Update workflows (#135)

- Rename workflows
- pr -> job_lint
- build -> job_test
- update golangci

Co-authored-by: Aleksandr Tolstikhin <atolstikhin@mtsbank.ru>
Reviewed-on: #135
Co-authored-by: Александр Толстихин <tolstihin1996@mail.ru>
Co-committed-by: Александр Толстихин <tolstihin1996@mail.ru>

.gitea/workflows/job_lint.yml

@@ -0,0 +1,29 @@
+name: lint
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+    branches:
+    - master
+    - v3
+    - v4
+
+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_test.yml

@@ -0,0 +1,34 @@
+name: test
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+    branches:
+    - master
+    - v3
+    - v4
+  push:
+    branches:
+    - master
+    - v3
+    - v4
+
+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 +1,53 @@
+name: test
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+    branches:
+    - master
+    - v3
+    - v4
+  push:
+    branches:
+    - master
+    - v3
+    - v4
+
+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/dependabot.yml

@@ -1,19 +0,0 @@
-# To get started with Dependabot version updates, you'll need to specify which
-# package ecosystems to update and where the package manifests are located.
-# Please see the documentation for all configuration options:
-# https://help.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
-
-version: 2
-updates:
-
-  # Maintain dependencies for GitHub Actions
-  - package-ecosystem: "github-actions"
-    directory: "/"
-    schedule:
-      interval: "daily"
-
-  # Maintain dependencies for Golang
-  - package-ecosystem: "gomod"
-    directory: "/"
-    schedule:
-      interval: "daily"

.github/workflows/autoapprove.yml

@@ -1,20 +0,0 @@
-name: "autoapprove"
-
-on:
-  pull_request_target:
-    types: [assigned, opened, synchronize, reopened]
-
-permissions:
-  pull-requests: write
-  contents: write
-
-jobs:
-  autoapprove:
-    runs-on: ubuntu-latest
-    steps:
-      - name: approve
-        uses: hmarr/auto-approve-action@v2
-        if: github.actor == 'vtolstov' || github.actor == 'dependabot[bot]'
-        id: approve
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/automerge.yml

@@ -1,21 +0,0 @@
-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/workflows/build.yml

@@ -1,47 +0,0 @@
-name: build
-on:
- push:
-    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@v3.1.0
-        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: v1.30
-          # 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

.github/workflows/codeql-analysis.yml

@@ -1,78 +0,0 @@
-# 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/workflows/dependabot-automerge.yml

@@ -1,27 +0,0 @@
-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@v1.3.1
-        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/workflows/pr.yml

@@ -1,47 +0,0 @@
-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@v3.1.0
-        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: v1.30
-          # 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

@@ -0,0 +1,24 @@
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+bin
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+# Go workspace file
+go.work
+
+# General
+.DS_Store
+.idea
+.vscode

.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

go.mod

@@ -3,14 +3,6 @@ module go.unistack.org/micro-client-grpc/v3
 go 1.16
 
 require (
-	github.com/google/gnostic v0.6.9 // indirect
+	go.unistack.org/micro/v3 v3.10.22
-	github.com/google/go-cmp v0.5.7 // indirect
+	google.golang.org/grpc v1.52.3
-	github.com/kr/pretty v0.2.1 // indirect
-	github.com/kr/text v0.2.0 // indirect
-	go.unistack.org/micro/v3 v3.9.7
-	golang.org/x/net v0.0.0-20220425223048-2871e0cb64e4 // indirect
-	golang.org/x/sys v0.0.0-20220429233432-b5fbb4746d32 // indirect
-	google.golang.org/genproto v0.0.0-20220429170224-98d788798c3e // indirect
-	google.golang.org/grpc v1.46.0
-	google.golang.org/protobuf v1.28.0 // indirect
 )

grpc.go

@@ -26,11 +26,11 @@ import (
 )
 
 const (
-	DefaultContentType = "application/grpc+proto"
+	DefaultContentType = "application/grpc"
 )
 
 type grpcClient struct {
-	pool *pool
+	pool *ConnPool
 	opts client.Options
 	sync.RWMutex
 	init bool
@@ -78,10 +78,15 @@ func (g *grpcClient) call(ctx context.Context, addr string, req client.Request,
 	} else {
 		header = make(map[string]string, 2)
 	}
-
+	if opts.RequestMetadata != nil {
+		for k, v := range opts.RequestMetadata {
+			header[k] = v
+		}
+	}
 	// set timeout in nanoseconds
 	header["Grpc-Timeout"] = fmt.Sprintf("%dn", opts.RequestTimeout)
 	header["timeout"] = fmt.Sprintf("%dn", opts.RequestTimeout)
+	header["content-type"] = req.ContentType()
 
 	md := gmetadata.New(header)
 	ctx = gmetadata.NewOutgoingContext(ctx, md)
@@ -93,6 +98,7 @@ func (g *grpcClient) call(ctx context.Context, addr string, req client.Request,
 
 	maxRecvMsgSize := g.maxRecvMsgSizeValue()
 	maxSendMsgSize := g.maxSendMsgSizeValue()
+	cfgService := g.serviceConfig()
 
 	var grr error
 
@@ -111,31 +117,47 @@ func (g *grpcClient) call(ctx context.Context, addr string, req client.Request,
 			grpc.MaxCallRecvMsgSize(maxRecvMsgSize),
 			grpc.MaxCallSendMsgSize(maxSendMsgSize),
 		),
+		grpc.WithDefaultServiceConfig(cfgService),
 	}
 
-	if opts := g.getGrpcDialOptions(); opts != nil {
+	if opts := g.getGrpcDialOptions(opts.Context); opts != nil {
 		grpcDialOptions = append(grpcDialOptions, opts...)
 	}
 
-	cc, err := g.pool.getConn(dialCtx, addr, grpcDialOptions...)
+	contextDialer := g.opts.ContextDialer
+	if opts.ContextDialer != nil {
+		contextDialer = opts.ContextDialer
+	}
+	if contextDialer != nil {
+		grpcDialOptions = append(grpcDialOptions, grpc.WithContextDialer(contextDialer))
+	}
+
+	cc, err := g.pool.Get(dialCtx, addr, grpcDialOptions...)
 	if err != nil {
 		return errors.InternalServerError("go.micro.client", fmt.Sprintf("Error sending request: %v", err))
 	}
 	defer func() {
 		// defer execution of release
-		g.pool.release(cc, grr)
+		g.pