Options
-}
-
-type memorySubscriber struct {
-	ctx          context.Context
-	exit         chan bool
-	handler      Handler
-	batchhandler BatchHandler
-	id           string
-	topic        string
-	opts         SubscribeOptions
-}
-
-func (m *memoryBroker) Options() Options {
-	return m.opts
-}
-
-func (m *memoryBroker) Address() string {
-	return m.addr
-}
-
-func (m *memoryBroker) Connect(ctx context.Context) error {
-	m.Lock()
-	defer m.Unlock()
-
-	if m.connected {
-		return nil
-	}
-
-	// use 127.0.0.1 to avoid scan of all network interfaces
-	addr, err := maddr.Extract("127.0.0.1")
-	if err != nil {
-		return err
-	}
-	var rng rand.Rand
-	i := rng.Intn(20000)
-	// set addr with port
-	addr = mnet.HostPort(addr, 10000+i)
-
-	m.addr = addr
-	m.connected = true
-
-	return nil
-}
-
-func (m *memoryBroker) Disconnect(ctx context.Context) error {
-	m.Lock()
-	defer m.Unlock()
-
-	if !m.connected {
-		return nil
-	}
-
-	m.connected = false
-	return nil
-}
-
-func (m *memoryBroker) Init(opts ...Option) error {
-	for _, o := range opts {
-		o(&m.opts)
-	}
-	return nil
-}
-
-func (m *memoryBroker) Publish(ctx context.Context, topic string, msg *Message, opts ...PublishOption) error {
-	m.RLock()
-	if !m.connected {
-		m.RUnlock()
-		return ErrNotConnected
-	}
-	m.RUnlock()
-
-	options := NewPublishOptions(opts...)
-	vs := make([]msgWrapper, 0, 1)
-	if m.opts.Codec == nil || options.BodyOnly {
-		topic, _ := msg.Header.Get(metadata.HeaderTopic)
-		vs = append(vs, msgWrapper{topic: topic, body: msg})
-	} else {
-		topic, _ := msg.Header.Get(metadata.HeaderTopic)
-		buf, err := m.opts.Codec.Marshal(msg)
-		if err != nil {
-			return err
-		}
-		vs = append(vs, msgWrapper{topic: topic, body: buf})
-	}
-
-	return m.publish(ctx, vs, opts...)
-}
-
-type msgWrapper struct {
-	topic string
-	body  interface{}
-}
-
-func (m *memoryBroker) BatchPublish(ctx context.Context, msgs []*Message, opts ...PublishOption) error {
-	m.RLock()
-	if !m.connected {
-		m.RUnlock()
-		return ErrNotConnected
-	}
-	m.RUnlock()
-
-	options := NewPublishOptions(opts...)
-	vs := make([]msgWrapper, 0, len(msgs))
-	if m.opts.Codec == nil || options.BodyOnly {
-		for _, msg := range msgs {
-			topic, _ := msg.Header.Get(metadata.HeaderTopic)
-			vs = append(vs, msgWrapper{topic: topic, body: msg})
-		}
-	} else {
-		for _, msg := range msgs {
-			topic, _ := msg.Header.Get(metadata.HeaderTopic)
-			buf, err := m.opts.Codec.Marshal(msg)
-			if err != nil {
-				return err
-			}
-			vs = append(vs, msgWrapper{topic: topic, body: buf})
-		}
-	}
-
-	return m.publish(ctx, vs, opts...)
-}
-
-func (m *memoryBroker) publish(ctx context.Context, vs []msgWrapper, opts ...PublishOption) error {
-	var err error
-
-	msgTopicMap := make(map[string]Events)
-	for _, v := range vs {
-		p := &memoryEvent{
-			topic:   v.topic,
-			message: v.body,
-			opts:    m.opts,
-		}
-		msgTopicMap[p.topic] = append(msgTopicMap[p.topic], p)
-	}
-
-	beh := m.opts.BatchErrorHandler
-	eh := m.opts.ErrorHandler
-
-	for t, ms := range msgTopicMap {
-		m.RLock()
-		subs, ok := m.subscribers[t]
-		m.RUnlock()
-		if !ok {
-			continue
-		}
-
-		for _, sub := range subs {
-			// batch processing
-			if sub.batchhandler != nil {
-				if err = sub.batchhandler(ms); err != nil {
-					ms.SetError(err)
-					if sub.opts.BatchErrorHandler != nil {
-						beh = sub.opts.BatchErrorHandler
-					}
-					if beh != nil {
-						beh(ms)
-					} else if m.opts.Logger.V(logger.ErrorLevel) {
-						m.opts.Logger.Error(m.opts.Context, err.Error())
-					}
-				} else if sub.opts.AutoAck {
-					if err = ms.Ack(); err != nil {
-						m.opts.Logger.Errorf(m.opts.Context, "ack failed: %v", err)
-					}
-				}
-			}
-			// single processing
-			if sub.handler != nil {
-				for _, p := range ms {
-					if err = sub.handler(p); err != nil {
-						p.SetError(err)
-						if sub.opts.ErrorHandler != nil {
-							eh = sub.opts.ErrorHandler
-						}
-						if eh != nil {
-							eh(p)
-						} else if m.opts.Logger.V(logger.ErrorLevel) {
-							m.opts.Logger.Error(m.opts.Context, err.Error())
-						}
-					} else if sub.opts.AutoAck {
-						if err = p.Ack(); err != nil {
-							m.opts.Logger.Errorf(m.opts.Context, "ack failed: %v", err)
-						}
-					}
-				}
-			}
-		}
-	}
-
-	return nil
-}
-
-func (m *memoryBroker) BatchSubscribe(ctx context.Context, topic string, handler BatchHandler, opts ...SubscribeOption) (Subscriber, error) {
-	m.RLock()
-	if !m.connected {
-		m.RUnlock()
-		return nil, ErrNotConnected
-	}
-	m.RUnlock()
-
-	id, err := uuid.NewRandom()
-	if err != nil {
-		return nil, err
-	}
-
-	options := NewSubscribeOptions(opts...)
-
-	sub := &memorySubscriber{
-		exit:         make(chan bool, 1),
-		id:           id.String(),
-		topic:        topic,
-		batchhandler: handler,
-		opts:         options,
-		ctx:          ctx,
-	}
-
-	m.Lock()
-	m.subscribers[topic] = append(m.subscribers[topic], sub)
-	m.Unlock()
-
-	go func() {
-		<-sub.exit
-		m.Lock()
-		newSubscribers := make([]*memorySubscriber, 0, len(m.subscribers)-1)
-		for _, sb := range m.subscribers[topic] {
-			if sb.id == sub.id {
-				continue
-			}
-			newSubscribers = append(newSubscribers, sb)
-		}
-		m.subscribers[topic] = newSubscribers
-		m.Unlock()
-	}()
-
-	return sub, nil
-}
-
-func (m *memoryBroker) Subscribe(ctx context.Context, topic string, handler Handler, opts ...SubscribeOption) (Subscriber, error) {
-	m.RLock()
-	if !m.connected {
-		m.RUnlock()
-		return nil, ErrNotConnected
-	}
-	m.RUnlock()
-
-	id, err := uuid.NewRandom()
-	if err != nil {
-		return nil, err
-	}
-
-	options := NewSubscribeOptions(opts...)
-
-	sub := &memorySubscriber{
-		exit:    make(chan bool, 1),
-		id:      id.String(),
-		topic:   topic,
-		handler: handler,
-		opts:    options,
-		ctx:     ctx,
-	}
-
-	m.Lock()
-	m.subscribers[topic] = append(m.subscribers[topic], sub)
-	m.Unlock()
-
-	go func() {
-		<-sub.exit
-		m.Lock()
-		newSubscribers := make([]*memorySubscriber, 0, len(m.subscribers)-1)
-		for _, sb := range m.subscribers[topic] {
-			if sb.id == sub.id {
-				continue
-			}
-			newSubscribers = append(newSubscribers, sb)
-		}
-		m.subscribers[topic] = newSubscribers
-		m.Unlock()
-	}()
-
-	return sub, nil
-}
-
-func (m *memoryBroker) String() string {
-	return "memory"
-}
-
-func (m *memoryBroker) Name() string {
-	return m.opts.Name
-}
-
-func (m *memoryEvent) Topic() string {
-	return m.topic
-}
-
-func (m *memoryEvent) Message() *Message {
-	switch v := m.message.(type) {
-	case *Message:
-		return v
-	case []byte:
-		msg := &Message{}
-		if err := m.opts.Codec.Unmarshal(v, msg); err != nil {
-			if m.opts.Logger.V(logger.ErrorLevel) {
-				m.opts.Logger.Error(m.opts.Context, "[memory]: failed to unmarshal: %v", err)
-			}
-			return nil
-		}
-		return msg
-	}
-
-	return nil
-}
-
-func (m *memoryEvent) Ack() error {
-	return nil
-}
-
-func (m *memoryEvent) Error() error {
-	return m.err
-}
-
-func (m *memoryEvent) SetError(err error) {
-	m.err = err
-}
-
-func (m *memorySubscriber) Options() SubscribeOptions {
-	return m.opts
-}
-
-func (m *memorySubscriber) Topic() string {
-	return m.topic
-}
-
-func (m *memorySubscriber) Unsubscribe(ctx context.Context) error {
-	m.exit <- true
-	return nil
-}
-
-// NewBroker return new memory broker
-func NewBroker(opts ...Option) Broker {
-	return &memoryBroker{
-		opts:        NewOptions(opts...),
-		subscribers: make(map[string][]*memorySubscriber),
-	}
-}

broker/memory/memory.go

@@ -0,0 +1,338 @@
+package broker
+
+import (
+	"context"
+	"strings"
+	"sync"
+
+	"go.unistack.org/micro/v4/broker"
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/logger"
+	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v4/options"
+	maddr "go.unistack.org/micro/v4/util/addr"
+	"go.unistack.org/micro/v4/util/id"
+	mnet "go.unistack.org/micro/v4/util/net"
+	"go.unistack.org/micro/v4/util/rand"
+)
+
+type Broker struct {
+	funcPublish   broker.FuncPublish
+	funcSubscribe broker.FuncSubscribe
+	subscribers   map[string][]*Subscriber
+	addr          string
+	opts          broker.Options
+	sync.RWMutex
+	connected bool
+}
+
+type memoryMessage struct {
+	c     codec.Codec
+	topic string
+	ctx   context.Context
+	body  []byte
+	hdr   metadata.Metadata
+	opts  broker.PublishOptions
+}
+
+func (m *memoryMessage) Ack() error {
+	return nil
+}
+
+func (m *memoryMessage) Body() []byte {
+	return m.body
+}
+
+func (m *memoryMessage) Header() metadata.Metadata {
+	return m.hdr
+}
+
+func (m *memoryMessage) Context() context.Context {
+	return m.ctx
+}
+
+func (m *memoryMessage) Topic() string {
+	return ""
+}
+
+func (m *memoryMessage) Unmarshal(dst interface{}, opts ...codec.Option) error {
+	return m.c.Unmarshal(m.body, dst)
+}
+
+type Subscriber struct {
+	ctx     context.Context
+	exit    chan bool
+	handler interface{}
+	id      string
+	topic   string
+	opts    broker.SubscribeOptions
+}
+
+func (b *Broker) newCodec(ct string) (codec.Codec, error) {
+	if idx := strings.IndexRune(ct, ';'); idx >= 0 {
+		ct = ct[:idx]
+	}
+	b.RLock()
+	c, ok := b.opts.Codecs[ct]
+	b.RUnlock()
+	if ok {
+		return c, nil
+	}
+	return nil, codec.ErrUnknownContentType
+}
+
+func (b *Broker) Options() broker.Options {
+	return b.opts
+}
+
+func (b *Broker) Address() string {
+	return b.addr
+}
+
+func (b *Broker) Connect(ctx context.Context) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+
+	b.Lock()
+	defer b.Unlock()
+
+	if b.connected {
+		return nil
+	}
+
+	// use 127.0.0.1 to avoid scan of all network interfaces
+	addr, err := maddr.Extract("127.0.0.1")
+	if err != nil {
+		return err
+	}
+	var rng rand.Rand
+	i := rng.Intn(20000)
+	// set addr with port
+	addr = mnet.HostPort(addr, 10000+i)
+
+	b.addr = addr
+	b.connected = true
+
+	return nil
+}
+
+func (b *Broker) Disconnect(ctx context.Context) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+
+	b.Lock()
+	defer b.Unlock()
+
+	if !b.connected {
+		return nil
+	}
+
+	b.connected = false
+	return nil
+}
+
+func (b *Broker) Init(opts ...broker.Option) error {
+	for _, o := range opts {
+		o(&b.opts)
+	}
+
+	b.funcPublish = b.fnPublish
+	b.funcSubscribe = b.fnSubscribe
+
+	b.opts.Hooks.EachPrev(func(hook options.Hook) {
+		switch h := hook.(type) {
+		case broker.HookPublish:
+			b.funcPublish = h(b.funcPublish)
+		case broker.HookSubscribe:
+			b.funcSubscribe = h(b.funcSubscribe)
+		}
+	})
+
+	return nil
+}
+
+func (b *Broker) NewMessage(ctx context.Context, hdr metadata.Metadata, body interface{}, opts ...broker.PublishOption) (broker.Message, error) {
+	options := broker.NewPublishOptions(opts...)
+	m := &memoryMessage{ctx: ctx, hdr: hdr, opts: options}
+	c, err := b.newCodec(m.opts.ContentType)
+	if err == nil {
+		m.body, err = c.Marshal(body)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return m, nil
+}
+
+func (b *Broker) Publish(ctx context.Context, topic string, messages ...broker.Message) error {
+	return b.funcPublish(ctx, topic, messages...)
+}
+
+func (b *Broker) fnPublish(ctx context.Context, topic string, messages ...broker.Message) error {
+	return b.publish(ctx, topic, messages...)
+}
+
+func (b *Broker) publish(ctx context.Context, topic string, messages ...broker.Message) error {
+	b.RLock()
+	if !b.connected {
+		b.RUnlock()
+		return broker.ErrNotConnected
+	}
+	b.RUnlock()
+
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	default:
+	}
+
+	b.RLock()
+	subs, ok := b.subscribers[topic]
+	b.RUnlock()
+	if !ok {
+		return nil
+	}
+
+	var err error
+
+	for _, sub := range subs {
+		switch s := sub.handler.(type) {
+		default:
+			if b.opts.Logger.V(logger.ErrorLevel) {
+				b.opts.Logger.Error(ctx, "broker  handler error", broker.ErrInvalidHandler)
+			}
+		case func(broker.Message) error:
+			for _, message := range messages {
+				msg, ok := message.(*memoryMessage)
+				if !ok {
+					if b.opts.Logger.V(logger.ErrorLevel) {
+						b.opts.Logger.Error(ctx, "broker handler error", broker.ErrInvalidMessage)
+					}
+				}
+				msg.topic = topic
+				if err = s(msg); err == nil && sub.opts.AutoAck {
+					err = msg.Ack()
+				}
+				if err != nil {
+					if b.opts.Logger.V(logger.ErrorLevel) {
+						b.opts.Logger.Error(ctx, "broker handler error", err)
+					}
+				}
+			}
+		case func([]broker.Message) error:
+			if err = s(messages); err == nil && sub.opts.AutoAck {
+				for _, message := range messages {
+					err = message.Ack()
+					if err != nil {
+						if b.opts.Logger.V(logger.ErrorLevel) {
+							b.opts.Logger.Error(ctx, "broker handler error", err)
+						}
+					}
+				}
+			}
+		}
+	}
+
+	return nil
+}
+
+func (b *Broker) Subscribe(ctx context.Context, topic string, handler interface{}, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
+	return b.funcSubscribe(ctx, topic, handler, opts...)
+}
+
+func (b *Broker) fnSubscribe(ctx context.Context, topic string, handler interface{}, opts ...broker.SubscribeOption) (broker.Subscriber, error) {
+	if err := broker.IsValidHandler(handler); err != nil {
+		return nil, err
+	}
+
+	b.RLock()
+	if !b.connected {
+		b.RUnlock()
+		return nil, broker.ErrNotConnected
+	}
+	b.RUnlock()
+
+	sid, err := id.New()
+	if err != nil {
+		return nil, err
+	}
+
+	options := broker.NewSubscribeOptions(opts...)
+
+	sub := &Subscriber{
+		exit:    make(chan bool, 1),
+		id:      sid,
+		topic:   topic,
+		handler: handler,
+		opts:    options,
+		ctx:     ctx,
+	}
+
+	b.Lock()
+	b.subscribers[topic] = append(b.subscribers[topic], sub)
+	b.Unlock()
+
+	go func() {
+		<-sub.exit
+		b.Lock()
+		newSubscribers := make([]*Subscriber, 0, len(b.subscribers)-1)
+		for _, sb := range b.subscribers[topic] {
+			if sb.id == sub.id {
+				continue
+			}
+			newSubscribers = append(newSubscribers, sb)
+		}
+		b.subscribers[topic] = newSubscribers
+		b.Unlock()
+	}()
+
+	return sub, nil
+}
+
+func (b *Broker) String() string {
+	return "memory"
+}
+
+func (b *Broker) Name() string {
+	return b.opts.Name
+}
+
+func (b *Broker) Live() bool {
+	return true
+}
+
+func (b *Broker) Ready() bool {
+	return true
+}
+
+func (b *Broker) Health() bool {
+	return true
+}
+
+func (m *Subscriber) Options() broker.SubscribeOptions {
+	return m.opts
+}
+
+func (m *Subscriber) Topic() string {
+	return m.topic
+}
+
+func (m *Subscriber) Unsubscribe(ctx context.Context) error {
+	m.exit <- true
+	return nil
+}
+
+// NewBroker return new memory broker
+func NewBroker(opts ...broker.Option) broker.Broker {
+	return &Broker{
+		opts:        broker.NewOptions(opts...),
+		subscribers: make(map[string][]*Subscriber),
+	}
+}

broker/memory/memory_test.go

@@ -0,0 +1,74 @@
+package broker
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"go.uber.org/atomic"
+	"go.unistack.org/micro/v4/broker"
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/metadata"
+)
+
+type hldr struct {
+	c atomic.Int64
+}
+
+func (h *hldr) Handler(m broker.Message) error {
+	h.c.Add(1)
+	return nil
+}
+
+func TestMemoryBroker(t *testing.T) {
+	b := NewBroker(broker.Codec("application/octet-stream", codec.NewCodec()))
+	ctx := context.Background()
+
+	if err := b.Init(); err != nil {
+		t.Fatalf("Unexpected init error %v", err)
+	}
+
+	if err := b.Connect(ctx); err != nil {
+		t.Fatalf("Unexpected connect error %v", err)
+	}
+
+	topic := "test"
+	count := int64(10)
+
+	h := &hldr{}
+
+	sub, err := b.Subscribe(ctx, topic, h.Handler)
+	if err != nil {
+		t.Fatalf("Unexpected error subscribing %v", err)
+	}
+
+	for i := int64(0); i < count; i++ {
+		message, err := b.NewMessage(ctx,
+			metadata.Pairs(
+				"foo", "bar",
+				"id", fmt.Sprintf("%d", i),
+			),
+			[]byte(`"hello world"`),
+			broker.PublishContentType("application/octet-stream"),
+		)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if err := b.Publish(ctx, topic, message); err != nil {
+			t.Fatalf("Unexpected error publishing %d err: %v", i, err)
+		}
+	}
+
+	if err := sub.Unsubscribe(ctx); err != nil {
+		t.Fatalf("Unexpected error unsubscribing from %s: %v", topic, err)
+	}
+
+	if err := b.Disconnect(ctx); err != nil {
+		t.Fatalf("Unexpected connect error %v", err)
+	}
+
+	if h.c.Load() != count {
+		t.Fatal("invalid messages count received")
+	}
+}

broker/memory_test.go

@@ -1,104 +0,0 @@
-package broker
-
-import (
-	"context"
-	"fmt"
-	"testing"
-
-	"github.com/unistack-org/micro/v3/metadata"
-)
-
-func TestMemoryBatchBroker(t *testing.T) {
-	b := NewBroker()
-	ctx := context.Background()
-
-	if err := b.Connect(ctx); err != nil {
-		t.Fatalf("Unexpected connect error %v", err)
-	}
-
-	topic := "test"
-	count := 10
-
-	fn := func(evts Events) error {
-		return evts.Ack()
-	}
-
-	sub, err := b.BatchSubscribe(ctx, topic, fn)
-	if err != nil {
-		t.Fatalf("Unexpected error subscribing %v", err)
-	}
-
-	msgs := make([]*Message, 0, 0)
-	for i := 0; i < count; i++ {
-		message := &Message{
-			Header: map[string]string{
-				metadata.HeaderTopic: topic,
-				"foo":                "bar",
-				"id":                 fmt.Sprintf("%d", i),
-			},
-			Body: []byte(`"hello world"`),
-		}
-		msgs = append(msgs, message)
-	}
-
-	if err := b.BatchPublish(ctx, msgs); err != nil {
-		t.Fatalf("Unexpected error publishing %v", err)
-	}
-
-	if err := sub.Unsubscribe(ctx); err != nil {
-		t.Fatalf("Unexpected error unsubscribing from %s: %v", topic, err)
-	}
-
-	if err := b.Disconnect(ctx); err != nil {
-		t.Fatalf("Unexpected connect error %v", err)
-	}
-}
-func TestMemoryBroker(t *testing.T) {
-	b := NewBroker()
-	ctx := context.Background()
-
-	if err := b.Connect(ctx); err != nil {
-		t.Fatalf("Unexpected connect error %v", err)
-	}
-
-	topic := "test"
-	count := 10
-
-	fn := func(p Event) error {
-		return nil
-	}
-
-	sub, err := b.Subscribe(ctx, topic, fn)
-	if err != nil {
-		t.Fatalf("Unexpected error subscribing %v", err)
-	}
-
-	msgs := make([]*Message, 0, 0)
-	for i := 0; i < count; i++ {
-		message := &Message{
-			Header: map[string]string{
-				metadata.HeaderTopic: topic,
-				"foo":                "bar",
-				"id":                 fmt.Sprintf("%d", i),
-			},
-			Body: []byte(`"hello world"`),
-		}
-		msgs = append(msgs, message)
-
-		if err := b.Publish(ctx, topic, message); err != nil {
-			t.Fatalf("Unexpected error publishing %d err: %v", i, err)
-		}
-	}
-
-	if err := b.BatchPublish(ctx, msgs); err != nil {
-		t.Fatalf("Unexpected error publishing %v", err)
-	}
-
-	if err := sub.Unsubscribe(ctx); err != nil {
-		t.Fatalf("Unexpected error unsubscribing from %s: %v", topic, err)
-	}
-
-	if err := b.Disconnect(ctx); err != nil {
-		t.Fatalf("Unexpected connect error %v", err)
-	}
-}

broker/noop.go

@@ -0,0 +1,176 @@
+package broker
+
+import (
+	"context"
+	"strings"
+	"sync"
+
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v4/options"
+)
+
+type NoopBroker struct {
+	funcPublish   FuncPublish
+	funcSubscribe FuncSubscribe
+	opts          Options
+	sync.RWMutex
+}
+
+func (b *NoopBroker) newCodec(ct string) (codec.Codec, error) {
+	if idx := strings.IndexRune(ct, ';'); idx >= 0 {
+		ct = ct[:idx]
+	}
+	b.RLock()
+	c, ok := b.opts.Codecs[ct]
+	b.RUnlock()
+	if ok {
+		return c, nil
+	}
+	return nil, codec.ErrUnknownContentType
+}
+
+func NewBroker(opts ...Option) *NoopBroker {
+	b := &NoopBroker{opts: NewOptions(opts...)}
+	b.funcPublish = b.fnPublish
+	b.funcSubscribe = b.fnSubscribe
+
+	return b
+}
+
+func (b *NoopBroker) Health() bool {
+	return true
+}
+
+func (b *NoopBroker) Live() bool {
+	return true
+}
+
+func (b *NoopBroker) Ready() bool {
+	return true
+}
+
+func (b *NoopBroker) Name() string {
+	return b.opts.Name
+}
+
+func (b *NoopBroker) String() string {
+	return "noop"
+}
+
+func (b *NoopBroker) Options() Options {
+	return b.opts
+}
+
+func (b *NoopBroker) Init(opts ...Option) error {
+	for _, opt := range opts {
+		opt(&b.opts)
+	}
+
+	b.funcPublish = b.fnPublish
+	b.funcSubscribe = b.fnSubscribe
+
+	b.opts.Hooks.EachPrev(func(hook options.Hook) {
+		switch h := hook.(type) {
+		case HookPublish:
+			b.funcPublish = h(b.funcPublish)
+		case HookSubscribe:
+			b.funcSubscribe = h(b.funcSubscribe)
+		}
+	})
+
+	return nil
+}
+
+func (b *NoopBroker) Connect(_ context.Context) error {
+	return nil
+}
+
+func (b *NoopBroker) Disconnect(_ context.Context) error {
+	return nil
+}
+
+func (b *NoopBroker) Address() string {
+	return strings.Join(b.opts.Addrs, ",")
+}
+
+type noopMessage struct {
+	c    codec.Codec
+	ctx  context.Context
+	body []byte
+	hdr  metadata.Metadata
+	opts PublishOptions
+}
+
+func (m *noopMessage) Ack() error {
+	return nil
+}
+
+func (m *noopMessage) Body() []byte {
+	return m.body
+}
+
+func (m *noopMessage) Header() metadata.Metadata {
+	return m.hdr
+}
+
+func (m *noopMessage) Context() context.Context {
+	return m.ctx
+}
+
+func (m *noopMessage) Topic() string {
+	return ""
+}
+
+func (m *noopMessage) Unmarshal(dst interface{}, opts ...codec.Option) error {
+	return m.c.Unmarshal(m.body, dst)
+}
+
+func (b *NoopBroker) NewMessage(ctx context.Context, hdr metadata.Metadata, body interface{}, opts ...PublishOption) (Message, error) {
+	options := NewPublishOptions(opts...)
+	m := &noopMessage{ctx: ctx, hdr: hdr, opts: options}
+	c, err := b.newCodec(m.opts.ContentType)
+	if err == nil {
+		m.body, err = c.Marshal(body)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	return m, nil
+}
+
+func (b *NoopBroker) fnPublish(_ context.Context, _ string, _ ...Message) error {
+	return nil
+}
+
+func (b *NoopBroker) Publish(ctx context.Context, topic string, msg ...Message) error {
+	return b.funcPublish(ctx, topic, msg...)
+}
+
+type NoopSubscriber struct {
+	ctx     context.Context
+	topic   string
+	handler interface{}
+	opts    SubscribeOptions
+}
+
+func (b *NoopBroker) fnSubscribe(ctx context.Context, topic string, handler interface{}, opts ...SubscribeOption) (Subscriber, error) {
+	return &NoopSubscriber{ctx: ctx, topic: topic, opts: NewSubscribeOptions(opts...), handler: handler}, nil
+}
+
+func (b *NoopBroker) Subscribe(ctx context.Context, topic string, handler interface{}, opts ...SubscribeOption) (Subscriber, error) {
+	return b.funcSubscribe(ctx, topic, handler, opts...)
+}
+
+func (s *NoopSubscriber) Options() SubscribeOptions {
+	return s.opts
+}
+
+func (s *NoopSubscriber) Topic() string {
+	return s.topic
+}
+
+func (s *NoopSubscriber) Unsubscribe(_ context.Context) error {
+	return nil
+}

broker/noop_test.go

@@ -0,0 +1,35 @@
+package broker
+
+import (
+	"context"
+	"testing"
+)
+
+type testHook struct {
+	f bool
+}
+
+func (t *testHook) Publish1(fn FuncPublish) FuncPublish {
+	return func(ctx context.Context, topic string, messages ...Message) error {
+		t.f = true
+		return fn(ctx, topic, messages...)
+	}
+}
+
+func TestNoopHook(t *testing.T) {
+	h := &testHook{}
+
+	b := NewBroker(Hooks(HookPublish(h.Publish1)))
+
+	if err := b.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := b.Publish(context.TODO(), "", nil); err != nil {
+		t.Fatal(err)
+	}
+
+	if !h.f {
+		t.Fatal("hook not works")
+	}
+}

broker/options.go

@@ -5,49 +5,60 @@ import (
 	"crypto/tls"
 	"time"
 
-	"github.com/unistack-org/micro/v3/codec"
-	"github.com/unistack-org/micro/v3/logger"
-	"github.com/unistack-org/micro/v3/meter"
-	"github.com/unistack-org/micro/v3/register"
-	"github.com/unistack-org/micro/v3/tracer"
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/logger"
+	"go.unistack.org/micro/v4/meter"
+	"go.unistack.org/micro/v4/options"
+	"go.unistack.org/micro/v4/register"
+	"go.unistack.org/micro/v4/sync"
+	"go.unistack.org/micro/v4/tracer"
 )
 
 // Options struct
 type Options struct {
+	// Name holds the broker name
+	Name string
+
 	// Tracer used for tracing
 	Tracer tracer.Tracer
 	// Register can be used for clustering
 	Register register.Register
-	// Codec holds the codec for marshal/unmarshal
-	Codec codec.Codec
+	// Codecs holds the codecs for marshal/unmarshal based on content-type
+	Codecs map[string]codec.Codec
 	// Logger used for logging
 	Logger logger.Logger
 	// Meter used for metrics
 	Meter meter.Meter
 	// Context holds external options
 	Context context.Context
+
+	// Wait waits for a collection of goroutines to finish
+	Wait *sync.WaitGroup
 	// TLSConfig holds tls.TLSConfig options
 	TLSConfig *tls.Config
-	// ErrorHandler used when broker can't unmarshal incoming message
-	ErrorHandler Handler
-	// BatchErrorHandler used when broker can't unmashal incoming messages
-	BatchErrorHandler BatchHandler
-	// Name holds the broker name
-	Name string
+
 	// Addrs holds the broker address
 	Addrs []string
+	// Hooks can be run before broker Publish/BatchPublish and
+	// Subscribe/BatchSubscribe methods
+	Hooks options.Hooks
+
+	// GracefulTimeout contains time to wait to finish in flight requests
+	GracefulTimeout time.Duration
 }
 
 // NewOptions create new Options
 func NewOptions(opts ...Option) Options {
 	options := Options{
-		Register: register.DefaultRegister,
-		Logger:   logger.DefaultLogger,
-		Context:  context.Background(),
-		Meter:    meter.DefaultMeter,
-		Codec:    codec.DefaultCodec,
-		Tracer:   tracer.DefaultTracer,
+		Register:        register.DefaultRegister,
+		Logger:          logger.DefaultLogger,
+		Context:         context.Background(),
+		Meter:           meter.DefaultMeter,
+		Codecs:          make(map[string]codec.Codec),
+		Tracer:          tracer.DefaultTracer,
+		GracefulTimeout: DefaultGracefulTimeout,
 	}
+
 	for _, o := range opts {
 		o(&options)
 	}
@@ -63,10 +74,13 @@ func Context(ctx context.Context) Option {
 
 // PublishOptions struct
 type PublishOptions struct {
-	// Context holds external options
-	Context context.Context
-	// BodyOnly flag says the message contains raw body bytes
+	// ContentType for message body
+	ContentType string
+	// BodyOnly flag says the message contains raw body bytes and don't need
+	// codec Marshal method
 	BodyOnly bool
+	// Context holds custom options
+	Context context.Context
 }
 
 // NewPublishOptions creates PublishOptions struct
@@ -84,10 +98,6 @@ func NewPublishOptions(opts ...PublishOption) PublishOptions {
 type SubscribeOptions struct {
 	// Context holds external options
 	Context context.Context
-	// ErrorHandler used when broker can't unmarshal incoming message
-	ErrorHandler Handler
-	// BatchErrorHandler used when broker can't unmashal incoming messages
-	BatchErrorHandler BatchHandler
 	// Group holds consumer group
 	Group string
 	// AutoAck flag specifies auto ack of incoming message when no error happens
@@ -106,6 +116,13 @@ type Option func(*Options)
 // PublishOption func
 type PublishOption func(*PublishOptions)
 
+// PublishContentType sets message content-type that used to Marshal
+func PublishContentType(ct string) PublishOption {
+	return func(o *PublishOptions) {
+		o.ContentType = ct
+	}
+}
+
 // PublishBodyOnly publish only body of the message
 func PublishBodyOnly(b bool) PublishOption {
 	return func(o *PublishOptions) {
@@ -113,13 +130,6 @@ func PublishBodyOnly(b bool) PublishOption {
 	}
 }
 
-// PublishContext sets the context
-func PublishContext(ctx context.Context) PublishOption {
-	return func(o *PublishOptions) {
-		o.Context = ctx
-	}
-}
-
 // Addrs sets the host addresses to be used by the broker
 func Addrs(addrs ...string) Option {
 	return func(o *Options) {
@@ -127,51 +137,10 @@ func Addrs(addrs ...string) Option {
 	}
 }
 
-// Codec sets the codec used for encoding/decoding used where
-// a broker does not support headers
-func Codec(c codec.Codec) Option {
+// Codec sets the codec used for encoding/decoding messages
+func Codec(ct string, c codec.Codec) Option {
 	return func(o *Options) {
-		o.Codec = c
-	}
-}
-
-// ErrorHandler will catch all broker errors that cant be handled
-// in normal way, for example Codec errors
-func ErrorHandler(h Handler) Option {
-	return func(o *Options) {
-		o.ErrorHandler = h
-	}
-}
-
-// BatchErrorHandler will catch all broker errors that cant be handled
-// in normal way, for example Codec errors
-func BatchErrorHandler(h BatchHandler) Option {
-	return func(o *Options) {
-		o.BatchErrorHandler = h
-	}
-}
-
-// SubscribeErrorHandler will catch all broker errors that cant be handled
-// in normal way, for example Codec errors
-func SubscribeErrorHandler(h Handler) SubscribeOption {
-	return func(o *SubscribeOptions) {
-		o.ErrorHandler = h
-	}
-}
-
-// SubscribeBatchErrorHandler will catch all broker errors that cant be handled
-// in normal way, for example Codec errors
-func SubscribeBatchErrorHandler(h BatchHandler) SubscribeOption {
-	return func(o *SubscribeOptions) {
-		o.BatchErrorHandler = h
-	}
-}
-
-// Queue sets the subscribers queue
-// Deprecated
-func Queue(name string) SubscribeOption {
-	return func(o *SubscribeOptions) {
-		o.Group = name
+		o.Codecs[ct] = c
 	}
 }
 
@@ -224,6 +193,13 @@ func Name(n string) Option {
 	}
 }
 
+// Hooks sets hook runs before action
+func Hooks(h ...options.Hook) Option {
+	return func(o *Options) {
+		o.Hooks = append(o.Hooks, h...)
+	}
+}
+
 // SubscribeContext set context
 func SubscribeContext(ctx context.Context) SubscribeOption {
 	return func(o *SubscribeOptions) {
@@ -231,14 +207,6 @@ func SubscribeContext(ctx context.Context) SubscribeOption {
 	}
 }
 
-// DisableAutoAck disables auto ack
-// Deprecated
-func DisableAutoAck() SubscribeOption {
-	return func(o *SubscribeOptions) {
-		o.AutoAck = false
-	}
-}
-
 // SubscribeAutoAck contol auto acking of messages
 // after they have been handled.
 func SubscribeAutoAck(b bool) SubscribeOption {

broker/subscriber.go

@@ -0,0 +1,14 @@
+package broker
+
+// IsValidHandler func signature
+func IsValidHandler(sub interface{}) error {
+	switch sub.(type) {
+	default:
+		return ErrInvalidHandler
+	case func(Message) error:
+		break
+	case func([]Message) error:
+		break
+	}
+	return nil
+}

build/build.go

@@ -1,32 +0,0 @@
-// Package build is for building source into a package
-package build
-
-// Build is an interface for building packages
-type Build interface {
-	// Package builds a package
-	Package(name string, src *Source) (*Package, error)
-	// Remove removes the package
-	Remove(*Package) error
-}
-
-// Source is the source of a build
-type Source struct {
-	// Path to the source if local
-	Path string
-	// Language is the language of code
-	Language string
-	// Location of the source
-	Repository string
-}
-
-// Package is packaged format for source
-type Package struct {
-	// Source of the package
-	Source *Source
-	// Name of the package
-	Name string
-	// Location of the package
-	Path string
-	// Type of package e.g tarball, binary, docker
-	Type string
-}

build/options.go

@@ -1,17 +0,0 @@
-package build
-
-// Options struct
-type Options struct {
-	// local path to download source
-	Path string
-}
-
-// Option func
-type Option func(o *Options)
-
-// Path is the Local path for repository
-func Path(p string) Option {
-	return func(o *Options) {
-		o.Path = p
-	}
-}

client/backoff.go

@@ -2,14 +2,29 @@ package client
 
 import (
 	"context"
+	"math"
 	"time"
 
-	"github.com/unistack-org/micro/v3/util/backoff"
+	"go.unistack.org/micro/v4/util/backoff"
 )
 
 // BackoffFunc is the backoff call func
 type BackoffFunc func(ctx context.Context, req Request, attempts int) (time.Duration, error)
 
-func exponentialBackoff(ctx context.Context, req Request, attempts int) (time.Duration, error) {
+// BackoffExp using exponential backoff func
+func BackoffExp(_ context.Context, _ Request, attempts int) (time.Duration, error) {
 	return backoff.Do(attempts), nil
 }
+
+// BackoffInterval specifies randomization interval for backoff func
+func BackoffInterval(minTime time.Duration, maxTime time.Duration) BackoffFunc {
+	return func(_ context.Context, _ Request, attempts int) (time.Duration, error) {
+		td := time.Duration(math.Pow(float64(attempts), math.E)) * time.Millisecond * 100
+		if td < minTime {
+			return minTime, nil
+		} else if td > maxTime {
+			return maxTime, nil
+		}
+		return td, nil
+	}
+}

client/backoff_test.go

@@ -6,7 +6,7 @@ import (
 	"time"
 )
 
-func TestBackoff(t *testing.T) {
+func TestBackoffExp(t *testing.T) {
 	results := []time.Duration{
 		0 * time.Second,
 		100 * time.Millisecond,
@@ -22,7 +22,7 @@ func TestBackoff(t *testing.T) {
 	}
 
 	for i := 0; i < 5; i++ {
-		d, err := exponentialBackoff(context.TODO(), r, i)
+		d, err := BackoffExp(context.TODO(), r, i)
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -32,3 +32,25 @@ func TestBackoff(t *testing.T) {
 		}
 	}
 }
+
+func TestBackoffInterval(t *testing.T) {
+	minTime := 100 * time.Millisecond
+	maxTime := 300 * time.Millisecond
+
+	r := &testRequest{
+		service: "test",
+		method:  "test",
+	}
+
+	fn := BackoffInterval(minTime, maxTime)
+	for i := 0; i < 5; i++ {
+		d, err := fn(context.TODO(), r, i)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if d < minTime || d > maxTime {
+			t.Fatalf("Expected %v < %v < %v", minTime, d, maxTime)
+		}
+	}
+}

client/client.go

@@ -5,17 +5,17 @@ import (
 	"context"
 	"time"
 
-	"github.com/unistack-org/micro/v3/codec"
-	"github.com/unistack-org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/metadata"
 )
 
 var (
 	// DefaultClient is the global default client
-	DefaultClient Client = NewClient()
+	DefaultClient = NewClient()
 	// DefaultContentType is the default content-type if not specified
-	DefaultContentType = "application/json"
-	// DefaultBackoff is the default backoff function for retries
-	DefaultBackoff = exponentialBackoff
+	DefaultContentType = ""
+	// DefaultBackoff is the default backoff function for retries (minimum 10 millisecond and maximum 5 second)
+	DefaultBackoff = BackoffInterval(10*time.Millisecond, 5*time.Second)
 	// DefaultRetry is the default check-for-retry function for retries
 	DefaultRetry = RetryNever
 	// DefaultRetries is the default number of times a request is tried
@@ -29,27 +29,23 @@ var (
 )
 
 // Client is the interface used to make requests to services.
-// It supports Request/Response via Transport and Publishing via the Broker.
 // It also supports bidirectional streaming of requests.
 type Client interface {
 	Name() string
 	Init(opts ...Option) error
 	Options() Options
-	NewMessage(topic string, msg interface{}, opts ...MessageOption) Message
 	NewRequest(service string, endpoint string, req interface{}, opts ...RequestOption) Request
 	Call(ctx context.Context, req Request, rsp interface{}, opts ...CallOption) error
 	Stream(ctx context.Context, req Request, opts ...CallOption) (Stream, error)
-	Publish(ctx context.Context, msg Message, opts ...PublishOption) error
-	BatchPublish(ctx context.Context, msg []Message, opts ...PublishOption) error
 	String() string
 }
 
-// Message is the interface for publishing asynchronously
-type Message interface {
-	Topic() string
-	Payload() interface{}
-	ContentType() string
-}
+type (
+	FuncCall   func(ctx context.Context, req Request, rsp interface{}, opts ...CallOption) error
+	HookCall   func(next FuncCall) FuncCall
+	FuncStream func(ctx context.Context, req Request, opts ...CallOption) (Stream, error)
+	HookStream func(next FuncStream) FuncStream
+)
 
 // Request is the interface for a synchronous request used by Call or Stream
 type Request interface {
@@ -73,7 +69,7 @@ type Request interface {
 type Response interface {
 	// Read the response
 	Codec() codec.Codec
-	// read the header
+	// Header data
 	Header() metadata.Metadata
 	// Read the undecoded response
 	Read() ([]byte, error)
@@ -91,10 +87,16 @@ type Stream interface {
 	Send(msg interface{}) error
 	// Recv will decode and read a response
 	Recv(msg interface{}) error
+	// SendMsg will encode and send a request
+	SendMsg(msg interface{}) error
+	// RecvMsg will decode and read a response
+	RecvMsg(msg interface{}) error
 	// Error returns the stream error
 	Error() error
 	// Close closes the stream
 	Close() error
+	// CloseSend closes the send direction of the stream
+	CloseSend() error
 }
 
 // Option used by the Client
@@ -103,11 +105,5 @@ type Option func(*Options)
 // CallOption used by Call or Stream
 type CallOption func(*CallOptions)
 
-// PublishOption used by Publish
-type PublishOption func(*PublishOptions)
-
-// MessageOption used by NewMessage
-type MessageOption func(*MessageOptions)
-
 // RequestOption used by NewRequest
 type RequestOption func(*RequestOptions)

client/context.go

@@ -15,6 +15,15 @@ func FromContext(ctx context.Context) (Client, bool) {
 	return c, ok
 }
 
+// MustContext get client from context
+func MustContext(ctx context.Context) Client {
+	c, ok := FromContext(ctx)
+	if !ok {
+		panic("missing client")
+	}
+	return c
+}
+
 // NewContext put client in context
 func NewContext(ctx context.Context, c Client) context.Context {
 	if ctx == nil {
@@ -23,16 +32,6 @@ func NewContext(ctx context.Context, c Client) context.Context {
 	return context.WithValue(ctx, clientKey{}, c)
 }
 
-// SetPublishOption returns a function to setup a context with given value
-func SetPublishOption(k, v interface{}) PublishOption {
-	return func(o *PublishOptions) {
-		if o.Context == nil {
-			o.Context = context.Background()
-		}
-		o.Context = context.WithValue(o.Context, k, v)
-	}
-}
-
 // SetCallOption returns a function to setup a context with given value
 func SetCallOption(k, v interface{}) CallOption {
 	return func(o *CallOptions) {

client/context_test.go

@@ -0,0 +1,62 @@
+package client
+
+import (
+	"context"
+	"testing"
+)
+
+func TestFromContext(t *testing.T) {
+	ctx := context.WithValue(context.TODO(), clientKey{}, NewClient())
+
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("FromContext not works")
+	}
+}
+
+func TestFromNilContext(t *testing.T) {
+	// nolint: staticcheck
+	c, ok := FromContext(nil)
+	if ok || c != nil {
+		t.Fatal("FromContext not works")
+	}
+}
+
+func TestNewContext(t *testing.T) {
+	ctx := NewContext(context.TODO(), NewClient())
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("NewContext not works")
+	}
+}
+
+func TestNewNilContext(t *testing.T) {
+	// nolint: staticcheck
+	ctx := NewContext(nil, NewClient())
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("NewContext not works")
+	}
+}
+
+func TestSetCallOption(t *testing.T) {
+	type key struct{}
+	o := SetCallOption(key{}, "test")
+	opts := &CallOptions{}
+	o(opts)
+
+	if v, ok := opts.Context.Value(key{}).(string); !ok || v == "" {
+		t.Fatal("SetCallOption not works")
+	}
+}
+
+func TestSetOption(t *testing.T) {
+	type key struct{}
+	o := SetOption(key{}, "test")
+	opts := &Options{}
+	o(opts)
+
+	if v, ok := opts.Context.Value(key{}).(string); !ok || v == "" {
+		t.Fatal("SetOption not works")
+	}
+}

client/lookup.go

@@ -4,15 +4,15 @@ import (
 	"context"
 	"sort"
 
-	"github.com/unistack-org/micro/v3/errors"
-	"github.com/unistack-org/micro/v3/router"
+	"go.unistack.org/micro/v4/errors"
+	"go.unistack.org/micro/v4/router"
 )
 
 // LookupFunc is used to lookup routes for a service
 type LookupFunc func(context.Context, Request, CallOptions) ([]string, error)
 
 // LookupRoute for a request using the router and then choose one using the selector
-func LookupRoute(ctx context.Context, req Request, opts CallOptions) ([]string, error) {
+func LookupRoute(_ context.Context, req Request, opts CallOptions) ([]string, error) {
 	// check to see if an address was provided as a call option
 	if len(opts.Address) > 0 {
 		return opts.Address, nil

client/noop.go

@@ -2,11 +2,17 @@ package client
 
 import (
 	"context"
+	"fmt"
+	"strconv"
+	"time"
 
-	"github.com/unistack-org/micro/v3/broker"
-	"github.com/unistack-org/micro/v3/codec"
-	"github.com/unistack-org/micro/v3/errors"
-	"github.com/unistack-org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/errors"
+	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v4/options"
+	"go.unistack.org/micro/v4/selector"
+	"go.unistack.org/micro/v4/semconv"
+	"go.unistack.org/micro/v4/tracer"
 )
 
 // DefaultCodecs will be used to encode/decode data
@@ -15,13 +21,9 @@ var DefaultCodecs = map[string]codec.Codec{
 }
 
 type noopClient struct {
-	opts Options
-}
-
-type noopMessage struct {
-	topic   string
-	payload interface{}
-	opts    MessageOptions
+	funcCall   FuncCall
+	funcStream FuncStream
+	opts       Options
 }
 
 type noopRequest struct {
@@ -36,16 +38,12 @@ type noopRequest struct {
 
 // NewClient returns new noop client
 func NewClient(opts ...Option) Client {
-	nc := &noopClient{opts: NewOptions(opts...)}
-	// wrap in reverse
+	n := &noopClient{opts: NewOptions(opts...)}
 
-	c := Client(nc)
+	n.funcCall = n.fnCall
+	n.funcStream = n.fnStream
 
-	for i := len(nc.opts.Wrappers); i > 0; i-- {
-		c = nc.opts.Wrappers[i-1](c)
-	}
-
-	return c
+	return n
 }
 
 func (n *noopClient) Name() string {
@@ -97,10 +95,13 @@ func (n *noopResponse) Read() ([]byte, error) {
 	return nil, nil
 }
 
-type noopStream struct{}
+type noopStream struct {
+	err error
+	ctx context.Context
+}
 
 func (n *noopStream) Context() context.Context {
-	return context.Background()
+	return n.ctx
 }
 
 func (n *noopStream) Request() Request {
@@ -119,40 +120,49 @@ func (n *noopStream) Recv(interface{}) error {
 	return nil
 }
 
-func (n *noopStream) Error() error {
+func (n *noopStream) SendMsg(interface{}) error {
 	return nil
 }
 
+func (n *noopStream) RecvMsg(interface{}) error {
+	return nil
+}
+
+func (n *noopStream) Error() error {
+	return n.err
+}
+
 func (n *noopStream) Close() error {
-	return nil
-}
-
-func (n *noopMessage) Topic() string {
-	return n.topic
-}
-
-func (n *noopMessage) Payload() interface{} {
-	return n.payload
-}
-
-func (n *noopMessage) ContentType() string {
-	return n.opts.ContentType
-}
-
-func (n *noopClient) newCodec(contentType string) (codec.Codec, error) {
-	if cf, ok := n.opts.Codecs[contentType]; ok {
-		return cf, nil
+	if sp, ok := tracer.SpanFromContext(n.ctx); ok && sp != nil {
+		if n.err != nil {
+			sp.SetStatus(tracer.SpanStatusError, n.err.Error())
+		}
+		sp.Finish()
 	}
-	if cf, ok := DefaultCodecs[contentType]; ok {
-		return cf, nil
-	}
-	return nil, codec.ErrUnknownContentType
+	return n.err
+}
+
+func (n *noopStream) CloseSend() error {
+	return n.err
 }
 
 func (n *noopClient) Init(opts ...Option) error {
 	for _, o := range opts {
 		o(&n.opts)
 	}
+
+	n.funcCall = n.fnCall
+	n.funcStream = n.fnStream
+
+	n.opts.Hooks.EachPrev(func(hook options.Hook) {
+		switch h := hook.(type) {
+		case HookCall:
+			n.funcCall = h(n.funcCall)
+		case HookStream:
+			n.funcStream = h(n.funcStream)
+		}
+	})
+
 	return nil
 }
 
@@ -165,76 +175,328 @@ func (n *noopClient) String() string {
 }
 
 func (n *noopClient) Call(ctx context.Context, req Request, rsp interface{}, opts ...CallOption) error {
-	return nil
+	ts := time.Now()
+	n.opts.Meter.Counter(semconv.ClientRequestInflight, "endpoint", req.Endpoint()).Inc()
+	var sp tracer.Span
+	ctx, sp = n.opts.Tracer.Start(ctx, "rpc-client",
+		tracer.WithSpanKind(tracer.SpanKindClient),
+		tracer.WithSpanLabels("endpoint", req.Endpoint()),
+	)
+	err := n.funcCall(ctx, req, rsp, opts...)
+	n.opts.Meter.Counter(semconv.ClientRequestInflight, "endpoint", req.Endpoint()).Dec()
+	te := time.Since(ts)
+	n.opts.Meter.Summary(semconv.ClientRequestLatencyMicroseconds, "endpoint", req.Endpoint()).Update(te.Seconds())
+	n.opts.Meter.Histogram(semconv.ClientRequestDurationSeconds, "endpoint", req.Endpoint()).Update(te.Seconds())
+
+	if me := errors.FromError(err); me == nil {
+		sp.Finish()
+		n.opts.Meter.Counter(semconv.ClientRequestTotal, "endpoint", req.Endpoint(), "status", "success", "code", strconv.Itoa(int(200))).Inc()
+	} else {
+		sp.SetStatus(tracer.SpanStatusError, err.Error())
+		n.opts.Meter.Counter(semconv.ClientRequestTotal, "endpoint", req.Endpoint(), "status", "failure", "code", strconv.Itoa(int(me.Code))).Inc()
+	}
+
+	return err
 }
 
-func (n *noopClient) NewRequest(service, endpoint string, req interface{}, opts ...RequestOption) Request {
+func (n *noopClient) fnCall(ctx context.Context, req Request, rsp interface{}, opts ...CallOption) error {
+	// make a copy of call opts
+	callOpts := n.opts.CallOptions
+	for _, opt := range opts {
+		opt(&callOpts)
+	}
+
+	// check if we already have a deadline
+	d, ok := ctx.Deadline()
+	if !ok {
+		var cancel context.CancelFunc
+		// no deadline so we create a new one
+		ctx, cancel = context.WithTimeout(ctx, callOpts.RequestTimeout)
+		defer cancel()
+	} else {
+		// got a deadline so no need to setup context
+		// but we need to set the timeout we pass along
+		opt := WithRequestTimeout(time.Until(d))
+		opt(&callOpts)
+	}
+
+	// should we noop right here?
+	select {
+	case <-ctx.Done():
+		return errors.New("go.micro.client", fmt.Sprintf("%v", ctx.Err()), 408)
+	default:
+	}
+
+	// make copy of call method
+	hcall := func(ctx context.Context, addr string, req Request, rsp interface{}, opts CallOptions) error {
+		return nil
+	}
+
+	// use the router passed as a call option, or fallback to the rpc clients router
+	if callOpts.Router == nil {
+		callOpts.Router = n.opts.Router
+	}
+
+	if callOpts.Selector == nil {
+		callOpts.Selector = n.opts.Selector
+	}
+
+	// inject proxy address
+	// TODO: don't even bother using Lookup/Select in this case
+	if len(n.opts.Proxy) > 0 {
+		callOpts.Address = []string{n.opts.Proxy}
+	}
+
+	var next selector.Next
+
+	// return errors.New("go.micro.client", "request timeout", 408)
+	call := func(i int) error {
+		// call backoff first. Someone may want an initial start delay
+		t, err := callOpts.Backoff(ctx, req, i)
+		if err != nil {
+			return errors.InternalServerError("go.micro.client", "%s", err)
+		}
+
+		// only sleep if greater than 0
+		if t.Seconds() > 0 {
+			time.Sleep(t)
+		}
+
+		if next == nil {
+			var routes []string
+			// lookup the route to send the reques to
+			// TODO apply any filtering here
+			routes, err = n.opts.Lookup(ctx, req, callOpts)
+			if err != nil {
+				return errors.InternalServerError("go.micro.client", "%s", err)
+			}
+
+			// balance the list of nodes
+			next, err = callOpts.Selector.Select(routes)
+			if err != nil {
+				return err
+			}
+		}
+
+		node := next()
+
+		// make the call
+		err = hcall(ctx, node, req, rsp, callOpts)
+		// record the result of the call to inform future routing decisions
+		if verr := n.opts.Selector.Record(node, err); verr != nil {
+			return verr
+		}
+
+		// try and transform the error to a go-micro error
+		if verr, ok := err.(*errors.Error); ok {
+			return verr
+		}
+
+		return err
+	}
+
+	ch := make(chan error, callOpts.Retries)
+	var gerr error
+
+	for i := 0; i <= callOpts.Retries; i++ {
+		go func() {
+			ch <- call(i)
+		}()
+
+		select {
+		case <-ctx.Done():
+			return errors.New("go.micro.client", fmt.Sprintf("%v", ctx.Err()), 408)
+		case err := <-ch:
+			// if the call succeeded lets bail early
+			if err == nil {
+				return nil
+			}
+
+			retry, rerr := callOpts.Retry(ctx, req, i, err)
+			if rerr != nil {
+				return rerr
+			}
+
+			if !retry {
+				return err
+			}
+
+			gerr = err
+		}
+	}
+
+	return gerr
+}
+
+func (n *noopClient) NewRequest(service, endpoint string, _ interface{}, _ ...RequestOption) Request {
 	return &noopRequest{service: service, endpoint: endpoint}
 }
 
-func (n *noopClient) NewMessage(topic string, msg interface{}, opts ...MessageOption) Message {
-	options := NewMessageOptions(append([]MessageOption{MessageContentType(n.opts.ContentType)}, opts...)...)
-	return &noopMessage{topic: topic, payload: msg, opts: options}
-}
-
 func (n *noopClient) Stream(ctx context.Context, req Request, opts ...CallOption) (Stream, error) {
-	return &noopStream{}, nil
-}
+	ts := time.Now()
+	n.opts.Meter.Counter(semconv.ClientRequestInflight, "endpoint", req.Endpoint()).Inc()
+	var sp tracer.Span
+	ctx, sp = n.opts.Tracer.Start(ctx, "rpc-client",
+		tracer.WithSpanKind(tracer.SpanKindClient),
+		tracer.WithSpanLabels("endpoint", req.Endpoint()),
+	)
+	stream, err := n.funcStream(ctx, req, opts...)
+	n.opts.Meter.Counter(semconv.ClientRequestInflight, "endpoint", req.Endpoint()).Dec()
+	te := time.Since(ts)
+	n.opts.Meter.Summary(semconv.ClientRequestLatencyMicroseconds, "endpoint", req.Endpoint()).Update(te.Seconds())
+	n.opts.Meter.Histogram(semconv.ClientRequestDurationSeconds, "endpoint", req.Endpoint()).Update(te.Seconds())
 
-func (n *noopClient) BatchPublish(ctx context.Context, ps []Message, opts ...PublishOption) error {
-	return n.publish(ctx, ps, opts...)
-}
-
-func (n *noopClient) Publish(ctx context.Context, p Message, opts ...PublishOption) error {
-	return n.publish(ctx, []Message{p}, opts...)
-}
-
-func (n *noopClient) publish(ctx context.Context, ps []Message, opts ...PublishOption) error {
-	options := NewPublishOptions(opts...)
-
-	msgs := make([]*broker.Message, 0, len(ps))
-
-	for _, p := range ps {
-		md, ok := metadata.FromOutgoingContext(ctx)
-		if !ok {
-			md = metadata.New(0)
-		}
-		md[metadata.HeaderContentType] = p.ContentType()
-
-		topic := p.Topic()
-
-		// get the exchange
-		if len(options.Exchange) > 0 {
-			topic = options.Exchange
-		}
-
-		md[metadata.HeaderTopic] = topic
-
-		var body []byte
-
-		// passed in raw data
-		if d, ok := p.Payload().(*codec.Frame); ok {
-			body = d.Data
-		} else {
-			// use codec for payload
-			cf, err := n.newCodec(p.ContentType())
-			if err != nil {
-				return errors.InternalServerError("go.micro.client", err.Error())
-			}
-
-			// set the body
-			b, err := cf.Marshal(p.Payload())
-			if err != nil {
-				return errors.InternalServerError("go.micro.client", err.Error())
-			}
-			body = b
-		}
-
-		msgs = append(msgs, &broker.Message{Header: md, Body: body})
+	if me := errors.FromError(err); me == nil {
+		sp.Finish()
+		n.opts.Meter.Counter(semconv.ClientRequestTotal, "endpoint", req.Endpoint(), "status", "success", "code", strconv.Itoa(int(200))).Inc()
+	} else {
+		sp.SetStatus(tracer.SpanStatusError, err.Error())
+		n.opts.Meter.Counter(semconv.ClientRequestTotal, "endpoint", req.Endpoint(), "status", "failure", "code", strconv.Itoa(int(me.Code))).Inc()
 	}
 
-	return n.opts.Broker.BatchPublish(ctx, msgs,
-		broker.PublishContext(options.Context),
-		broker.PublishBodyOnly(options.BodyOnly),
-	)
+	return stream, err
+}
+
+func (n *noopClient) fnStream(ctx context.Context, req Request, opts ...CallOption) (Stream, error) {
+	var err error
+
+	// make a copy of call opts
+	callOpts := n.opts.CallOptions
+	for _, o := range opts {
+		o(&callOpts)
+	}
+
+	// check if we already have a deadline
+	d, ok := ctx.Deadline()
+	if !ok && callOpts.StreamTimeout > time.Duration(0) {
+		var cancel context.CancelFunc
+		// no deadline so we create a new one
+		ctx, cancel = context.WithTimeout(ctx, callOpts.StreamTimeout)
+		defer cancel()
+	} else {
+		// got a deadline so no need to setup context
+		// but we need to set the timeout we pass along
+		o := WithStreamTimeout(time.Until(d))
+		o(&callOpts)
+	}
+
+	// should we noop right here?
+	select {
+	case <-ctx.Done():
+		return nil, errors.New("go.micro.client", fmt.Sprintf("%v", ctx.Err()), 408)
+	default:
+	}
+
+	/*
+		// make copy of call method
+		hstream := h.stream
+		// wrap the call in reverse
+		for i := len(callOpts.CallWrappers); i > 0; i-- {
+			hstream = callOpts.CallWrappers[i-1](hstream)
+		}
+	*/
+
+	// use the router passed as a call option, or fallback to the rpc clients router
+	if callOpts.Router == nil {
+		callOpts.Router = n.opts.Router
+	}
+
+	if callOpts.Selector == nil {
+		callOpts.Selector = n.opts.Selector
+	}
+
+	// inject proxy address
+	// TODO: don't even bother using Lookup/Select in this case
+	if len(n.opts.Proxy) > 0 {
+		callOpts.Address = []string{n.opts.Proxy}
+	}
+
+	var next selector.Next
+
+	call := func(i int) (Stream, error) {
+		// call backoff first. Someone may want an initial start delay
+		t, cerr := callOpts.Backoff(ctx, req, i)
+		if cerr != nil {
+			return nil, errors.InternalServerError("go.micro.client", "%s", cerr)
+		}
+
+		// only sleep if greater than 0
+		if t.Seconds() > 0 {
+			time.Sleep(t)
+		}
+
+		if next == nil {
+			var routes []string
+			// lookup the route to send the reques to
+			// TODO apply any filtering here
+			routes, err = n.opts.Lookup(ctx, req, callOpts)
+			if err != nil {
+				return nil, errors.InternalServerError("go.micro.client", "%s", err)
+			}
+
+			// balance the list of nodes
+			next, err = callOpts.Selector.Select(routes)
+			if err != nil {
+				return nil, err
+			}
+		}
+
+		node := next()
+
+		stream, cerr := n.stream(ctx, node, req, callOpts)
+
+		// record the result of the call to inform future routing decisions
+		if verr := n.opts.Selector.Record(node, cerr); verr != nil {
+			return nil, verr
+		}
+
+		// try and transform the error to a go-micro error
+		if verr, ok := cerr.(*errors.Error); ok {
+			return nil, verr
+		}
+
+		return stream, cerr
+	}
+
+	type response struct {
+		stream Stream
+		err    error
+	}
+
+	ch := make(chan response, callOpts.Retries)
+	var grr error
+
+	for i := 0; i <= callOpts.Retries; i++ {
+		go func() {
+			s, cerr := call(i)
+			ch <- response{s, cerr}
+		}()
+
+		select {
+		case <-ctx.Done():
+			return nil, errors.New("go.micro.client", fmt.Sprintf("%v", ctx.Err()), 408)
+		case rsp := <-ch:
+			// if the call succeeded lets bail early
+			if rsp.err == nil {
+				return rsp.stream, nil
+			}
+
+			retry, rerr := callOpts.Retry(ctx, req, i, err)
+			if rerr != nil {
+				return nil, rerr
+			}
+
+			if !retry {
+				return nil, rsp.err
+			}
+
+			grr = rsp.err
+		}
+	}
+
+	return nil, grr
+}
+
+func (n *noopClient) stream(ctx context.Context, _ string, _ Request, _ CallOptions) (Stream, error) {
+	return &noopStream{ctx: ctx}, nil
 }

client/options.go

@@ -3,22 +3,34 @@ package client
 import (
 	"context"
 	"crypto/tls"
+	"net"
 	"time"
 
-	"github.com/unistack-org/micro/v3/broker"
-	"github.com/unistack-org/micro/v3/codec"
-	"github.com/unistack-org/micro/v3/logger"
-	"github.com/unistack-org/micro/v3/meter"
-	"github.com/unistack-org/micro/v3/network/transport"
-	"github.com/unistack-org/micro/v3/register"
-	"github.com/unistack-org/micro/v3/router"
-	"github.com/unistack-org/micro/v3/selector"
-	"github.com/unistack-org/micro/v3/selector/random"
-	"github.com/unistack-org/micro/v3/tracer"
+	"go.unistack.org/micro/v4/broker"
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/logger"
+	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v4/meter"
+	"go.unistack.org/micro/v4/options"
+	"go.unistack.org/micro/v4/register"
+	"go.unistack.org/micro/v4/router"
+	"go.unistack.org/micro/v4/selector"
+	"go.unistack.org/micro/v4/selector/random"
+	"go.unistack.org/micro/v4/tracer"
 )
 
 // Options holds client options
 type Options struct {
+	// Codecs map
+	Codecs map[string]codec.Codec
+
+	// Proxy is used for proxy requests
+	Proxy string
+	// ContentType is used to select codec
+	ContentType string
+	// Name is the client name
+	Name string
+
 	// Selector used to select needed address
 	Selector selector.Selector
 	// Logger used to log messages
@@ -29,28 +41,28 @@ type Options struct {
 	Broker broker.Broker
 	// Meter used for metrics
 	Meter meter.Meter
-	// Router used to get route
-	Router router.Router
-	// Transport used for transfer messages
-	Transport transport.Transport
 	// Context is used for external options
 	Context context.Context
-	// Lookup func used to get destination addr
-	Lookup LookupFunc
-	// Codecs map
-	Codecs map[string]codec.Codec
+	// Router used to get route
+	Router router.Router
+
 	// TLSConfig specifies tls.Config for secure connection
 	TLSConfig *tls.Config
-	// Proxy is used for proxy requests
-	Proxy string
-	// ContentType is used to select codec
-	ContentType string
-	// Name is the client name
-	Name string
+
+	// Lookup func used to get destination addr
+	Lookup LookupFunc
+	// ContextDialer used to connect
+	ContextDialer func(context.Context, string) (net.Conn, error)
+
 	// Wrappers contains wrappers
 	Wrappers []Wrapper
+	// Hooks can be run before broker Publish/BatchPublish and
+	// Subscribe/BatchSubscribe methods
+	Hooks options.Hooks
+
 	// CallOptions contains default CallOptions
 	CallOptions CallOptions
+
 	// PoolSize connection pool size
 	PoolSize int
 	// PoolTTL connection pool ttl
@@ -68,36 +80,54 @@ func NewCallOptions(opts ...CallOption) CallOptions {
 
 // CallOptions holds client call options
 type CallOptions struct {
-	// Router used for route
-	Router router.Router
-	// Selector selects addr
-	Selector selector.Selector
-	// Context used for deadline
-	Context context.Context
-	// Retry func used for retries
-	Retry RetryFunc
-	// Backoff func used for backoff when retry
-	Backoff BackoffFunc
+	// RequestMetadata holds additional metadata for call
+	RequestMetadata metadata.Metadata
+
 	// Network name
 	Network string
 	// Content-Type
 	ContentType string
-	// CallWrappers call wrappers
-	CallWrappers []CallWrapper
-	// SelectOptions selector options
-	SelectOptions []selector.SelectOption
+	// AuthToken string
+	AuthToken string
+
+	// Selector selects addr
+	Selector selector.Selector
+	// Context used for deadline
+	Context context.Context
+	// Router used for route
+	Router router.Router
+	// Retry func used for retries
+
+	// ResponseMetadata holds additional metadata from call
+	ResponseMetadata *metadata.Metadata
+
+	Retry RetryFunc
+	// Backoff func used for backoff when retry
+	Backoff BackoffFunc
+	// ContextDialer used to connect
+	ContextDialer func(context.Context, string) (net.Conn, error)
+
 	// Address specifies static addr list
 	Address []string
-	// Retries specifies retries num
-	Retries int
+	// SelectOptions selector options
+	SelectOptions []selector.SelectOption
+
 	// StreamTimeout stream timeout
 	StreamTimeout time.Duration
 	// RequestTimeout request timeout
 	RequestTimeout time.Duration
+
 	// DialTimeout dial timeout
 	DialTimeout time.Duration
-	// AuthToken string
-	AuthToken string
+	// Retries specifies retries num
+	Retries int
+}
+
+// ContextDialer pass ContextDialer to client
+func ContextDialer(fn func(context.Context, string) (net.Conn, error)) Option {
+	return func(o *Options) {
+		o.ContextDialer = fn
+	}
 }
 
 // Context pass context to client
@@ -107,40 +137,6 @@ func Context(ctx context.Context) Option {
 	}
 }
 
-// NewPublishOptions create new PublishOptions struct from option
-func NewPublishOptions(opts ...PublishOption) PublishOptions {
-	options := PublishOptions{}
-	for _, o := range opts {
-		o(&options)
-	}
-	return options
-}
-
-// PublishOptions holds publish options
-type PublishOptions struct {
-	// BodyOnly will publish only message body
-	BodyOnly bool
-	// Context used for external options
-	Context context.Context
-	// Exchange topic exchange name
-	Exchange string
-}
-
-// NewMessageOptions creates message options struct
-func NewMessageOptions(opts ...MessageOption) MessageOptions {
-	options := MessageOptions{}
-	for _, o := range opts {
-		o(&options)
-	}
-	return options
-}
-
-// MessageOptions holds client message options
-type MessageOptions struct {
-	// ContentType specify content-type of message
-	ContentType string
-}
-
 // NewRequestOptions creates new RequestOptions struct
 func NewRequestOptions(opts ...RequestOption) RequestOptions {
 	options := RequestOptions{}
@@ -165,25 +161,23 @@ func NewOptions(opts ...Option) Options {
 	options := Options{
 		Context:     context.Background(),
 		ContentType: DefaultContentType,
-		Codecs:      make(map[string]codec.Codec),
+		Codecs:      DefaultCodecs,
 		CallOptions: CallOptions{
 			Context:        context.Background(),
 			Backoff:        DefaultBackoff,
 			Retry:          DefaultRetry,
 			Retries:        DefaultRetries,
 			RequestTimeout: DefaultRequestTimeout,
-			DialTimeout:    transport.DefaultDialTimeout,
 		},
-		Lookup:    LookupRoute,
-		PoolSize:  DefaultPoolSize,
-		PoolTTL:   DefaultPoolTTL,
-		Selector:  random.NewSelector(),
-		Logger:    logger.DefaultLogger,
-		Broker:    broker.DefaultBroker,
-		Meter:     meter.DefaultMeter,
-		Tracer:    tracer.DefaultTracer,
-		Router:    router.DefaultRouter,
-		Transport: transport.DefaultTransport,
+		Lookup:   LookupRoute,
+		PoolSize: DefaultPoolSize,
+		PoolTTL:  DefaultPoolTTL,
+		Selector: random.NewSelector(),
+		Logger:   logger.DefaultLogger,
+		Broker:   broker.DefaultBroker,
+		Meter:    meter.DefaultMeter,
+		Tracer:   tracer.DefaultTracer,
+		Router:   router.DefaultRouter,
 	}
 
 	for _, o := range opts {
@@ -256,18 +250,11 @@ func PoolTTL(d time.Duration) Option {
 	}
 }
 
-// Transport to use for communication e.g http, rabbitmq, etc
-func Transport(t transport.Transport) Option {
-	return func(o *Options) {
-		o.Transport = t
-	}
-}
-
 // Register sets the routers register
 func Register(r register.Register) Option {
 	return func(o *Options) {
 		if o.Router != nil {
-			o.Router.Init(router.Register(r))
+			_ = o.Router.Init(router.Register(r))
 		}
 	}
 }
@@ -286,20 +273,6 @@ func Selector(s selector.Selector) Option {
 	}
 }
 
-// Wrap adds a wrapper to the list of options passed into the client
-func Wrap(w Wrapper) Option {
-	return func(o *Options) {
-		o.Wrappers = append(o.Wrappers, w)
-	}
-}
-
-// WrapCall adds a wrapper to the list of CallFunc wrappers
-func WrapCall(cw ...CallWrapper) Option {
-	return func(o *Options) {
-		o.CallOptions.CallWrappers = append(o.CallOptions.CallWrappers, cw...)
-	}
-}
-
 // Backoff is used to set the backoff function used when retrying Calls
 func Backoff(fn BackoffFunc) Option {
 	return func(o *Options) {
@@ -326,14 +299,6 @@ func TLSConfig(t *tls.Config) Option {
 	return func(o *Options) {
 		// set the internal tls
 		o.TLSConfig = t
-
-		// set the default transport if one is not
-		// already set. Required for Init call below.
-
-		// set the transport tls
-		o.Transport.Init(
-			transport.TLSConfig(t),
-		)
 	}
 }
 
@@ -372,40 +337,10 @@ func DialTimeout(d time.Duration) Option {
 	}
 }
 
-// WithExchange sets the exchange to route a message through
-// Deprecated
-func WithExchange(e string) PublishOption {
-	return func(o *PublishOptions) {
-		o.Exchange = e
-	}
-}
-
-// PublishExchange sets the exchange to route a message through
-func PublishExchange(e string) PublishOption {
-	return func(o *PublishOptions) {
-		o.Exchange = e
-	}
-}
-
-// WithBodyOnly publish only message body
-// DERECATED
-func WithBodyOnly(b bool) PublishOption {
-	return func(o *PublishOptions) {
-		o.BodyOnly = b
-	}
-}
-
-// PublishBodyOnly publish only message body
-func PublishBodyOnly(b bool) PublishOption {
-	return func(o *PublishOptions) {
-		o.BodyOnly = b
-	}
-}
-
-// PublishContext sets the context in publish options
-func PublishContext(ctx context.Context) PublishOption {
-	return func(o *PublishOptions) {
-		o.Context = ctx
+// WithContextDialer pass ContextDialer to client call
+func WithContextDialer(fn func(context.Context, string) (net.Conn, error)) CallOption {
+	return func(o *CallOptions) {
+		o.ContextDialer = fn
 	}
 }
 
@@ -423,13 +358,6 @@ func WithAddress(a ...string) CallOption {
 	}
 }
 
-// WithCallWrapper is a CallOption which adds to the existing CallFunc wrappers
-func WithCallWrapper(cw ...CallWrapper) CallOption {
-	return func(o *CallOptions) {
-		o.CallWrappers = append(o.CallWrappers, cw...)
-	}
-}
-
 // WithBackoff is a CallOption which overrides that which
 // set in Options.CallOptions
 func WithBackoff(fn BackoffFunc) CallOption {
@@ -454,6 +382,20 @@ func WithRetries(i int) CallOption {
 	}
 }
 
+// WithResponseMetadata is a CallOption which adds metadata.Metadata to Options.CallOptions
+func WithResponseMetadata(md *metadata.Metadata) CallOption {
+	return func(o *CallOptions) {
+		o.ResponseMetadata = md
+	}
+}
+
+// WithRequestMetadata is a CallOption which adds metadata.Metadata to Options.CallOptions
+func WithRequestMetadata(md metadata.Metadata) CallOption {
+	return func(o *CallOptions) {
+		o.RequestMetadata = md
+	}
+}
+
 // WithRequestTimeout is a CallOption which overrides that which
 // set in Options.CallOptions
 func WithRequestTimeout(d time.Duration) CallOption {
@@ -485,13 +427,6 @@ func WithAuthToken(t string) CallOption {
 	}
 }
 
-// WithNetwork is a CallOption which sets the network attribute
-func WithNetwork(n string) CallOption {
-	return func(o *CallOptions) {
-		o.Network = n
-	}
-}
-
 // WithRouter sets the router to use for this call
 func WithRouter(r router.Router) CallOption {
 	return func(o *CallOptions) {
@@ -513,21 +448,6 @@ func WithSelectOptions(sops ...selector.SelectOption) CallOption {
 	}
 }
 
-// WithMessageContentType sets the message content type
-// Deprecated
-func WithMessageContentType(ct string) MessageOption {
-	return func(o *MessageOptions) {
-		o.ContentType = ct
-	}
-}
-
-// MessageContentType sets the message content type
-func MessageContentType(ct string) MessageOption {
-	return func(o *MessageOptions) {
-		o.ContentType = ct
-	}
-}
-
 // StreamingRequest specifies that request is streaming
 func StreamingRequest(b bool) RequestOption {
 	return func(o *RequestOptions) {
@@ -541,3 +461,10 @@ func RequestContentType(ct string) RequestOption {
 		o.ContentType = ct
 	}
 }
+
+// Hooks sets hook runs before action
+func Hooks(h ...options.Hook) Option {
+	return func(o *Options) {
+		o.Hooks = append(o.Hooks, h...)
+	}
+}

client/retry.go

@@ -3,7 +3,7 @@ package client
 import (
 	"context"
 
-	"github.com/unistack-org/micro/v3/errors"
+	"go.unistack.org/micro/v4/errors"
 )
 
 // RetryFunc that returning either false or a non-nil error will result in the call not being retried
@@ -19,18 +19,32 @@ func RetryNever(ctx context.Context, req Request, retryCount int, err error) (bo
 	return false, nil
 }
 
-// RetryOnError retries a request on a 500 or timeout error
-func RetryOnError(ctx context.Context, req Request, retryCount int, err error) (bool, error) {
+// RetryOnError retries a request on a 500 or 408 (timeout) error
+func RetryOnError(_ context.Context, _ Request, _ int, err error) (bool, error) {
 	if err == nil {
 		return false, nil
 	}
-
 	me := errors.FromError(err)
 	switch me.Code {
 	// retry on timeout or internal server error
 	case 408, 500:
 		return true, nil
 	}
-
 	return false, nil
 }
+
+// RetryOnErrors retries a request on specified error codes
+func RetryOnErrors(codes ...int32) RetryFunc {
+	return func(_ context.Context, _ Request, _ int, err error) (bool, error) {
+		if err == nil {
+			return false, nil
+		}
+		me := errors.FromError(err)
+		for _, code := range codes {
+			if me.Code == code {
+				return true, nil
+			}
+		}
+		return false, nil
+	}
+}

client/retry_test.go

@@ -0,0 +1,70 @@
+package client
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"go.unistack.org/micro/v4/errors"
+)
+
+func TestRetryAlways(t *testing.T) {
+	tests := []error{
+		nil,
+		errors.InternalServerError("test", "%s", "test"),
+		fmt.Errorf("test"),
+	}
+
+	for _, e := range tests {
+		ok, er := RetryAlways(context.TODO(), nil, 1, e)
+		if !ok || er != nil {
+			t.Fatal("RetryAlways not works properly")
+		}
+	}
+}
+
+func TestRetryNever(t *testing.T) {
+	tests := []error{
+		nil,
+		errors.InternalServerError("test", "%s", "test"),
+		fmt.Errorf("test"),
+	}
+
+	for _, e := range tests {
+		ok, er := RetryNever(context.TODO(), nil, 1, e)
+		if ok || er != nil {
+			t.Fatal("RetryNever not works properly")
+		}
+	}
+}
+
+func TestRetryOnError(t *testing.T) {
+	tests := []error{
+		fmt.Errorf("test"),
+		errors.NotFound("test", "%s", "test"),
+		errors.Timeout("test", "%s", "test"),
+	}
+
+	for i, e := range tests {
+		ok, er := RetryOnError(context.TODO(), nil, 1, e)
+		if i == 2 && (!ok || er != nil) {
+			t.Fatal("RetryOnError not works properly")
+		}
+	}
+}
+
+func TestRetryOnErrors(t *testing.T) {
+	tests := []error{
+		fmt.Errorf("test"),
+		errors.NotFound("test", "%s", "test"),
+		errors.Timeout("test", "%s", "test"),
+	}
+
+	fn := RetryOnErrors(404)
+	for i, e := range tests {
+		ok, er := fn(context.TODO(), nil, 1, e)
+		if i == 1 && (!ok || er != nil) {
+			t.Fatal("RetryOnErrors not works properly")
+		}
+	}
+}

client/test_request.go

@@ -1,7 +1,7 @@
 package client
 
 import (
-	"github.com/unistack-org/micro/v3/codec"
+	"go.unistack.org/micro/v4/codec"
 )
 
 type testRequest struct {

cluster/cluster.go

@@ -0,0 +1,47 @@
+package cluster
+
+import (
+	"context"
+
+	"go.unistack.org/micro/v4/metadata"
+)
+
+// Message sent to member in cluster
+type Message interface {
+	// Header returns message headers
+	Header() metadata.Metadata
+	// Body returns broker message may be []byte slice or some go struct or interface
+	Body() interface{}
+}
+
+type Node interface {
+	// Name returns node name
+	Name() string
+	// Address returns node address
+	Address() string
+	// Metadata returns node metadata
+	Metadata() metadata.Metadata
+}
+
+// Cluster interface used for cluster communication across nodes
+type Cluster interface {
+	// Join is used to take an existing members and performing state sync
+	Join(ctx context.Context, addr ...string) error
+	// Leave broadcast a leave message and stop listeners
+	Leave(ctx context.Context) error
+	// Ping is used to probe live status of the node
+	Ping(ctx context.Context, node Node, payload []byte) error
+	// Members returns the cluster members
+	Members() ([]Node, error)
+	// Broadcast send message for all members in cluster, if filter is not nil, nodes may be filtered
+	// by key/value pairs
+	Broadcast(ctx context.Context, msg Message, filter ...string) error
+	// Unicast send message to single member in cluster
+	Unicast(ctx context.Context, node Node, msg Message) error
+	// Live returns cluster liveness
+	Live() bool
+	// Ready returns cluster readiness
+	Ready() bool
+	// Health returns cluster health
+	Health() bool
+}

codec/codec.go

@@ -3,17 +3,8 @@ package codec
 
 import (
 	"errors"
-	"io"
 
-	"github.com/unistack-org/micro/v3/metadata"
-)
-
-// Message types
-const (
-	Error MessageType = iota
-	Request
-	Response
-	Event
+	"gopkg.in/yaml.v3"
 )
 
 var (
@@ -24,46 +15,63 @@ var (
 )
 
 var (
-	// DefaultMaxMsgSize specifies how much data codec can handle
-	DefaultMaxMsgSize int = 1024 * 1024 * 4 // 4Mb
 	// DefaultCodec is the global default codec
-	DefaultCodec Codec = NewCodec()
+	DefaultCodec = NewCodec()
 	// DefaultTagName specifies struct tag name to control codec Marshal/Unmarshal
 	DefaultTagName = "codec"
 )
 
-// MessageType specifies message type for codec
-type MessageType int
-
-// Codec encodes/decodes various types of messages used within micro.
-// ReadHeader and ReadBody are called in pairs to read requests/responses
-// from the connection. Close is called when finished with the
-// connection. ReadBody may be called with a nil argument to force the
-// body to be read and discarded.
+// Codec encodes/decodes various types of messages.
 type Codec interface {
-	ReadHeader(io.Reader, *Message, MessageType) error
-	ReadBody(io.Reader, interface{}) error
-	Write(io.Writer, *Message, interface{}) error
-	Marshal(interface{}) ([]byte, error)
-	Unmarshal([]byte, interface{}) error
+	Marshal(v interface{}, opts ...Option) ([]byte, error)
+	Unmarshal(b []byte, v interface{}, opts ...Option) error
 	String() string
 }
 
-// Message represents detailed information about
-// the communication, likely followed by the body.
-// In the case of an error, body may be nil.
-type Message struct {
-	Header   metadata.Metadata
-	Target   string
-	Method   string
-	Endpoint string
-	Error    string
-	Id       string
-	Body     []byte
-	Type     MessageType
+type CodecV2 interface {
+	Marshal(buf []byte, v interface{}, opts ...Option) ([]byte, error)
+	Unmarshal(buf []byte, v interface{}, opts ...Option) error
+	String() string
 }
 
-// NewMessage creates new codec message
-func NewMessage(t MessageType) *Message {
-	return &Message{Type: t, Header: metadata.New(0)}
+// RawMessage is a raw encoded JSON value.
+// It implements Marshaler and Unmarshaler and can be used to delay decoding or precompute a encoding.
+type RawMessage []byte
+
+// MarshalJSON returns m as the JSON encoding of m.
+func (m *RawMessage) MarshalJSON() ([]byte, error) {
+	if m == nil {
+		return []byte("null"), nil
+	} else if len(*m) == 0 {
+		return []byte("null"), nil
+	}
+	return *m, nil
+}
+
+// UnmarshalJSON sets *m to a copy of data.
+func (m *RawMessage) UnmarshalJSON(data []byte) error {
+	if m == nil {
+		return errors.New("RawMessage UnmarshalJSON on nil pointer")
+	}
+	*m = append((*m)[0:0], data...)
+	return nil
+}
+
+// MarshalYAML returns m as the JSON encoding of m.
+func (m *RawMessage) MarshalYAML() ([]byte, error) {
+	if m == nil {
+		return []byte("null"), nil
+	} else if len(*m) == 0 {
+		return []byte("null"), nil
+	}
+	return *m, nil
+}
+
+// UnmarshalYAML sets *m to a copy of data.
+func (m *RawMessage) UnmarshalYAML(n *yaml.Node) error {
+	if m == nil {
+		return errors.New("RawMessage UnmarshalYAML on nil pointer")
+	}
+	*m = append((*m)[0:0], []byte(n.Value)...)
+	return nil
 }

codec/context.go

@@ -0,0 +1,43 @@
+package codec
+
+import (
+	"context"
+)
+
+type codecKey struct{}
+
+// FromContext returns codec from context
+func FromContext(ctx context.Context) (Codec, bool) {
+	if ctx == nil {
+		return nil, false
+	}
+	c, ok := ctx.Value(codecKey{}).(Codec)
+	return c, ok
+}
+
+// MustContext returns codec from context
+func MustContext(ctx context.Context) Codec {
+	c, ok := FromContext(ctx)
+	if !ok {
+		panic("missing codec")
+	}
+	return c
+}
+
+// NewContext put codec in context
+func NewContext(ctx context.Context, c Codec) context.Context {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	return context.WithValue(ctx, codecKey{}, c)
+}
+
+// SetOption returns a function to setup a context with given value
+func SetOption(k, v interface{}) Option {
+	return func(o *Options) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, k, v)
+	}
+}

codec/context_test.go

@@ -0,0 +1,35 @@
+package codec
+
+import (
+	"context"
+	"testing"
+)
+
+func TestFromContext(t *testing.T) {
+	ctx := context.WithValue(context.TODO(), codecKey{}, NewCodec())
+
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("FromContext not works")
+	}
+}
+
+func TestNewContext(t *testing.T) {
+	ctx := NewContext(context.TODO(), NewCodec())
+
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("NewContext not works")
+	}
+}
+
+func TestSetOption(t *testing.T) {
+	type key struct{}
+	o := SetOption(key{}, "test")
+	opts := &Options{}
+	o(opts)
+
+	if v, ok := opts.Context.Value(key{}).(string); !ok || v == "" {
+		t.Fatal("SetOption not works")
+	}
+}

codec/frame.go

@@ -1,6 +1,58 @@
 package codec
 
+import "gopkg.in/yaml.v3"
+
 // Frame gives us the ability to define raw data to send over the pipes
 type Frame struct {
 	Data []byte
 }
+
+// NewFrame returns new frame with data
+func NewFrame(data []byte) *Frame {
+	return &Frame{Data: data}
+}
+
+// MarshalJSON returns frame data
+func (m *Frame) MarshalJSON() ([]byte, error) {
+	return m.Marshal()
+}
+
+// UnmarshalJSON set frame data
+func (m *Frame) UnmarshalJSON(data []byte) error {
+	return m.Unmarshal(data)
+}
+
+// MarshalYAML returns frame data
+func (m *Frame) MarshalYAML() ([]byte, error) {
+	return m.Marshal()
+}
+
+// UnmarshalYAML set frame data
+func (m *Frame) UnmarshalYAML(n *yaml.Node) error {
+	m.Data = []byte(n.Value)
+	return nil
+}
+
+// ProtoMessage noop func
+func (m *Frame) ProtoMessage() {}
+
+// Reset resets frame
+func (m *Frame) Reset() {
+	*m = Frame{}
+}
+
+// String returns frame as string
+func (m *Frame) String() string {
+	return string(m.Data)
+}
+
+// Marshal returns frame data
+func (m *Frame) Marshal() ([]byte, error) {
+	return m.Data, nil
+}
+
+// Unmarshal set frame data
+func (m *Frame) Unmarshal(data []byte) error {
+	m.Data = data
+	return nil
+}

codec/frame.proto

@@ -17,7 +17,7 @@ syntax = "proto3";
 package micro.codec;
 
 option cc_enable_arenas = true;
-option go_package = "github.com/unistack-org/micro/v3/codec;codec";
+option go_package = "go.unistack.org/micro/v4/codec;codec";
 option java_multiple_files = true;
 option java_outer_classname = "MicroCodec";
 option java_package = "micro.codec";

codec/noop.go

@@ -2,66 +2,12 @@ package codec
 
 import (
 	"encoding/json"
-	"io"
+
+	codecpb "go.unistack.org/micro-proto/v4/codec"
 )
 
-type noopCodec struct{}
-
-func (c *noopCodec) ReadHeader(conn io.Reader, m *Message, t MessageType) error {
-	return nil
-}
-
-func (c *noopCodec) ReadBody(conn io.Reader, b interface{}) error {
-	// read bytes
-	buf, err := io.ReadAll(conn)
-	if err != nil {
-		return err
-	}
-
-	if b == nil {
-		return nil
-	}
-
-	switch v := b.(type) {
-	case *string:
-		*v = string(buf)
-	case *[]byte:
-		*v = buf
-	case *Frame:
-		v.Data = buf
-	default:
-		return json.Unmarshal(buf, v)
-	}
-
-	return nil
-}
-
-func (c *noopCodec) Write(conn io.Writer, m *Message, b interface{}) error {
-	if b == nil {
-		return nil
-	}
-
-	var v []byte
-	switch vb := b.(type) {
-	case *Frame:
-		v = vb.Data
-	case string:
-		v = []byte(vb)
-	case *string:
-		v = []byte(*vb)
-	case *[]byte:
-		v = *vb
-	case []byte:
-		v = vb
-	default:
-		var err error
-		v, err = json.Marshal(vb)
-		if err != nil {
-			return err
-		}
-	}
-	_, err := conn.Write(v)
-	return err
+type noopCodec struct {
+	opts Options
 }
 
 func (c *noopCodec) String() string {
@@ -69,11 +15,11 @@ func (c *noopCodec) String() string {
 }
 
 // NewCodec returns new noop codec
-func NewCodec() Codec {
-	return &noopCodec{}
+func NewCodec(opts ...Option) Codec {
+	return &noopCodec{opts: NewOptions(opts...)}
 }
 
-func (c *noopCodec) Marshal(v interface{}) ([]byte, error) {
+func (c *noopCodec) Marshal(v interface{}, opts ...Option) ([]byte, error) {
 	if v == nil {
 		return nil, nil
 	}
@@ -89,14 +35,14 @@ func (c *noopCodec) Marshal(v interface{}) ([]byte, error) {
 		return ve, nil
 	case *Frame:
 		return ve.Data, nil
-	case *Message:
-		return ve.Body, nil
+	case *codecpb.Frame:
+		return ve.Data, nil
 	}
 
 	return json.Marshal(v)
 }
 
-func (c *noopCodec) Unmarshal(d []byte, v interface{}) error {
+func (c *noopCodec) Unmarshal(d []byte, v interface{}, opts ...Option) error {
 	if v == nil {
 		return nil
 	}
@@ -104,14 +50,17 @@ func (c *noopCodec) Unmarshal(d []byte, v interface{}) error {
 	case *string:
 		*ve = string(d)
 		return nil
+	case []byte:
+		copy(ve, d)
+		return nil
 	case *[]byte:
 		*ve = d
 		return nil
 	case *Frame:
 		ve.Data = d
 		return nil
-	case *Message:
-		ve.Body = d
+	case *codecpb.Frame:
+		ve.Data = d
 		return nil
 	}
 

codec/noop_test.go

@@ -5,7 +5,7 @@ import (
 	"testing"
 )
 
-func TestNoopBytes(t *testing.T) {
+func TestNoopBytesPtr(t *testing.T) {
 	req := []byte("test req")
 	rsp := make([]byte, len(req))
 
@@ -19,6 +19,20 @@ func TestNoopBytes(t *testing.T) {
 	}
 }
 
+func TestNoopBytes(t *testing.T) {
+	req := []byte("test req")
+	var rsp []byte
+
+	nc := NewCodec()
+	if err := nc.Unmarshal(req, &rsp); err != nil {
+		t.Fatal(err)
+	}
+
+	if !bytes.Equal(req, rsp) {
+		t.Fatalf("req not eq rsp: %s != %s", req, rsp)
+	}
+}
+
 func TestNoopString(t *testing.T) {
 	req := []byte("test req")
 	var rsp string

codec/options.go

@@ -1,9 +1,11 @@
 package codec
 
 import (
-	"github.com/unistack-org/micro/v3/logger"
-	"github.com/unistack-org/micro/v3/meter"
-	"github.com/unistack-org/micro/v3/tracer"
+	"context"
+
+	"go.unistack.org/micro/v4/logger"
+	"go.unistack.org/micro/v4/meter"
+	"go.unistack.org/micro/v4/tracer"
 )
 
 // Option func
@@ -17,14 +19,25 @@ type Options struct {
 	Logger logger.Logger
 	// Tracer used for tracing
 	Tracer tracer.Tracer
-	// MaxMsgSize specifies max messages size that reads by codec
-	MaxMsgSize int
+	// Context stores additional codec options
+	Context context.Context
+	// TagName specifies tag name in struct to control codec
+	TagName string
+	// Flatten specifies that struct must be analyzed for flatten tag
+	Flatten bool
 }
 
-// MaxMsgSize sets the max message size
-func MaxMsgSize(n int) Option {
+// TagName sets the codec tag name in struct
+func TagName(n string) Option {
 	return func(o *Options) {
-		o.MaxMsgSize = n
+		o.TagName = n
+	}
+}
+
+// Flatten enables checking for flatten tag name
+func Flatten(b bool) Option {
+	return func(o *Options) {
+		o.Flatten = b
 	}
 }
 
@@ -52,10 +65,12 @@ func Meter(m meter.Meter) Option {
 // NewOptions returns new options
 func NewOptions(opts ...Option) Options {
 	options := Options{
-		Logger:     logger.DefaultLogger,
-		Meter:      meter.DefaultMeter,
-		Tracer:     tracer.DefaultTracer,
-		MaxMsgSize: DefaultMaxMsgSize,
+		Context: context.Background(),
+		Logger:  logger.DefaultLogger,
+		Meter:   meter.DefaultMeter,
+		Tracer:  tracer.DefaultTracer,
+		TagName: DefaultTagName,
+		Flatten: false,
 	}
 
 	for _, o := range opts {

config/config.go

@@ -4,16 +4,21 @@ package config
 import (
 	"context"
 	"errors"
+	"reflect"
 	"time"
 )
 
+type Validator interface {
+	Validate() error
+}
+
 // DefaultConfig default config
-var DefaultConfig Config = NewConfig()
+var DefaultConfig = NewConfig()
 
 // DefaultWatcherMinInterval default min interval for poll changes
 var DefaultWatcherMinInterval = 5 * time.Second
 
-// DefaultWatcherMinInterval default max interval for poll changes
+// DefaultWatcherMaxInterval default max interval for poll changes
 var DefaultWatcherMaxInterval = 9 * time.Second
 
 var (
@@ -23,6 +28,8 @@ var (
 	ErrInvalidStruct = errors.New("invalid struct specified")
 	// ErrWatcherStopped is returned when source watcher has been stopped
 	ErrWatcherStopped = errors.New("watcher stopped")
+	// ErrWatcherNotImplemented returned when config does not implement watch
+	ErrWatcherNotImplemented = errors.New("watcher not implemented")
 )
 
 // Config is an interface abstraction for dynamic configuration
@@ -43,6 +50,13 @@ type Config interface {
 	String() string
 }
 
+type (
+	FuncLoad func(ctx context.Context, opts ...LoadOption) error
+	HookLoad func(next FuncLoad) FuncLoad
+	FuncSave func(ctx context.Context, opts ...SaveOption) error
+	HookSave func(next FuncSave) FuncSave
+)
+
 // Watcher is the config watcher
 type Watcher interface {
 	// Next blocks until update happens or error returned
@@ -64,3 +78,147 @@ func Load(ctx context.Context, cs []Config, opts ...LoadOption) error {
 	}
 	return nil
 }
+
+// Validate runs Validate() error func for each struct field
+func Validate(ctx context.Context, cfg interface{}) error {
+	if cfg == nil {
+		return nil
+	}
+
+	if v, ok := cfg.(Validator); ok {
+		if err := v.Validate(); err != nil {
+			return err
+		}
+	}
+
+	sv := reflect.ValueOf(cfg)
+	if sv.Kind() == reflect.Ptr {
+		sv = sv.Elem()
+	}
+	if sv.Kind() != reflect.Struct {
+		return nil
+	}
+
+	typ := sv.Type()
+	for idx := 0; idx < typ.NumField(); idx++ {
+		fld := typ.Field(idx)
+		val := sv.Field(idx)
+		if !val.IsValid() || len(fld.PkgPath) != 0 {
+			continue
+		}
+
+		if v, ok := val.Interface().(Validator); ok {
+			if err := v.Validate(); err != nil {
+				return err
+			}
+		}
+
+		switch val.Kind() {
+		case reflect.Ptr:
+			if reflect.Indirect(val).Kind() == reflect.Struct {
+				if err := Validate(ctx, val.Interface()); err != nil {
+					return err
+				}
+			}
+		case reflect.Struct:
+			if err := Validate(ctx, val.Interface()); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+var (
+	// DefaultBeforeLoad default func that runs before config Load
+	DefaultBeforeLoad = func(ctx context.Context, c Config) error {
+		for _, fn := range c.Options().BeforeLoad {
+			if fn == nil {
+				return nil
+			}
+			if err := fn(ctx, c); err != nil {
+				c.Options().Logger.Error(ctx, c.String()+" BeforeLoad error", err)
+				if !c.Options().AllowFail {
+					return err
+				}
+			}
+		}
+		return nil
+	}
+	// DefaultAfterLoad default func that runs after config Load
+	DefaultAfterLoad = func(ctx context.Context, c Config) error {
+		for _, fn := range c.Options().AfterLoad {
+			if fn == nil {
+				return nil
+			}
+			if err := fn(ctx, c); err != nil {
+				c.Options().Logger.Error(ctx, c.String()+" AfterLoad error", err)
+				if !c.Options().AllowFail {
+					return err
+				}
+			}
+		}
+		return nil
+	}
+	// DefaultBeforeSave default func that runs befora config Save
+	DefaultBeforeSave = func(ctx context.Context, c Config) error {
+		for _, fn := range c.Options().BeforeSave {
+			if fn == nil {
+				return nil
+			}
+			if err := fn(ctx, c); err != nil {
+				c.Options().Logger.Error(ctx, c.String()+" BeforeSave error", err)
+				if !c.Options().AllowFail {
+					return err
+				}
+			}
+		}
+		return nil
+	}
+	// DefaultAfterSave default func that runs after config Save
+	DefaultAfterSave = func(ctx context.Context, c Config) error {
+		for _, fn := range c.Options().AfterSave {
+			if fn == nil {
+				return nil
+			}
+			if err := fn(ctx, c); err != nil {
+				c.Options().Logger.Error(ctx, c.String()+" AfterSave error", err)
+				if !c.Options().AllowFail {
+					return err
+				}
+			}
+		}
+		return nil
+	}
+	// DefaultBeforeInit default func that runs befora config Init
+	DefaultBeforeInit = func(ctx context.Context, c Config) error {
+		for _, fn := range c.Options().BeforeInit {
+			if fn == nil {
+				return nil
+			}
+			if err := fn(ctx, c); err != nil {
+				c.Options().Logger.Error(ctx, c.String()+" BeforeInit error", err)
+				if !c.Options().AllowFail {
+					return err
+				}
+			}
+		}
+		return nil
+	}
+	// DefaultAfterInit default func that runs after config Init
+	DefaultAfterInit = func(ctx context.Context, c Config) error {
+		for _, fn := range c.Options().AfterSave {
+			if fn == nil {
+				return nil
+			}
+			if err := fn(ctx, c); err != nil {
+				c.Options().Logger.Error(ctx, c.String()+" AfterInit error", err)
+				if !c.Options().AllowFail {
+					return err
+				}
+			}
+		}
+		return nil
+	}
+)

config/context.go

@@ -15,6 +15,15 @@ func FromContext(ctx context.Context) (Config, bool) {
 	return c, ok
 }
 
+// MustContext returns store from context
+func MustContext(ctx context.Context) Config {
+	c, ok := FromContext(ctx)
+	if !ok {
+		panic("missing config")
+	}
+	return c
+}
+
 // NewContext put store in context
 func NewContext(ctx context.Context, c Config) context.Context {
 	if ctx == nil {
@@ -32,3 +41,33 @@ func SetOption(k, v interface{}) Option {
 		o.Context = context.WithValue(o.Context, k, v)
 	}
 }
+
+// SetSaveOption returns a function to setup a context with given value
+func SetSaveOption(k, v interface{}) SaveOption {
+	return func(o *SaveOptions) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, k, v)
+	}
+}
+
+// SetLoadOption returns a function to setup a context with given value
+func SetLoadOption(k, v interface{}) LoadOption {
+	return func(o *LoadOptions) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, k, v)
+	}
+}
+
+// SetWatchOption returns a function to setup a context with given value
+func SetWatchOption(k, v interface{}) WatchOption {
+	return func(o *WatchOptions) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, k, v)
+	}
+}

config/context_test.go

@@ -0,0 +1,86 @@
+package config
+
+import (
+	"context"
+	"testing"
+)
+
+func TestFromNilContext(t *testing.T) {
+	// nolint: staticcheck
+	c, ok := FromContext(nil)
+	if ok || c != nil {
+		t.Fatal("FromContext not works")
+	}
+}
+
+func TestNewNilContext(t *testing.T) {
+	// nolint: staticcheck
+	ctx := NewContext(nil, NewConfig())
+
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("NewContext not works")
+	}
+}
+
+func TestFromContext(t *testing.T) {
+	ctx := context.WithValue(context.TODO(), configKey{}, NewConfig())
+
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("FromContext not works")
+	}
+}
+
+func TestNewContext(t *testing.T) {
+	ctx := NewContext(context.TODO(), NewConfig())
+
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("NewContext not works")
+	}
+}
+
+func TestSetOption(t *testing.T) {
+	type key struct{}
+	o := SetOption(key{}, "test")
+	opts := &Options{}
+	o(opts)
+
+	if v, ok := opts.Context.Value(key{}).(string); !ok || v == "" {
+		t.Fatal("SetOption not works")
+	}
+}
+
+func TestSetSaveOption(t *testing.T) {
+	type key struct{}
+	o := SetSaveOption(key{}, "test")
+	opts := &SaveOptions{}
+	o(opts)
+
+	if v, ok := opts.Context.Value(key{}).(string); !ok || v == "" {
+		t.Fatal("SetSaveOption not works")
+	}
+}
+
+func TestSetLoadOption(t *testing.T) {
+	type key struct{}
+	o := SetLoadOption(key{}, "test")
+	opts := &LoadOptions{}
+	o(opts)
+
+	if v, ok := opts.Context.Value(key{}).(string); !ok || v == "" {
+		t.Fatal("SetLoadOption not works")
+	}
+}
+
+func TestSetWatchOption(t *testing.T) {
+	type key struct{}
+	o := SetWatchOption(key{}, "test")
+	opts := &WatchOptions{}
+	o(opts)
+
+	if v, ok := opts.Context.Value(key{}).(string); !ok || v == "" {
+		t.Fatal("SetWatchOption not works")
+	}
+}

config/default.go

@@ -2,17 +2,23 @@ package config
 
 import (
 	"context"
-	"fmt"
 	"reflect"
 	"strconv"
 	"strings"
+	"time"
 
-	"github.com/imdario/mergo"
-	rutil "github.com/unistack-org/micro/v3/util/reflect"
+	"dario.cat/mergo"
+	"github.com/google/uuid"
+	"go.unistack.org/micro/v4/options"
+	mid "go.unistack.org/micro/v4/util/id"
+	rutil "go.unistack.org/micro/v4/util/reflect"
+	mtime "go.unistack.org/micro/v4/util/time"
 )
 
 type defaultConfig struct {
-	opts Options
+	funcLoad FuncLoad
+	funcSave FuncSave
+	opts     Options
 }
 
 func (c *defaultConfig) Options() Options {
@@ -23,14 +29,43 @@ func (c *defaultConfig) Init(opts ...Option) error {
 	for _, o := range opts {
 		o(&c.opts)
 	}
+
+	if err := DefaultBeforeInit(c.opts.Context, c); err != nil && !c.opts.AllowFail {
+		return err
+	}
+
+	c.funcLoad = c.fnLoad
+	c.funcSave = c.fnSave
+
+	c.opts.Hooks.EachPrev(func(hook options.Hook) {
+		switch h := hook.(type) {
+		case HookLoad:
+			c.funcLoad = h(c.funcLoad)
+		case HookSave:
+			c.funcSave = h(c.funcSave)
+		}
+	})
+
+	if err := DefaultAfterInit(c.opts.Context, c); err != nil && !c.opts.AllowFail {
+		return err
+	}
+
 	return nil
 }
 
 func (c *defaultConfig) Load(ctx context.Context, opts ...LoadOption) error {
-	for _, fn := range c.opts.BeforeLoad {
-		if err := fn(ctx, c); err != nil && !c.opts.AllowFail {
-			return err
-		}
+	return c.funcLoad(ctx, opts...)
+}
+
+func (c *defaultConfig) fnLoad(ctx context.Context, opts ...LoadOption) error {
+	var err error
+
+	if c.opts.SkipLoad != nil && c.opts.SkipLoad(ctx, c) {
+		return nil
+	}
+
+	if err = DefaultBeforeLoad(ctx, c); err != nil && !c.opts.AllowFail {
+		return err
 	}
 
 	options := NewLoadOptions(opts...)
@@ -48,20 +83,25 @@ func (c *defaultConfig) Load(ctx context.Context, opts ...LoadOption) error {
 	}
 
 	src, err := rutil.Zero(dst)
-	if err == nil {
-		if err = fillValues(reflect.ValueOf(src), c.opts.StructTag); err == nil {
-			err = mergo.Merge(dst, src, mopts...)
+	if err != nil {
+		if !c.opts.AllowFail {
+			return err
 		}
+		if err = DefaultAfterLoad(ctx, c); err != nil && !c.opts.AllowFail {
+			return err
+		}
+	}
+
+	if err = fillValues(reflect.ValueOf(src), c.opts.StructTag); err == nil {
+		err = mergo.Merge(dst, src, mopts...)
 	}
 
 	if err != nil && !c.opts.AllowFail {
 		return err
 	}
 
-	for _, fn := range c.opts.AfterLoad {
-		if err := fn(ctx, c); err != nil && !c.opts.AllowFail {
-			return err
-		}
+	if err := DefaultAfterLoad(ctx, c); err != nil && !c.opts.AllowFail {
+		return err
 	}
 
 	return nil
@@ -72,6 +112,7 @@ func fillValue(value reflect.Value, val string) error {
 	if !rutil.IsEmpty(value) {
 		return nil
 	}
+
 	switch value.Kind() {
 	case reflect.Map:
 		t := value.Type()
@@ -110,6 +151,20 @@ func fillValue(value reflect.Value, val string) error {
 		}
 		value.Set(reflect.ValueOf(v))
 	case reflect.String:
+		switch val {
+		case "micro:generate uuid":
+			uid, err := uuid.NewRandom()
+			if err != nil {
+				return err
+			}
+			val = uid.String()
+		case "micro:generate id":
+			uid, err := mid.New()
+			if err != nil {
+				return err
+			}
+			val = uid
+		}
 		value.Set(reflect.ValueOf(val))
 	case reflect.Float32:
 		v, err := strconv.ParseFloat(val, 32)
@@ -148,11 +203,26 @@ func fillValue(value reflect.Value, val string) error {
 		}
 		value.Set(reflect.ValueOf(int32(v)))
 	case reflect.Int64:
-		v, err := strconv.ParseInt(val, 10, 64)
-		if err != nil {
-			return err
+		switch {
+		case value.Type().String() == "time.Duration" && value.Type().PkgPath() == "time":
+			v, err := time.ParseDuration(val)
+			if err != nil {
+				return err
+			}
+			value.Set(reflect.ValueOf(v))
+		case value.Type().String() == "time.Duration" && value.Type().PkgPath() == "go.unistack.org/micro/v4/util/time":
+			v, err := mtime.ParseDuration(val)
+			if err != nil {
+				return err
+			}
+			value.SetInt(int64(v))
+		default:
+			v, err := strconv.ParseInt(val, 10, 64)
+			if err != nil {
+				return err
+			}
+			value.Set(reflect.ValueOf(v))
 		}
-		value.Set(reflect.ValueOf(v))
 	case reflect.Uint:
 		v, err := strconv.ParseUint(val, 10, 0)
 		if err != nil {
@@ -184,6 +254,7 @@ func fillValue(value reflect.Value, val string) error {
 		}
 		value.Set(reflect.ValueOf(v))
 	}
+
 	return nil
 }
 
@@ -247,16 +318,20 @@ func fillValues(valueOf reflect.Value, tname string) error {
 }
 
 func (c *defaultConfig) Save(ctx context.Context, opts ...SaveOption) error {
-	for _, fn := range c.opts.BeforeSave {
-		if err := fn(ctx, c); err != nil && !c.opts.AllowFail {
-			return err
-		}
+	return c.funcSave(ctx, opts...)
+}
+
+func (c *defaultConfig) fnSave(ctx context.Context, opts ...SaveOption) error {
+	if c.opts.SkipSave != nil && c.opts.SkipSave(ctx, c) {
+		return nil
 	}
 
-	for _, fn := range c.opts.AfterSave {
-		if err := fn(ctx, c); err != nil && !c.opts.AllowFail {
-			return err
-		}
+	if err := DefaultBeforeSave(ctx, c); err != nil {
+		return err
+	}
+
+	if err := DefaultAfterSave(ctx, c); err != nil {
+		return err
 	}
 
 	return nil
@@ -270,8 +345,8 @@ func (c *defaultConfig) Name() string {
 	return c.opts.Name
 }
 
-func (c *defaultConfig) Watch(ctx context.Context, opts ...WatchOption) (Watcher, error) {
-	return nil, fmt.Errorf("not implemented")
+func (c *defaultConfig) Watch(_ context.Context, _ ...WatchOption) (Watcher, error) {
+	return nil, ErrWatcherNotImplemented
 }
 
 // NewConfig returns new default config source
@@ -280,5 +355,9 @@ func NewConfig(opts ...Option) Config {
 	if len(options.StructTag) == 0 {
 		options.StructTag = "default"
 	}
-	return &defaultConfig{opts: options}
+	c := &defaultConfig{opts: options}
+	c.funcLoad = c.fnLoad
+	c.funcSave = c.fnSave
+
+	return c
 }

config/default_test.go

@@ -3,35 +3,90 @@ package config_test
 import (
 	"context"
 	"fmt"
+	"reflect"
 	"testing"
+	"time"
 
-	"github.com/unistack-org/micro/v3/config"
+	"go.unistack.org/micro/v4/config"
+	mtime "go.unistack.org/micro/v4/util/time"
 )
 
-type Cfg struct {
+type cfg struct {
+	MapValue    map[string]bool `default:"key1=true,key2=false"`
+	StructValue *cfgStructValue
+
 	StringValue string `default:"string_value"`
 	IgnoreValue string `json:"-"`
-	StructValue struct {
-		StringValue string `default:"string_value"`
+	UUIDValue   string `default:"micro:generate uuid"`
+	IDValue     string `default:"micro:generate id"`
+
+	DurationValue  time.Duration  `default:"10s"`
+	MDurationValue mtime.Duration `default:"10s"`
+	IntValue       int            `default:"99"`
+}
+
+type cfgStructValue struct {
+	StringValue string `default:"string_value"`
+}
+
+func (c *cfg) Validate() error {
+	if c.IntValue != 10 {
+		return fmt.Errorf("invalid IntValue %d != %d", 10, c.IntValue)
+	}
+	return nil
+}
+
+func (c *cfgStructValue) Validate() error {
+	if c.StringValue != "string_value" {
+		return fmt.Errorf("invalid StringValue %s != %s", "string_value", c.StringValue)
+	}
+	return nil
+}
+
+type testHook struct {
+	f bool
+}
+
+func (t *testHook) Load(fn config.FuncLoad) config.FuncLoad {
+	return func(ctx context.Context, opts ...config.LoadOption) error {
+		t.f = true
+		return fn(ctx, opts...)
+	}
+}
+
+func TestHook(t *testing.T) {
+	h := &testHook{}
+
+	c := config.NewConfig(config.Struct(h), config.Hooks(config.HookLoad(h.Load)))
+
+	if err := c.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := c.Load(context.TODO()); err != nil {
+		t.Fatal(err)
+	}
+
+	if !h.f {
+		t.Fatal("hook not works")
 	}
-	IntValue int `default:"99"`
 }
 
 func TestDefault(t *testing.T) {
 	ctx := context.Background()
-	conf := &Cfg{IntValue: 10}
-	blfn := func(ctx context.Context, cfg config.Config) error {
-		nconf, ok := cfg.Options().Struct.(*Cfg)
+	conf := &cfg{IntValue: 10}
+	blfn := func(_ context.Context, c config.Config) error {
+		nconf, ok := c.Options().Struct.(*cfg)
 		if !ok {
-			return fmt.Errorf("failed to get Struct from options: %v", cfg.Options())
+			return fmt.Errorf("failed to get Struct from options: %v", c.Options())
 		}
 		nconf.StringValue = "before_load"
 		return nil
 	}
-	alfn := func(ctx context.Context, cfg config.Config) error {
-		nconf, ok := cfg.Options().Struct.(*Cfg)
+	alfn := func(_ context.Context, c config.Config) error {
+		nconf, ok := c.Options().Struct.(*cfg)
 		if !ok {
-			return fmt.Errorf("failed to get Struct from options: %v", cfg.Options())
+			return fmt.Errorf("failed to get Struct from options: %v", c.Options())
 		}
 		nconf.StringValue = "after_load"
 		return nil
@@ -47,6 +102,45 @@ func TestDefault(t *testing.T) {
 	if conf.StringValue != "after_load" {
 		t.Fatal("AfterLoad option not working")
 	}
+	if len(conf.MapValue) != 2 {
+		t.Fatalf("map value invalid: %#+v\n", conf.MapValue)
+	}
+
+	if conf.UUIDValue == "" {
+		t.Fatalf("uuid value empty")
+	} else if len(conf.UUIDValue) != 36 {
+		t.Fatalf("uuid value invalid: %s", conf.UUIDValue)
+	}
+
+	if conf.IDValue == "" {
+		t.Fatalf("id value empty")
+	}
 	_ = conf
-	//t.Logf("%#+v\n", conf)
+	// t.Logf("%#+v\n", conf)
+}
+
+func TestValidate(t *testing.T) {
+	ctx := context.Background()
+	conf := &cfg{IntValue: 10}
+	cfg := config.NewConfig(config.Struct(conf))
+	if err := cfg.Init(); err != nil {
+		t.Fatal(err)
+	}
+	if err := cfg.Load(ctx); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := config.Validate(ctx, conf); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func Test_SizeOf(t *testing.T) {
+	st := cfg{}
+
+	tVal := reflect.TypeOf(st)
+	for i := 0; i < tVal.NumField(); i++ {
+		field := tVal.Field(i)
+		fmt.Printf("Field: %s, Offset: %d, Size: %d\n", field.Name, field.Offset, field.Type.Size())
+	}
 }

config/options.go

@@ -4,10 +4,11 @@ import (
 	"context"
 	"time"
 
-	"github.com/unistack-org/micro/v3/codec"
-	"github.com/unistack-org/micro/v3/logger"
-	"github.com/unistack-org/micro/v3/meter"
-	"github.com/unistack-org/micro/v3/tracer"
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/logger"
+	"go.unistack.org/micro/v4/meter"
+	"go.unistack.org/micro/v4/options"
+	"go.unistack.org/micro/v4/tracer"
 )
 
 // Options hold the config options
@@ -28,14 +29,26 @@ type Options struct {
 	Name string
 	// StructTag name
 	StructTag string
-	// BeforeSave contains slice of funcs that runs before save
+	// BeforeSave contains slice of funcs that runs before Save
 	BeforeSave []func(context.Context, Config) error
-	// AfterLoad contains slice of funcs that runs after load
-	AfterLoad []func(context.Context, Config) error
-	// BeforeLoad contains slice of funcs that runs before load
-	BeforeLoad []func(context.Context, Config) error
-	// AfterSave contains slice of funcs that runs after save
+	// AfterSave contains slice of funcs that runs after Save
 	AfterSave []func(context.Context, Config) error
+	// BeforeLoad contains slice of funcs that runs before Load
+	BeforeLoad []func(context.Context, Config) error
+	// AfterLoad contains slice of funcs that runs after Load
+	AfterLoad []func(context.Context, Config) error
+	// BeforeInit contains slice of funcs that runs before Init
+	BeforeInit []func(context.Context, Config) error
+	// AfterInit contains slice of funcs that runs after Init
+	AfterInit []func(context.Context, Config) error
+
+	// SkipLoad runs only if condition returns true
+	SkipLoad func(context.Context, Config) bool
+	// SkipSave runs only if condition returns true
+	SkipSave func(context.Context, Config) bool
+	// Hooks can be run before/after config Save/Load
+	Hooks options.Hooks
+
 	// AllowFail flag to allow fail in config source
 	AllowFail bool
 }
@@ -64,10 +77,12 @@ type LoadOption func(o *LoadOptions)
 // LoadOptions struct
 type LoadOptions struct {
 	Struct   interface{}
+	Context  context.Context
 	Override bool
 	Append   bool
 }
 
+// NewLoadOptions create LoadOptions struct with provided opts
 func NewLoadOptions(opts ...LoadOption) LoadOptions {
 	options := LoadOptions{}
 	for _, o := range opts {
@@ -102,7 +117,8 @@ type SaveOption func(o *SaveOptions)
 
 // SaveOptions struct
 type SaveOptions struct {
-	Struct interface{}
+	Struct  interface{}
+	Context context.Context
 }
 
 // SaveStruct override struct for save to config
@@ -128,6 +144,20 @@ func AllowFail(b bool) Option {
 	}
 }
 
+// BeforeInit run funcs before config Init
+func BeforeInit(fn ...func(context.Context, Config) error) Option {
+	return func(o *Options) {
+		o.BeforeInit = fn
+	}
+}
+
+// AfterInit run funcs after config Init
+func AfterInit(fn ...func(context.Context, Config) error) Option {
+	return func(o *Options) {
+		o.AfterInit = fn
+	}
+}
+
 // BeforeLoad run funcs before config load
 func BeforeLoad(fn ...func(context.Context, Config) error) Option {
 	return func(o *Options) {
@@ -209,18 +239,20 @@ func Name(n string) Option {
 type WatchOptions struct {
 	// Context used by non default options
 	Context context.Context
-	// Coalesce multiple events to one
-	Coalesce bool
+	// Struct for filling
+	Struct interface{}
 	// MinInterval specifies the min time.Duration interval for poll changes
 	MinInterval time.Duration
 	// MaxInterval specifies the max time.Duration interval for poll changes
 	MaxInterval time.Duration
-	// Struct for filling
-	Struct interface{}
+	// Coalesce multiple events to one
+	Coalesce bool
 }
 
+// WatchOption func signature
 type WatchOption func(*WatchOptions)
 
+// NewWatchOptions create WatchOptions struct with provided opts
 func NewWatchOptions(opts ...WatchOption) WatchOptions {
 	options := WatchOptions{
 		Context:     context.Background(),
@@ -248,10 +280,10 @@ func WatchCoalesce(b bool) WatchOption {
 }
 
 // WatchInterval specifies min and max time.Duration for pulling changes
-func WatchInterval(min, max time.Duration) WatchOption {
+func WatchInterval(minTime, maxTime time.Duration) WatchOption {
 	return func(o *WatchOptions) {
-		o.MinInterval = min
-		o.MaxInterval = max
+		o.MinInterval = minTime
+		o.MaxInterval = maxTime
 	}
 }
 
@@ -261,3 +293,10 @@ func WatchStruct(src interface{}) WatchOption {
 		o.Struct = src
 	}
 }
+
+// Hooks sets hook runs before action
+func Hooks(h ...options.Hook) Option {
+	return func(o *Options) {
+		o.Hooks = append(o.Hooks, h...)
+	}
+}

context_test.go

@@ -0,0 +1,24 @@
+package micro
+
+import (
+	"context"
+	"testing"
+)
+
+func TestFromContext(t *testing.T) {
+	ctx := context.WithValue(context.TODO(), serviceKey{}, NewService())
+
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("FromContext not works")
+	}
+}
+
+func TestNewContext(t *testing.T) {
+	ctx := NewContext(context.TODO(), NewService())
+
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("NewContext not works")
+	}
+}

database/dsn.go

@@ -0,0 +1,157 @@
+package database
+
+import (
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"net/url"
+	"strings"
+)
+
+var (
+	ErrInvalidDSNAddr      = errors.New("invalid dsn addr")
+	ErrInvalidDSNUnescaped = errors.New("dsn must be escaped")
+	ErrInvalidDSNNoSlash   = errors.New("dsn must contains slash")
+)
+
+type Config struct {
+	TLSConfig *tls.Config
+	Username  string
+	Password  string
+	Scheme    string
+	Host      string
+	Port      string
+	Database  string
+	Params    []string
+}
+
+func (cfg *Config) FormatDSN() string {
+	var s strings.Builder
+
+	if len(cfg.Scheme) > 0 {
+		s.WriteString(cfg.Scheme + "://")
+	}
+	// [username[:password]@]
+	if len(cfg.Username) > 0 {
+		s.WriteString(cfg.Username)
+		if len(cfg.Password) > 0 {
+			s.WriteByte(':')
+			s.WriteString(url.PathEscape(cfg.Password))
+		}
+		s.WriteByte('@')
+	}
+
+	// [host:port]
+	if len(cfg.Host) > 0 {
+		s.WriteString(cfg.Host)
+		if len(cfg.Port) > 0 {
+			s.WriteByte(':')
+			s.WriteString(cfg.Port)
+		}
+	}
+
+	// /dbname
+	s.WriteByte('/')
+	s.WriteString(url.PathEscape(cfg.Database))
+
+	for i := 0; i < len(cfg.Params); i += 2 {
+		if i == 0 {
+			s.WriteString("?")
+		} else {
+			s.WriteString("&")
+		}
+		s.WriteString(cfg.Params[i])
+		s.WriteString("=")
+		s.WriteString(cfg.Params[i+1])
+	}
+
+	return s.String()
+}
+
+func ParseDSN(dsn string) (*Config, error) {
+	cfg := &Config{}
+
+	// [user[:password]@][net[(addr)]]/dbname[?param1=value1&paramN=valueN]
+	// Find last '/' that goes before dbname
+	foundSlash := false
+	for i := len(dsn) - 1; i >= 0; i-- {
+		if dsn[i] == '/' {
+			foundSlash = true
+			var j, k int
+
+			// left part is empty if i <= 0
+			if i > 0 {
+				// Find the first ':' in dsn
+				for j = i; j >= 0; j-- {
+					if dsn[j] == ':' {
+						cfg.Scheme = dsn[0:j]
+					}
+				}
+
+				// [username[:password]@][host]
+				// Find the last '@' in dsn[:i]
+				for j = i; j >= 0; j-- {
+					if dsn[j] == '@' {
+						// username[:password]
+						// Find the second ':' in dsn[:j]
+						for k = 0; k < j; k++ {
+							if dsn[k] == ':' {
+								if cfg.Scheme == dsn[:k] {
+									continue
+								}
+								var err error
+								cfg.Password, err = url.PathUnescape(dsn[k+1 : j])
+								if err != nil {
+									return nil, err
+								}
+								break
+							}
+						}
+						cfg.Username = dsn[len(cfg.Scheme)+3 : k]
+						break
+					}
+				}
+
+				for k = j + 1; k < i; k++ {
+					if dsn[k] == ':' {
+						cfg.Host = dsn[j+1 : k]
+						cfg.Port = dsn[k+1 : i]
+						break
+					}
+				}
+
+			}
+
+			// dbname[?param1=value1&...&paramN=valueN]
+			// Find the first '?' in dsn[i+1:]
+			for j = i + 1; j < len(dsn); j++ {
+				if dsn[j] == '?' {
+					parts := strings.Split(dsn[j+1:], "&")
+					cfg.Params = make([]string, 0, len(parts)*2)
+					for _, p := range parts {
+						k, v, found := strings.Cut(p, "=")
+						if !found {
+							continue
+						}
+						cfg.Params = append(cfg.Params, k, v)
+					}
+
+					break
+				}
+			}
+			var err error
+			dbname := dsn[i+1 : j]
+			if cfg.Database, err = url.PathUnescape(dbname); err != nil {
+				return nil, fmt.Errorf("invalid dbname %q: %w", dbname, err)
+			}
+
+			break
+		}
+	}
+
+	if !foundSlash && len(dsn) > 0 {
+		return nil, ErrInvalidDSNNoSlash
+	}
+
+	return cfg, nil
+}

database/dsn_test.go

@@ -0,0 +1,31 @@
+package database
+
+import (
+	"net/url"
+	"testing"
+)
+
+func TestParseDSN(t *testing.T) {
+	cfg, err := ParseDSN("postgres://username:p@ssword#@host:12345/dbname?key1=val2&key2=val2")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if cfg.Password != "p@ssword#" {
+		t.Fatalf("parsing error")
+	}
+}
+
+func TestFormatDSN(t *testing.T) {
+	src := "postgres://username:p@ssword#@host:12345/dbname?key1=val2&key2=val2"
+	cfg, err := ParseDSN(src)
+	if err != nil {
+		t.Fatal(err)
+	}
+	dst, err := url.PathUnescape(cfg.FormatDSN())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if src != dst {
+		t.Fatalf("\n%s\n%s", src, dst)
+	}
+}

errors/errors.go

@@ -3,9 +3,18 @@
 package errors
 
 import (
+	"bytes"
+	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
+	"io"
 	"net/http"
+	"strconv"
+	"strings"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 )
 
 var (
@@ -35,10 +44,24 @@ var (
 	ErrGatewayTimeout = &Error{Code: 504}
 )
 
+const ProblemContentType = "application/problem+json"
+
+type Problem struct {
+	Type     string `json:"type,omitempty"`
+	Title    string `json:"title,omitempty"`
+	Detail   string `json:"detail,omitempty"`
+	Instance string `json:"instance,omitempty"`
+	Errors   []struct {
+		Title  string `json:"title,omitempty"`
+		Detail string `json:"detail,omitempty"`
+	} `json:"errors,omitempty"`
+	Status int `json:"status,omitempty"`
+}
+
 // Error type
 type Error struct {
-	// Id holds error id or service, usually someting like my_service or uuid
-	Id string
+	// ID holds error id or service, usually someting like my_service or id
+	ID string
 	// Detail holds some useful details about error
 	Detail string
 	// Status usually holds text of http status
@@ -53,10 +76,26 @@ func (e *Error) Error() string {
 	return string(b)
 }
 
+/*
+// Generator struct holds id of error
+type Generator struct {
+	id string
+}
+
+// Generator can emit new error with static id
+func NewGenerator(id string) *Generator {
+	return &Generator{id: id}
+}
+
+func (g *Generator) BadRequest(format string, args ...interface{}) error {
+	return BadRequest(g.id, format, args...)
+}
+*/
+
 // New generates a custom error
 func New(id, detail string, code int32) error {
 	return &Error{
-		Id:     id,
+		ID:     id,
 		Code:   code,
 		Detail: detail,
 		Status: http.StatusText(int(code)),
@@ -66,130 +105,130 @@ func New(id, detail string, code int32) error {
 // Parse tries to parse a JSON string into an error. If that
 // fails, it will set the given string as the error detail.
 func Parse(err string) *Error {
-	e := new(Error)
-	errr := json.Unmarshal([]byte(err), e)
-	if errr != nil {
+	e := &Error{}
+	nerr := json.Unmarshal([]byte(err), e)
+	if nerr != nil {
 		e.Detail = err
 	}
 	return e
 }
 
 // BadRequest generates a 400 error.
-func BadRequest(id, format string, a ...interface{}) error {
+func BadRequest(id, format string, args ...interface{}) error {
 	return &Error{
-		Id:     id,
+		ID:     id,
 		Code:   400,
-		Detail: fmt.Sprintf(format, a...),
+		Detail: fmt.Sprintf(format, args...),
 		Status: http.StatusText(400),
 	}
 }
 
 // Unauthorized generates a 401 error.
-func Unauthorized(id, format string, a ...interface{}) error {
+func Unauthorized(id, format string, args ...interface{}) error {
 	return &Error{
-		Id:     id,
+		ID:     id,
 		Code:   401,
-		Detail: fmt.Sprintf(format, a...),
+		Detail: fmt.Sprintf(format, args...),
 		Status: http.StatusText(401),
 	}
 }
 
 // Forbidden generates a 403 error.
-func Forbidden(id, format string, a ...interface{}) error {
+func Forbidden(id, format string, args ...interface{}) error {
 	return &Error{
-		Id:     id,
+		ID:     id,
 		Code:   403,
-		Detail: fmt.Sprintf(format, a...),
+		Detail: fmt.Sprintf(format, args...),
 		Status: http.StatusText(403),
 	}
 }
 
 // NotFound generates a 404 error.
-func NotFound(id, format string, a ...interface{}) error {
+func NotFound(id, format string, args ...interface{}) error {
 	return &Error{
-		Id:     id,
+		ID:     id,
 		Code:   404,
-		Detail: fmt.Sprintf(format, a...),
+		Detail: fmt.Sprintf(format, args...),
 		Status: http.StatusText(404),
 	}
 }
 
 // MethodNotAllowed generates a 405 error.
-func MethodNotAllowed(id, format string, a ...interface{}) error {
+func MethodNotAllowed(id, format string, args ...interface{}) error {
 	return &Error{
-		Id:     id,
+		ID:     id,
 		Code:   405,
-		Detail: fmt.Sprintf(format, a...),
+		Detail: fmt.Sprintf(format, args...),
 		Status: http.StatusText(405),
 	}
 }
 
 // Timeout generates a 408 error.
-func Timeout(id, format string, a ...interface{}) error {
+func Timeout(id, format string, args ...interface{}) error {
 	return &Error{
-		Id:     id,
+		ID:     id,
 		Code:   408,
-		Detail: fmt.Sprintf(format, a...),
+		Detail: fmt.Sprintf(format, args...),
 		Status: http.StatusText(408),
 	}
 }
 
 // Conflict generates a 409 error.
-func Conflict(id, format string, a ...interface{}) error {
+func Conflict(id, format string, args ...interface{}) error {
 	return &Error{
-		Id:     id,
+		ID:     id,
 		Code:   409,
-		Detail: fmt.Sprintf(format, a...),
+		Detail: fmt.Sprintf(format, args...),
 		Status: http.StatusText(409),
 	}
 }
 
 // InternalServerError generates a 500 error.
-func InternalServerError(id, format string, a ...interface{}) error {
+func InternalServerError(id, format string, args ...interface{}) error {
 	return &Error{
-		Id:     id,
+		ID:     id,
 		Code:   500,
-		Detail: fmt.Sprintf(format, a...),
+		Detail: fmt.Sprintf(format, args...),
 		Status: http.StatusText(500),
 	}
 }
 
 // NotImplemented generates a 501 error
-func NotImplemented(id, format string, a ...interface{}) error {
+func NotImplemented(id, format string, args ...interface{}) error {
 	return &Error{
-		Id:     id,
+		ID:     id,
 		Code:   501,
-		Detail: fmt.Sprintf(format, a...),
+		Detail: fmt.Sprintf(format, args...),
 		Status: http.StatusText(501),
 	}
 }
 
 // BadGateway generates a 502 error
-func BadGateway(id, format string, a ...interface{}) error {
+func BadGateway(id, format string, args ...interface{}) error {
 	return &Error{
-		Id:     id,
+		ID:     id,
 		Code:   502,
-		Detail: fmt.Sprintf(format, a...),
+		Detail: fmt.Sprintf(format, args...),
 		Status: http.StatusText(502),
 	}
 }
 
 // ServiceUnavailable generates a 503 error
-func ServiceUnavailable(id, format string, a ...interface{}) error {
+func ServiceUnavailable(id, format string, args ...interface{}) error {
 	return &Error{
-		Id:     id,
+		ID:     id,
 		Code:   503,
-		Detail: fmt.Sprintf(format, a...),
+		Detail: fmt.Sprintf(format, args...),
 		Status: http.StatusText(503),
 	}
 }
 
 // GatewayTimeout generates a 504 error
-func GatewayTimeout(id, format string, a ...interface{}) error {
+func GatewayTimeout(id, format string, args ...interface{}) error {
 	return &Error{
-		Id:     id,
+		ID:     id,
 		Code:   504,
-		Detail: fmt.Sprintf(format, a...),
+		Detail: fmt.Sprintf(format, args...),
 		Status: http.StatusText(504),
 	}
 }
@@ -214,11 +253,246 @@ func Equal(err1 error, err2 error) bool {
 	return true
 }
 
+// CodeIn return true if err has specified code
+func CodeIn(err interface{}, codes ...int32) bool {
+	var code int32
+	switch verr := err.(type) {
+	case *Error:
+		code = verr.Code
+	case int32:
+		code = verr
+	default:
+		return false
+	}
+
+	for _, check := range codes {
+		if code == check {
+			return true
+		}
+	}
+
+	return false
+}
+
 // FromError try to convert go error to *Error
 func FromError(err error) *Error {
+	if err == nil {
+		return nil
+	}
+
 	if verr, ok := err.(*Error); ok && verr != nil {
 		return verr
 	}
 
 	return Parse(err.Error())
 }
+
+// MarshalJSON returns error data
+func (e *Error) MarshalJSON() ([]byte, error) {
+	return e.Marshal()
+}
+
+// UnmarshalJSON set error data
+func (e *Error) UnmarshalJSON(data []byte) error {
+	return e.Unmarshal(data)
+}
+
+// ProtoMessage noop func
+func (e *Error) ProtoMessage() {}
+
+// Reset resets error
+func (e *Error) Reset() {
+	*e = Error{}
+}
+
+// String returns error as string
+func (e *Error) String() string {
+	return fmt.Sprintf(`{"id":"%s","detail":"%s","status":"%s","code":%d}`, addslashes(e.ID), addslashes(e.Detail), addslashes(e.Status), e.Code)
+}
+
+// Marshal returns error data
+func (e *Error) Marshal() ([]byte, error) {
+	return []byte(e.String()), nil
+}
+
+// Unmarshal set error data
+func (e *Error) Unmarshal(data []byte) error {
+	str := string(data)
+	if len(data) < 41 {
+		return fmt.Errorf("invalid data")
+	}
+	parts := strings.FieldsFunc(str[1:len(str)-1], func(r rune) bool {
+		return r == ','
+	})
+	for _, part := range parts {
+		nparts := strings.FieldsFunc(part, func(r rune) bool {
+			return r == ':'
+		})
+		for idx := 0; idx < len(nparts)/2; idx += 2 {
+			val := strings.Trim(nparts[idx+1], `"`)
+			if len(val) == 0 {
+				continue
+			}
+			switch {
+			case nparts[idx] == `"id"`:
+				e.ID = val
+			case nparts[idx] == `"detail"`:
+				e.Detail = val
+			case nparts[idx] == `"status"`:
+				e.Status = val
+			case nparts[idx] == `"code"`:
+				c, err := strconv.ParseInt(val, 10, 32)
+				if err != nil {
+					return err
+				}
+				e.Code = int32(c)
+			}
+			idx++
+		}
+	}
+	return nil
+}
+
+func addslashes(str string) string {
+	var buf bytes.Buffer
+	for _, char := range str {
+		switch char {
+		case '\'', '"', '\\':
+			buf.WriteRune('\\')
+		}
+		buf.WriteRune(char)
+	}
+	return buf.String()
+}
+
+type retryableError struct {
+	err error
+}
+
+// Retryable returns error that can be retried later
+func Retryable(err error) error {
+	return &retryableError{err: err}
+}
+
+type IsRetryableFunc func(error) bool
+
+var (
+	RetrayableOracleErrors = []IsRetryableFunc{
+		func(err error) bool {
+			errmsg := err.Error()
+			switch {
+			case strings.Contains(errmsg, `ORA-`):
+				return true
+			case strings.Contains(errmsg, `can not assign`):
+				return true
+			case strings.Contains(errmsg, `can't assign`):
+				return true
+			}
+			return false
+		},
+	}
+	RetrayablePostgresErrors = []IsRetryableFunc{
+		func(err error) bool {
+			errmsg := err.Error()
+			switch {
+			case strings.Contains(errmsg, `number of field descriptions must equal number of`):
+				return true
+			case strings.Contains(errmsg, `not a pointer`):
+				return true
+			case strings.Contains(errmsg, `values, but dst struct has only`):
+				return true
+			case strings.Contains(errmsg, `struct doesn't have corresponding row field`):
+				return true
+			case strings.Contains(errmsg, `cannot find field`):
+				return true
+			case strings.Contains(errmsg, `cannot scan`) || strings.Contains(errmsg, `cannot convert`):
+				return true
+			case strings.Contains(errmsg, `failed to connect to`):
+				return true
+			}
+			return false
+		},
+	}
+	RetryableMicroErrors = []IsRetryableFunc{
+		func(err error) bool {
+			switch verr := err.(type) {
+			case *Error:
+				switch verr.Code {
+				case 401, 403, 408, 500, 501, 502, 503, 504:
+					return true
+				default:
+					return false
+				}
+			case *retryableError:
+				return true
+			}
+			return false
+		},
+	}
+	RetryableGoErrors = []IsRetryableFunc{
+		func(err error) bool {
+			switch verr := err.(type) {
+			case interface{ SafeToRetry() bool }:
+				return verr.SafeToRetry()
+			case interface{ Timeout() bool }:
+				return verr.Timeout()
+			}
+			switch {
+			case errors.Is(err, io.EOF), errors.Is(err, io.ErrUnexpectedEOF):
+				return true
+			case errors.Is(err, context.DeadlineExceeded):
+				return true
+			case errors.Is(err, io.ErrClosedPipe), errors.Is(err, io.ErrShortBuffer), errors.Is(err, io.ErrShortWrite):
+				return true
+			}
+			return false
+		},
+	}
+	RetryableGrpcErrors = []IsRetryableFunc{
+		func(err error) bool {
+			st, ok := status.FromError(err)
+			if !ok {
+				return false
+			}
+			switch st.Code() {
+			case codes.Unavailable, codes.ResourceExhausted:
+				return true
+			case codes.DeadlineExceeded:
+				return true
+			case codes.Internal:
+				switch {
+				case strings.Contains(st.Message(), `transport: received the unexpected content-type "text/html; charset=UTF-8"`):
+					return true
+				case strings.Contains(st.Message(), io.ErrUnexpectedEOF.Error()):
+					return true
+				case strings.Contains(st.Message(), `stream terminated by RST_STREAM with error code: INTERNAL_ERROR`):
+					return true
+				}
+			}
+			return false
+		},
+	}
+)
+
+// Unwrap provides error wrapping
+func (e *retryableError) Unwrap() error {
+	return e.err
+}
+
+// Error returns the error string
+func (e *retryableError) Error() string {
+	if e.err == nil {
+		return ""
+	}
+	return e.err.Error()
+}
+
+// IsRetryable checks error for ability to retry later
+func IsRetryable(err error, fns ...IsRetryableFunc) bool {
+	for _, fn := range fns {
+		if ok := fn(err); ok {
+			return true
+		}
+	}
+	return false
+}

errors/errors.proto

@@ -0,0 +1,31 @@
+// Copyright 2021 Unistack LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+
+package micro.errors;
+
+option cc_enable_arenas = true;
+option go_package = "go.unistack.org/micro/v4/errors;errors";
+option java_multiple_files = true;
+option java_outer_classname = "MicroErrors";
+option java_package = "micro.errors";
+option objc_class_prefix = "MERRORS";
+
+message Error {
+  string id = 1;
+  string detail = 2;
+  string status = 3;
+  uint32 code = 4;
+}

errors/errors_test.go

@@ -1,20 +1,50 @@
 package errors
 
 import (
-	er "errors"
+	"encoding/json"
+	"errors"
+	"fmt"
 	"net/http"
 	"testing"
 )
 
+func TestIsRetrayable(t *testing.T) {
+	err := fmt.Errorf("ORA-")
+	if !IsRetryable(err, RetrayableOracleErrors...) {
+		t.Fatalf("IsRetrayable not works")
+	}
+}
+
+func TestMarshalJSON(t *testing.T) {
+	e := InternalServerError("id", "err: %v", fmt.Errorf("err: %v", `xxx: "UNIX_TIMESTAMP": invalid identifier`))
+	_, err := json.Marshal(e)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestEmpty(t *testing.T) {
+	msg := "test"
+	var err *Error
+	err = FromError(errors.New(msg))
+	if err.Detail != msg {
+		t.Fatalf("invalid error %v", err)
+	}
+	err = FromError(fmt.Errorf(`{"id":"","detail":"%s","status":"%s","code":0}`, msg, msg))
+	if err.Detail != msg || err.Status != msg {
+		t.Fatalf("invalid error %#+v", err)
+	}
+}
+
 func TestFromError(t *testing.T) {
 	err := NotFound("go.micro.test", "%s", "example")
 	merr := FromError(err)
-	if merr.Id != "go.micro.test" || merr.Code != 404 {
+	if merr.ID != "go.micro.test" || merr.Code != 404 {
 		t.Fatalf("invalid conversation %v != %v", err, merr)
 	}
-	err = er.New(err.Error())
+	err = errors.New(err.Error())
 	merr = FromError(err)
-	if merr.Id != "go.micro.test" || merr.Code != 404 {
+	if merr.ID != "go.micro.test" || merr.Code != 404 {
 		t.Fatalf("invalid conversation %v != %v", err, merr)
 	}
 }
@@ -27,7 +57,7 @@ func TestEqual(t *testing.T) {
 		t.Fatal("errors must be equal")
 	}
 
-	err3 := er.New("my test err")
+	err3 := errors.New("my test err")
 	if Equal(err1, err3) {
 		t.Fatal("errors must be not equal")
 	}
@@ -36,7 +66,7 @@ func TestEqual(t *testing.T) {
 func TestErrors(t *testing.T) {
 	testData := []*Error{
 		{
-			Id:     "test",
+			ID:     "test",
 			Code:   500,
 			Detail: "Internal server error",
 			Status: http.StatusText(500),
@@ -44,7 +74,7 @@ func TestErrors(t *testing.T) {
 	}
 
 	for _, e := range testData {
-		ne := New(e.Id, e.Detail, e.Code)
+		ne := New(e.ID, e.Detail, e.Code)
 
 		if e.Error() != ne.Error() {
 			t.Fatalf("Expected %s got %s", e.Error(), ne.Error())
@@ -56,8 +86,8 @@ func TestErrors(t *testing.T) {
 			t.Fatalf("Expected error got nil %v", pe)
 		}
 
-		if pe.Id != e.Id {
-			t.Fatalf("Expected %s got %s", e.Id, pe.Id)
+		if pe.ID != e.ID {
+			t.Fatalf("Expected %s got %s", e.ID, pe.ID)
 		}
 
 		if pe.Detail != e.Detail {
@@ -73,3 +103,19 @@ func TestErrors(t *testing.T) {
 		}
 	}
 }
+
+func TestCodeIn(t *testing.T) {
+	err := InternalServerError("id", "%s", "msg")
+
+	if ok := CodeIn(err, 400, 500); !ok {
+		t.Fatalf("CodeIn not works: %v", err)
+	}
+
+	if ok := CodeIn(err.(*Error).Code, 500); !ok {
+		t.Fatalf("CodeIn not works: %v", err)
+	}
+
+	if ok := CodeIn(err, 100); ok {
+		t.Fatalf("CodeIn not works: %v", err)
+	}
+}

event.go

@@ -1,27 +0,0 @@
-package micro
-
-import (
-	"context"
-
-	"github.com/unistack-org/micro/v3/client"
-)
-
-// Event is used to publish messages to a topic
-type Event interface {
-	// Publish publishes a message to the event topic
-	Publish(ctx context.Context, msg interface{}, opts ...client.PublishOption) error
-}
-
-type event struct {
-	c     client.Client
-	topic string
-}
-
-// NewEvent creates a new event publisher
-func NewEvent(topic string, c client.Client) Event {
-	return &event{c, topic}
-}
-
-func (e *event) Publish(ctx context.Context, msg interface{}, opts ...client.PublishOption) error {
-	return e.c.Publish(ctx, e.c.NewMessage(e.topic, msg), opts...)
-}

flow/context_test.go

@@ -0,0 +1,55 @@
+//go:build ignore
+
+package flow
+
+import (
+	"context"
+	"testing"
+)
+
+func TestFromNilContext(t *testing.T) {
+	// nolint: staticcheck
+	c, ok := FromContext(nil)
+	if ok || c != nil {
+		t.Fatal("FromContext not works")
+	}
+}
+
+func TestNewNilContext(t *testing.T) {
+	// nolint: staticcheck
+	ctx := NewContext(nil, NewFlow())
+
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("NewContext not works")
+	}
+}
+
+func TestFromContext(t *testing.T) {
+	ctx := context.WithValue(context.TODO(), flowKey{}, NewFlow())
+
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("FromContext not works")
+	}
+}
+
+func TestNewContext(t *testing.T) {
+	ctx := NewContext(context.TODO(), NewFlow())
+
+	c, ok := FromContext(ctx)
+	if c == nil || !ok {
+		t.Fatal("NewContext not works")
+	}
+}
+
+func TestSetOption(t *testing.T) {
+	type key struct{}
+	o := SetOption(key{}, "test")
+	opts := &Options{}
+	o(opts)
+
+	if v, ok := opts.Context.Value(key{}).(string); !ok || v == "" {
+		t.Fatal("SetOption not works")
+	}
+}

flow/dag_test.go

@@ -7,6 +7,56 @@ import (
 	"github.com/silas/dag"
 )
 
+func TestDeps(t *testing.T) {
+	t.Skip()
+	d := &dag.AcyclicGraph{}
+
+	v0 := d.Add(&node{"v0"})
+	v1 := d.Add(&node{"v1"})
+	v2 := d.Add(&node{"v2"})
+	v3 := d.Add(&node{"v3"})
+	v4 := d.Add(&node{"v4"})
+
+	d.Connect(dag.BasicEdge(v0, v1))
+	d.Connect(dag.BasicEdge(v1, v2))
+	d.Connect(dag.BasicEdge(v2, v4))
+	d.Connect(dag.BasicEdge(v0, v3))
+	d.Connect(dag.BasicEdge(v3, v4))
+
+	if err := d.Validate(); err != nil {
+		t.Fatal(err)
+	}
+
+	d.TransitiveReduction()
+
+	var steps [][]string
+	fn := func(n dag.Vertex, idx int) error {
+		if idx == 0 {
+			steps = make([][]string, 1)
+			steps[0] = make([]string, 0, 1)
+		} else if idx >= len(steps) {
+			tsteps := make([][]string, idx+1)
+			copy(tsteps, steps)
+			steps = tsteps
+			steps[idx] = make([]string, 0, 1)
+		}
+		steps[idx] = append(steps[idx], fmt.Sprintf("%s", n))
+		return nil
+	}
+
+	start := &node{"v0"}
+	err := d.SortedDepthFirstWalk([]dag.Vertex{start}, fn)
+	checkErr(t, err)
+
+	for idx, steps := range steps {
+		fmt.Printf("level %d steps %#+v\n", idx, steps)
+	}
+
+	if len(steps[2]) != 1 {
+		t.Logf("invalid steps %#+v", steps[2])
+	}
+}
+
 func checkErr(t *testing.T, err error) {
 	if err != nil {
 		t.Fatal(err)

flow/default.go

@@ -1,3 +1,5 @@
+//go:build ignore
+
 package flow
 
 import (
@@ -6,13 +8,12 @@ import (
 	"path/filepath"
 	"sync"
 
-	"github.com/google/uuid"
-	"github.com/silas/dag"
-	"github.com/unistack-org/micro/v3/client"
-	"github.com/unistack-org/micro/v3/codec"
-	"github.com/unistack-org/micro/v3/logger"
-	"github.com/unistack-org/micro/v3/metadata"
-	"github.com/unistack-org/micro/v3/store"
+	"github.com/heimdalr/dag"
+	"go.unistack.org/micro/v4/client"
+	"go.unistack.org/micro/v4/codec"
+	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v4/store"
+	"go.unistack.org/micro/v4/util/id"
 )
 
 type microFlow struct {
@@ -20,33 +21,33 @@ type microFlow struct {
 }
 
 type microWorkflow struct {
-	id   string
-	g    *dag.AcyclicGraph
-	init bool
-	sync.RWMutex
 	opts   Options
+	g      *dag.DAG
 	steps  map[string]Step
+	id     string
 	status Status
+	sync.RWMutex
+	init bool
 }
 
 func (w *microWorkflow) ID() string {
 	return w.id
 }
 
-func (w *microWorkflow) Steps() ([][]Step, error) {
-	return w.getSteps("", false)
-}
-
 func (w *microWorkflow) Status() Status {
 	return w.status
 }
 
 func (w *microWorkflow) AppendSteps(steps ...Step) error {
+	var err error
 	w.Lock()
+	defer w.Unlock()
 
 	for _, s := range steps {
 		w.steps[s.String()] = s
-		w.g.Add(s)
+		if _, err = w.g.AddVertex(s); err != nil {
+			return err
+		}
 	}
 
 	for _, dst := range steps {
@@ -55,18 +56,13 @@ func (w *microWorkflow) AppendSteps(steps ...Step) error {
 			if !ok {
 				return ErrStepNotExists
 			}
-			w.g.Connect(dag.BasicEdge(src, dst))
+			if err = w.g.AddEdge(src.String(), dst.String()); err != nil {
+				return err
+			}
 		}
 	}
 
-	if err := w.g.Validate(); err != nil {
-		w.Unlock()
-		return err
-	}
-
-	w.g.TransitiveReduction()
-
-	w.Unlock()
+	w.g.ReduceTransitively()
 
 	return nil
 }
@@ -75,10 +71,11 @@ func (w *microWorkflow) RemoveSteps(steps ...Step) error {
 	// TODO: handle case when some step requires or required by removed step
 
 	w.Lock()
+	defer w.Unlock()
 
 	for _, s := range steps {
 		delete(w.steps, s.String())
-		w.g.Remove(s)
+		w.g.DeleteVertex(s.String())
 	}
 
 	for _, dst := range steps {
@@ -87,121 +84,48 @@ func (w *microWorkflow) RemoveSteps(steps ...Step) error {
 			if !ok {
 				return ErrStepNotExists
 			}
-			w.g.Connect(dag.BasicEdge(src, dst))
+			w.g.AddEdge(src.String(), dst.String())
 		}
 	}
 
-	if err := w.g.Validate(); err != nil {
-		w.Unlock()
-		return err
-	}
-
-	w.g.TransitiveReduction()
-
-	w.Unlock()
+	w.g.ReduceTransitively()
 
 	return nil
 }
 
-func (w *microWorkflow) getSteps(start string, reverse bool) ([][]Step, error) {
-	var steps [][]Step
-	var root dag.Vertex
-	var err error
-
-	fn := func(n dag.Vertex, idx int) error {
-		if idx == 0 {
-			steps = make([][]Step, 1)
-			steps[0] = make([]Step, 0, 1)
-		} else if idx >= len(steps) {
-			tsteps := make([][]Step, idx+1)
-			copy(tsteps, steps)
-			steps = tsteps
-			steps[idx] = make([]Step, 0, 1)
-		}
-		steps[idx] = append(steps[idx], n.(Step))
-		return nil
-	}
-
-	if start != "" {
-		var ok bool
-		w.RLock()
-		root, ok = w.steps[start]
-		w.RUnlock()
-		if !ok {
-			return nil, ErrStepNotExists
-		}
-	} else {
-		root, err = w.g.Root()
-		if err != nil {
-			return nil, err
-		}
-	}
-
-	if reverse {
-		err = w.g.SortedReverseDepthFirstWalk([]dag.Vertex{root}, fn)
-	} else {
-		err = w.g.SortedDepthFirstWalk([]dag.Vertex{root}, fn)
-	}
-	if err != nil {
-		return nil, err
-	}
-
-	return steps, nil
-}
-
-func (w *microWorkflow) Abort(ctx context.Context, eid string) error {
-	workflowStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("workflows", eid))
+func (w *microWorkflow) Abort(ctx context.Context, id string) error {
+	workflowStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("workflows", id))
 	return workflowStore.Write(ctx, "status", &codec.Frame{Data: []byte(StatusAborted.String())})
 }
 
-func (w *microWorkflow) Suspend(ctx context.Context, eid string) error {
-	workflowStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("workflows", eid))
+func (w *microWorkflow) Suspend(ctx context.Context, id string) error {
+	workflowStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("workflows", id))
 	return workflowStore.Write(ctx, "status", &codec.Frame{Data: []byte(StatusSuspend.String())})
 }
 
-func (w *microWorkflow) Resume(ctx context.Context, eid string) error {
-	workflowStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("workflows", eid))
+func (w *microWorkflow) Resume(ctx context.Context, id string) error {
+	workflowStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("workflows", id))
 	return workflowStore.Write(ctx, "status", &codec.Frame{Data: []byte(StatusRunning.String())})
 }
 
 func (w *microWorkflow) Execute(ctx context.Context, req *Message, opts ...ExecuteOption) (string, error) {
 	w.Lock()
 	if !w.init {
-		if err := w.g.Validate(); err != nil {
-			w.Unlock()
-			return "", err
-		}
-		w.g.TransitiveReduction()
+		w.g.ReduceTransitively()
 		w.init = true
 	}
 	w.Unlock()
 
-	uid, err := uuid.NewRandom()
+	eid, err := id.New()
 	if err != nil {
 		return "", err
 	}
-	eid := uid.String()
 
-	stepStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("steps", eid))
+	//	stepStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("steps", eid))
 	workflowStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("workflows", eid))
 
 	options := NewExecuteOptions(opts...)
 
-	steps, err := w.getSteps(options.Start, options.Reverse)
-	if err != nil {
-		if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusPending.String())}); werr != nil {
-			w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
-		}
-		return "", err
-	}
-
-	var wg sync.WaitGroup
-	cherr := make(chan error, 1)
-	chstatus := make(chan Status, 1)
-
-	nctx, cancel := context.WithCancel(ctx)
-	defer cancel()
-
 	nopts := make([]ExecuteOption, 0, len(opts)+5)
 
 	nopts = append(nopts,
@@ -211,61 +135,193 @@ func (w *microWorkflow) Execute(ctx context.Context, req *Message, opts ...Execu
 		ExecuteMeter(w.opts.Meter),
 	)
 	nopts = append(nopts, opts...)
-	done := make(chan struct{})
 
-	if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusRunning.String())}); werr != nil {
-		w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
+	if werr := workflowStore.Write(ctx, "status", &codec.Frame{Data: []byte(StatusRunning.String())}); werr != nil {
+		w.opts.Logger.Error(ctx, "store error: %v", werr)
 		return eid, werr
 	}
-	for idx := range steps {
-		for nidx := range steps[idx] {
-			cstep := steps[idx][nidx]
-			if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "status"), &codec.Frame{Data: []byte(StatusPending.String())}); werr != nil {
-				return eid, werr
+
+	var startID string
+	if options.Start == "" {
+		mp := w.g.GetRoots()
+		if len(mp) != 1 {
+			return eid, ErrStepNotExists
+		}
+		for k := range mp {
+			startID = k
+		}
+	} else {
+		for k, v := range w.g.GetVertices() {
+			if v == options.Start {
+				startID = k
 			}
 		}
 	}
 
-	go func() {
-		for idx := range steps {
-			for nidx := range steps[idx] {
-				wStatus := &codec.Frame{}
-				if werr := workflowStore.Read(w.opts.Context, "status", wStatus); werr != nil {
-					cherr <- werr
-					return
+	if startID == "" {
+		return eid, ErrStepNotExists
+	}
+
+	if options.Async {
+		go w.handleWorkflow(startID, nopts...)
+		return eid, nil
+	}
+
+	return eid, w.handleWorkflow(startID, nopts...)
+}
+
+func (w *microWorkflow) handleWorkflow(startID string, opts ...ExecuteOption) error {
+	w.RLock()
+	defer w.RUnlock()
+
+	//	stepStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("steps", eid))
+	// workflowStore := store.NewNamespaceStore(w.opts.Store, filepath.Join("workflows", eid))
+
+	// Get IDs of all descendant vertices.
+	flowIDs, errDes := w.g.GetDescendants(startID)
+	if errDes != nil {
+		return errDes
+	}
+
+	// inputChannels provides for input channels for each of the descendant vertices (+ the start-vertex).
+	inputChannels := make(map[string]chan FlowResult, len(flowIDs)+1)
+
+	// Iterate vertex IDs and create an input channel for each of them and a single
+	// output channel for leaves. Note, this "pre-flight" is needed to ensure we
+	// really have an input channel regardless of how we traverse the tree and spawn
+	// workers.
+	leafCount := 0
+
+	for id := range flowIDs {
+
+		// Get all parents of this vertex.
+		parents, errPar := w.g.GetParents(id)
+		if errPar != nil {
+			return errPar
+		}
+
+		// Create a buffered input channel that has capacity for all parent results.
+		inputChannels[id] = make(chan FlowResult, len(parents))
+
+		if ok, err := w.g.IsLeaf(id); ok && err == nil {
+			leafCount += 1
+		}
+	}
+
+	// outputChannel caries the results of leaf vertices.
+	outputChannel := make(chan FlowResult, leafCount)
+
+	// To also process the start vertex and to have its results being passed to its
+	// children, add it to the vertex IDs. Also add an input channel for the start
+	// vertex and feed the inputs to this channel.
+	flowIDs[startID] = struct{}{}
+	inputChannels[startID] = make(chan FlowResult, len(inputs))
+	for _, i := range inputs {
+		inputChannels[startID] <- i
+	}
+
+	wg := sync.WaitGroup{}
+
+	// Iterate all vertex IDs (now incl. start vertex) and handle each worker (incl.
+	// inputs and outputs) in a separate goroutine.
+	for id := range flowIDs {
+
+		// Get all children of this vertex that later need to be notified. Note, we
+		// collect all children before the goroutine to be able to release the read
+		// lock as early as possible.
+		children, errChildren := w.g.GetChildren(id)
+		if errChildren != nil {
+			return errChildren
+		}
+
+		// Remember to wait for this goroutine.
+		wg.Add(1)
+
+		go func(id string) {
+			// Get this vertex's input channel.
+			// Note, only concurrent read here, which is fine.
+			c := inputChannels[id]
+
+			// Await all parent inputs and stuff them into a slice.
+			parentCount := cap(c)
+			parentResults := make([]FlowResult, parentCount)
+			for i := 0; i < parentCount; i++ {
+				parentResults[i] = <-c
+			}
+
+			// Execute the worker.
+			errWorker := callback(w.g, id, parentResults)
+			if errWorker != nil {
+				return errWorker
+			}
+
+			// Send this worker's FlowResult onto all children's input channels or, if it is
+			// a leaf (i.e. no children), send the result onto the output channel.
+			if len(children) > 0 {
+				for child := range children {
+					inputChannels[child] <- flowResult
 				}
-				if status := StringStatus[string(wStatus.Data)]; status != StatusRunning {
-					chstatus <- status
-					return
-				}
-				if w.opts.Logger.V(logger.TraceLevel) {
-					w.opts.Logger.Tracef(nctx, "will be executed %v", steps[idx][nidx])
-				}
-				cstep := steps[idx][nidx]
-				if len(cstep.Requires()) == 0 {
-					wg.Add(1)
-					go func(step Step) {
-						defer wg.Done()
-						if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "req"), req); werr != nil {
-							cherr <- werr
-							return
-						}
-						if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "status"), &codec.Frame{Data: []byte(StatusRunning.String())}); werr != nil {
-							cherr <- werr
-							return
-						}
-						rsp, serr := step.Execute(nctx, req, nopts...)
-						if serr != nil {
-							step.SetStatus(StatusFailure)
-							if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "rsp"), serr); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
-								w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
+			} else {
+				outputChannel <- flowResult
+			}
+
+			// "Sign off".
+			wg.Done()
+		}(id)
+	}
+
+	// Wait for all go routines to finish.
+	wg.Wait()
+
+	// Await all leaf vertex results and stuff them into a slice.
+	resultCount := cap(outputChannel)
+	results := make([]FlowResult, resultCount)
+	for i := 0; i < resultCount; i++ {
+		results[i] = <-outputChannel
+	}
+
+	/*
+		go func() {
+			for idx := range steps {
+				for nidx := range steps[idx] {
+					wStatus := &codec.Frame{}
+					if werr := workflowStore.Read(w.opts.Context, "status", wStatus); werr != nil {
+						cherr <- werr
+						return
+					}
+					if status := StringStatus[string(wStatus.Data)]; status != StatusRunning {
+						chstatus <- status
+						return
+					}
+					if w.opts.Logger.V(logger.TraceLevel) {
+						w.opts.Logger.Tracef(nctx, "will be executed %v", steps[idx][nidx])
+					}
+					cstep := steps[idx][nidx]
+					// nolint: nestif
+					if len(cstep.Requires()) == 0 {
+						wg.Add(1)
+						go func(step Step) {
+							defer wg.Done()
+							if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "req"), req); werr != nil {
+								cherr <- werr
+								return
 							}
-							if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "status"), &codec.Frame{Data: []byte(StatusFailure.String())}); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
-								w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
+							if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "status"), &codec.Frame{Data: []byte(StatusRunning.String())}); werr != nil {
+								cherr <- werr
+								return
+							}
+							rsp, serr := step.Execute(nctx, req, nopts...)
+							if serr != nil {
+								step.SetStatus(StatusFailure)
+								if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "rsp"), serr); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
+									w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
+								}
+								if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "status"), &codec.Frame{Data: []byte(StatusFailure.String())}); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
+									w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
+								}
+								cherr <- serr
+								return
 							}
-							cherr <- serr
-							return
-						} else {
 							if werr := stepStore.Write(ctx, filepath.Join(step.ID(), "rsp"), rsp); werr != nil {
 								w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
 								cherr <- werr
@@ -276,30 +332,29 @@ func (w *microWorkflow) Execute(ctx context.Context, req *Message, opts ...Execu
 								cherr <- werr
 								return
 							}
-						}
-					}(cstep)
-					wg.Wait()
-				} else {
-					if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "req"), req); werr != nil {
-						cherr <- werr
-						return
-					}
-					if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "status"), &codec.Frame{Data: []byte(StatusRunning.String())}); werr != nil {
-						cherr <- werr
-						return
-					}
-					rsp, serr := cstep.Execute(nctx, req, nopts...)
-					if serr != nil {
-						cstep.SetStatus(StatusFailure)
-						if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "rsp"), serr); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
-							w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
-						}
-						if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "status"), &codec.Frame{Data: []byte(StatusFailure.String())}); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
-							w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
-						}
-						cherr <- serr
-						return
+						}(cstep)
+						wg.Wait()
 					} else {
+						if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "req"), req); werr != nil {
+							cherr <- werr
+							return
+						}
+						if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "status"), &codec.Frame{Data: []byte(StatusRunning.String())}); werr != nil {
+							cherr <- werr
+							return
+						}
+						rsp, serr := cstep.Execute(nctx, req, nopts...)
+						if serr != nil {
+							cstep.SetStatus(StatusFailure)
+							if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "rsp"), serr); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
+								w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
+							}
+							if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "status"), &codec.Frame{Data: []byte(StatusFailure.String())}); werr != nil && w.opts.Logger.V(logger.ErrorLevel) {
+								w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
+							}
+							cherr <- serr
+							return
+						}
 						if werr := stepStore.Write(ctx, filepath.Join(cstep.ID(), "rsp"), rsp); werr != nil {
 							w.opts.Logger.Errorf(ctx, "store write error: %v", werr)
 							cherr <- werr
@@ -312,48 +367,45 @@ func (w *microWorkflow) Execute(ctx context.Context, req *Message, opts ...Execu
 					}
 				}
 			}
-		}
-		close(done)
-	}()
+			close(done)
+		}()
 
-	if options.Async {
-		return eid, nil
-	}
-
-	logger.Tracef(ctx, "wait for finish or error")
-	select {
-	case <-nctx.Done():
-		err = nctx.Err()
-	case cerr := <-cherr:
-		err = cerr
-	case <-done:
-		close(cherr)
-	case <-chstatus:
-		close(chstatus)
-		return uid.String(), nil
-	}
-
-	switch {
-	case nctx.Err() != nil:
-		if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusAborted.String())}); werr != nil {
-			w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
+		if options.Async {
+			return eid, nil
 		}
-		break
-	case err == nil:
-		if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusSuccess.String())}); werr != nil {
-			w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
-		}
-		break
-	case err != nil:
-		if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusFailure.String())}); werr != nil {
-			w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
-		}
-		break
-	}
 
-	return uid.String(), err
+		logger.Tracef(ctx, "wait for finish or error")
+		select {
+		case <-nctx.Done():
+			err = nctx.Err()
+		case cerr := <-cherr:
+			err = cerr
+		case <-done:
+			close(cherr)
+		case <-chstatus:
+			close(chstatus)
+			return eid, nil
+		}
+
+		switch {
+		case nctx.Err() != nil:
+			if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusAborted.String())}); werr != nil {
+				w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
+			}
+		case err == nil:
+			if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusSuccess.String())}); werr != nil {
+				w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
+			}
+		case err != nil:
+			if werr := workflowStore.Write(w.opts.Context, "status", &codec.Frame{Data: []byte(StatusFailure.String())}); werr != nil {
+				w.opts.Logger.Errorf(w.opts.Context, "store error: %v", werr)
+			}
+		}
+	*/
+	return err
 }
 
+// NewFlow create new flow
 func NewFlow(opts ...Option) Flow {
 	options := NewOptions(opts...)
 	return &microFlow{opts: options}
@@ -390,11 +442,11 @@ func (f *microFlow) WorkflowList(ctx context.Context) ([]Workflow, error) {
 }
 
 func (f *microFlow) WorkflowCreate(ctx context.Context, id string, steps ...Step) (Workflow, error) {
-	w := &microWorkflow{opts: f.opts, id: id, g: &dag.AcyclicGraph{}, steps: make(map[string]Step, len(steps))}
+	w := &microWorkflow{opts: f.opts, id: id, g: &dag.DAG{}, steps: make(map[string]Step, len(steps))}
 
 	for _, s := range steps {
 		w.steps[s.String()] = s
-		w.g.Add(s)
+		w.g.AddVertex(s)
 	}
 
 	for _, dst := range steps {
@@ -403,14 +455,11 @@ func (f *microFlow) WorkflowCreate(ctx context.Context, id string, steps ...Step
 			if !ok {
 				return nil, ErrStepNotExists
 			}
-			w.g.Connect(dag.BasicEdge(src, dst))
+			w.g.AddEdge(src.String(), dst.String())
 		}
 	}
 
-	if err := w.g.Validate(); err != nil {
-		return nil, err
-	}
-	w.g.TransitiveReduction()
+	w.g.ReduceTransitively()
 
 	w.init = true
 
@@ -430,11 +479,11 @@ func (f *microFlow) WorkflowLoad(ctx context.Context, id string) (Workflow, erro
 }
 
 type microCallStep struct {
-	opts    StepOptions
-	service string
-	method  string
 	rsp     *Message
 	req     *Message
+	service string
+	method  string
+	opts    StepOptions
 	status  Status
 }
 
@@ -500,10 +549,12 @@ func (s *microCallStep) Execute(ctx context.Context, req *Message, opts ...Execu
 	rsp := &codec.Frame{}
 	copts := []client.CallOption{client.WithRetries(0)}
 	if options.Timeout > 0 {
-		copts = append(copts, client.WithRequestTimeout(options.Timeout), client.WithDialTimeout(options.Timeout))
+		copts = append(copts,
+			client.WithRequestTimeout(options.Timeout),
+			client.WithDialTimeout(options.Timeout))
 	}
 	nctx := metadata.NewOutgoingContext(ctx, req.Header)
-	err := options.Client.Call(nctx, options.Client.NewRequest(s.service, s.method, &codec.Frame{Data: req.Body}), rsp)
+	err := options.Client.Call(nctx, options.Client.NewRequest(s.service, s.method, &codec.Frame{Data: req.Body}), rsp, copts...)
 	if err != nil {
 		return nil, err
 	}
@@ -512,10 +563,10 @@ func (s *microCallStep) Execute(ctx context.Context, req *Message, opts ...Execu
 }
 
 type microPublishStep struct {
-	opts   StepOptions
-	topic  string
 	req    *Message
 	rsp    *Message
+	topic  string
+	opts   StepOptions
 	status Status
 }
 
@@ -554,7 +605,7 @@ func (s *microPublishStep) String() string {
 	if s.opts.ID != "" {
 		return s.opts.ID
 	}
-	return fmt.Sprintf("%s", s.topic)
+	return s.topic
 }
 
 func (s *microPublishStep) Name() string {
@@ -577,11 +628,13 @@ func (s *microPublishStep) Execute(ctx context.Context, req *Message, opts ...Ex
 	return nil, nil
 }
 
+// NewCallStep create new step with client.Call
 func NewCallStep(service string, name string, method string, opts ...StepOption) Step {
 	options := NewStepOptions(opts...)
 	return &microCallStep{service: service, method: name + "." + method, opts: options}
 }
 
+// NewPublishStep create new step with client.Publish
 func NewPublishStep(topic string, opts ...StepOption) Step {
 	options := NewStepOptions(opts...)
 	return &microPublishStep{topic: topic, opts: options}

flow/flow.go

@@ -1,5 +1,5 @@
 // Package flow is an interface used for saga pattern microservice workflow
-package flow
+package flow // import "go.unistack.org/micro/v4/flow"
 
 import (
 	"context"
@@ -7,11 +7,13 @@ import (
 	"sync"
 	"sync/atomic"
 
-	"github.com/unistack-org/micro/v3/metadata"
+	"go.unistack.org/micro/v4/metadata"
 )
 
 var (
+	// ErrStepNotExists returns when step not found
 	ErrStepNotExists = errors.New("step not exists")
+	// ErrMissingClient returns when client.Client is missing
 	ErrMissingClient = errors.New("client not set")
 )
 
@@ -36,6 +38,7 @@ func (m *RawMessage) UnmarshalJSON(data []byte) error {
 	return nil
 }
 
+// Message used to transfer data between steps
 type Message struct {
 	Header metadata.Metadata
 	Body   RawMessage
@@ -67,6 +70,7 @@ type Step interface {
 	Response() *Message
 }
 
+// Status contains step current status
 type Status int
 
 func (status Status) String() string {
@@ -74,15 +78,22 @@ func (status Status) String() string {
 }
 
 const (
+	// StatusPending step waiting to start
 	StatusPending Status = iota
+	// StatusRunning step is running
 	StatusRunning
+	// StatusFailure step competed with error
 	StatusFailure
+	// StatusSuccess step completed without error
 	StatusSuccess
+	// StatusAborted step aborted while it running
 	StatusAborted
+	// StatusSuspend step suspended
 	StatusSuspend
 )
 
 var (
+	// StatusString contains map status => string
 	StatusString = map[Status]string{
 		StatusPending: "StatusPending",
 		StatusRunning: "StatusRunning",
@@ -91,6 +102,7 @@ var (
 		StatusAborted: "StatusAborted",
 		StatusSuspend: "StatusSuspend",
 	}
+	// StringStatus contains map string => status
 	StringStatus = map[string]Status{
 		"StatusPending": StatusPending,
 		"StatusRunning": StatusRunning,
@@ -113,14 +125,12 @@ type Workflow interface {
 	AppendSteps(steps ...Step) error
 	// Status returns workflow status
 	Status() Status
-	// Steps returns steps slice where parallel steps returned on the same level
-	Steps() ([][]Step, error)
 	// Suspend suspends execution
-	Suspend(ctx context.Context, eid string) error
+	Suspend(ctx context.Context, id string) error
 	// Resume resumes execution
-	Resume(ctx context.Context, eid string) error
+	Resume(ctx context.Context, id string) error
 	// Abort abort execution
-	Abort(ctx context.Context, eid string) error
+	Abort(ctx context.Context, id string) error
 }
 
 // Flow the base interface to interact with workflows
@@ -144,6 +154,7 @@ var (
 	atomicSteps atomic.Value
 )
 
+// RegisterStep register own step with workflow
 func RegisterStep(step Step) {
 	flowMu.Lock()
 	steps, _ := atomicSteps.Load().([]Step)

flow/options.go

@@ -4,11 +4,11 @@ import (
 	"context"
 	"time"
 
-	"github.com/unistack-org/micro/v3/client"
-	"github.com/unistack-org/micro/v3/logger"
-	"github.com/unistack-org/micro/v3/meter"
-	"github.com/unistack-org/micro/v3/store"
-	"github.com/unistack-org/micro/v3/tracer"
+	"go.unistack.org/micro/v4/client"
+	"go.unistack.org/micro/v4/logger"
+	"go.unistack.org/micro/v4/meter"
+	"go.unistack.org/micro/v4/store"
+	"go.unistack.org/micro/v4/tracer"
 )
 
 // Option func
@@ -70,7 +70,7 @@ func Client(c client.Client) Option {
 
 // Context specifies a context for the service.
 // Can be used to signal shutdown of the flow
-// Can be used for extra option values.
+// or can be used for extra option values.
 func Context(ctx context.Context) Option {
 	return func(o *Options) {
 		o.Context = ctx
@@ -91,13 +91,13 @@ func Store(s store.Store) Option {
 	}
 }
 
-// WorflowOption signature
+// WorkflowOption func signature
 type WorkflowOption func(*WorkflowOptions)
 
 // WorkflowOptions holds workflow options
 type WorkflowOptions struct {
-	ID      string
 	Context context.Context
+	ID      string
 }
 
 // WorkflowID set workflow id
@@ -107,6 +107,7 @@ func WorkflowID(id string) WorkflowOption {
 	}
 }
 
+// ExecuteOptions holds execute options
 type ExecuteOptions struct {
 	// Client holds the client.Client
 	Client client.Client
@@ -120,64 +121,65 @@ type ExecuteOptions struct {
 	Context context.Context
 	// Start step
 	Start string
-	// Reverse execution
-	Reverse bool
 	// Timeout for execution
 	Timeout time.Duration
 	// Async enables async execution
 	Async bool
 }
 
+// ExecuteOption func signature
 type ExecuteOption func(*ExecuteOptions)
 
+// ExecuteClient pass client.Client to ExecuteOption
 func ExecuteClient(c client.Client) ExecuteOption {
 	return func(o *ExecuteOptions) {
 		o.Client = c
 	}
 }
 
+// ExecuteTracer pass tracer.Tracer to ExecuteOption
 func ExecuteTracer(t tracer.Tracer) ExecuteOption {
 	return func(o *ExecuteOptions) {
 		o.Tracer = t
 	}
 }
 
+// ExecuteLogger pass logger.Logger to ExecuteOption
 func ExecuteLogger(l logger.Logger) ExecuteOption {
 	return func(o *ExecuteOptions) {
 		o.Logger = l
 	}
 }
 
+// ExecuteMeter pass meter.Meter to ExecuteOption
 func ExecuteMeter(m meter.Meter) ExecuteOption {
 	return func(o *ExecuteOptions) {
 		o.Meter = m
 	}
 }
 
+// ExecuteContext pass context.Context ot ExecuteOption
 func ExecuteContext(ctx context.Context) ExecuteOption {
 	return func(o *ExecuteOptions) {
 		o.Context = ctx
 	}
 }
 
-func ExecuteReverse(b bool) ExecuteOption {
-	return func(o *ExecuteOptions) {
-		o.Reverse = b
-	}
-}
-
+// ExecuteTimeout pass timeout time.Duration for execution
 func ExecuteTimeout(td time.Duration) ExecuteOption {
 	return func(o *ExecuteOptions) {
 		o.Timeout = td
 	}
 }
 
+// ExecuteAsync says that caller does not wait for execution complete
 func ExecuteAsync(b bool) ExecuteOption {
 	return func(o *ExecuteOptions) {
 		o.Async = b
 	}
 }
 
+// NewExecuteOptions create new ExecuteOptions struct
 func NewExecuteOptions(opts ...ExecuteOption) ExecuteOptions {
 	options := ExecuteOptions{
 		Client:  client.DefaultClient,
@@ -192,15 +194,18 @@ func NewExecuteOptions(opts ...ExecuteOption) ExecuteOptions {
 	return options
 }
 
+// StepOptions holds step options
 type StepOptions struct {
-	ID       string
 	Context  context.Context
-	Requires []string
 	Fallback string
+	ID       string
+	Requires []string
 }
 
+// StepOption func signature
 type StepOption func(*StepOptions)
 
+// NewStepOptions create new StepOptions struct
 func NewStepOptions(opts ...StepOption) StepOptions {
 	options := StepOptions{
 		Context: context.Background(),
@@ -211,18 +216,21 @@ func NewStepOptions(opts ...StepOption) StepOptions {
 	return options
 }
 
+// StepID sets the step id for dag
 func StepID(id string) StepOption {
 	return func(o *StepOptions) {
 		o.ID = id
 	}
 }
 
+// StepRequires specifies required steps
 func StepRequires(steps ...string) StepOption {
 	return func(o *StepOptions) {
 		o.Requires = steps
 	}
 }
 
+// StepFallback set the step to run on error
 func StepFallback(step string) StepOption {
 	return func(o *StepOptions) {
 		o.Fallback = step

fsm/default.go

@@ -0,0 +1,126 @@
+package fsm
+
+import (
+	"context"
+	"fmt"
+	"sync"
+)
+
+type state struct {
+	body interface{}
+	name string
+}
+
+var _ State = &state{}
+
+func (s *state) Name() string {
+	return s.name
+}
+
+func (s *state) Body() interface{} {
+	return s.body
+}
+
+// fsm is a finite state machine
+type fsm struct {
+	statesMap   map[string]StateFunc
+	current     string
+	statesOrder []string
+	opts        Options
+	mu          sync.Mutex
+}
+
+// NewFSM creates a new finite state machine having the specified initial state
+// with specified options
+func NewFSM(opts ...Option) FSM {
+	return &fsm{
+		statesMap: map[string]StateFunc{},
+		opts:      NewOptions(opts...),
+	}
+}
+
+// Current returns the current state
+func (f *fsm) Current() string {
+	f.mu.Lock()
+	s := f.current
+	f.mu.Unlock()
+	return s
+}
+
+// Current returns the current state
+func (f *fsm) Reset() {
+	f.mu.Lock()
+	f.current = f.opts.Initial
+	f.mu.Unlock()
+}
+
+// State adds state to fsm
+func (f *fsm) State(state string, fn StateFunc) {
+	f.mu.Lock()
+	f.statesMap[state] = fn
+	f.statesOrder = append(f.statesOrder, state)
+	f.mu.Unlock()
+}
+
+// Start runs state machine with provided data
+func (f *fsm) Start(ctx context.Context, args interface{}, opts ...Option) (interface{}, error) {
+	var err error
+
+	f.mu.Lock()
+	options := f.opts
+
+	for _, opt := range opts {
+		opt(&options)
+	}
+
+	sopts := []StateOption{StateDryRun(options.DryRun)}
+
+	cstate := options.Initial
+	states := make(map[string]StateFunc, len(f.statesMap))
+	for k, v := range f.statesMap {
+		states[k] = v
+	}
+	f.current = cstate
+	f.mu.Unlock()
+
+	var s State
+	s = &state{name: cstate, body: args}
+	nstate := s.Name()
+
+	for {
+		select {
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		default:
+			fn, ok := states[nstate]
+			if !ok {
+				return nil, fmt.Errorf(`state "%s" %w`, nstate, ErrInvalidState)
+			}
+			f.mu.Lock()
+			f.current = nstate
+			f.mu.Unlock()
+
+			// wrap the handler func
+			for i := len(options.Wrappers); i > 0; i-- {
+				fn = options.Wrappers[i-1](fn)
+			}
+
+			s, err = fn(ctx, s, sopts...)
+
+			switch {
+			case err != nil:
+				return s.Body(), err
+			case s.Name() == StateEnd:
+				return s.Body(), nil
+			case s.Name() == "":
+				for idx := range f.statesOrder {
+					if f.statesOrder[idx] == nstate && len(f.statesOrder) > idx+1 {
+						nstate = f.statesOrder[idx+1]
+					}
+				}
+			default:
+				nstate = s.Name()
+			}
+		}
+	}
+}

fsm/fsm.go

@@ -0,0 +1,29 @@
+package fsm
+
+import (
+	"context"
+	"errors"
+)
+
+var (
+	ErrInvalidState = errors.New("does not exists")
+	StateEnd        = "end"
+)
+
+type State interface {
+	Name() string
+	Body() interface{}
+}
+
+// StateWrapper wraps the StateFunc and returns the equivalent
+type StateWrapper func(StateFunc) StateFunc
+
+// StateFunc called on state transition and return next step and error
+type StateFunc func(ctx context.Context, state State, opts ...StateOption) (State, error)
+
+type FSM interface {
+	Start(context.Context, interface{}, ...Option) (interface{}, error)
+	Current() string
+	Reset()
+	State(string, StateFunc)
+}

fsm/fsm_test.go

@@ -0,0 +1,72 @@
+package fsm
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"go.unistack.org/micro/v4/logger"
+)
+
+func TestFSMStart(t *testing.T) {
+	ctx := context.TODO()
+
+	if err := logger.DefaultLogger.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	wrapper := func(next StateFunc) StateFunc {
+		return func(sctx context.Context, s State, opts ...StateOption) (State, error) {
+			sctx = logger.NewContext(sctx, logger.DefaultLogger.Fields("state", s.Name()))
+			return next(sctx, s, opts...)
+		}
+	}
+
+	f := NewFSM(InitialState("1"), WrapState(wrapper))
+	f1 := func(sctx context.Context, s State, opts ...StateOption) (State, error) {
+		_, ok := logger.FromContext(sctx)
+		if !ok {
+			t.Fatal("f1 context does not have logger")
+		}
+		args := s.Body().(map[string]interface{})
+		if v, ok := args["request"].(string); !ok || v == "" {
+			return nil, fmt.Errorf("empty request")
+		}
+		return &state{name: "", body: map[string]interface{}{"response": "state1"}}, nil
+	}
+	f2 := func(sctx context.Context, s State, opts ...StateOption) (State, error) {
+		_, ok := logger.FromContext(sctx)
+		if !ok {
+			t.Fatal("f2 context does not have logger")
+		}
+		args := s.Body().(map[string]interface{})
+		if v, ok := args["response"].(string); !ok || v == "" {
+			return nil, fmt.Errorf("empty response")
+		}
+		return &state{name: "", body: map[string]interface{}{"response": "state2"}}, nil
+	}
+	f3 := func(sctx context.Context, s State, opts ...StateOption) (State, error) {
+		_, ok := logger.FromContext(sctx)
+		if !ok {
+			t.Fatal("f3 context does not have logger")
+		}
+		args := s.Body().(map[string]interface{})
+		if v, ok := args["response"].(string); !ok || v == "" {
+			return nil, fmt.Errorf("empty response")
+		}
+		return &state{name: StateEnd, body: map[string]interface{}{"response": "state3"}}, nil
+	}
+	f.State("1", f1)
+	f.State("2", f2)
+	f.State("3", f3)
+	rsp, err := f.Start(ctx, map[string]interface{}{"request": "state"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	args := rsp.(map[string]interface{})
+	if v, ok := args["response"].(string); !ok || v == "" {
+		t.Fatalf("nil rsp: %#+v", args)
+	} else if v != "state3" {
+		t.Fatalf("invalid rsp %#+v", args)
+	}
+}

fsm/options.go

@@ -0,0 +1,52 @@
+package fsm
+
+// Options struct holding fsm options
+type Options struct {
+	// Initial state
+	Initial string
+	// Wrappers runs before state
+	Wrappers []StateWrapper
+	// DryRun mode
+	DryRun bool
+}
+
+// Option func signature
+type Option func(*Options)
+
+// StateOptions holds state options
+type StateOptions struct {
+	DryRun bool
+}
+
+// StateDryRun says that state executes in dry run mode
+func StateDryRun(b bool) StateOption {
+	return func(o *StateOptions) {
+		o.DryRun = b
+	}
+}
+
+// StateOption func signature
+type StateOption func(*StateOptions)
+
+// InitialState sets init state for state machine
+func InitialState(initial string) Option {
+	return func(o *Options) {
+		o.Initial = initial
+	}
+}
+
+// WrapState adds a state Wrapper to a list of options passed into the fsm
+func WrapState(w StateWrapper) Option {
+	return func(o *Options) {
+		o.Wrappers = append(o.Wrappers, w)
+	}
+}
+
+// NewOptions returns new Options struct filled by passed Option
+func NewOptions(opts ...Option) Options {
+	options := Options{}
+	for _, o := range opts {
+		o(&options)
+	}
+	return options
+}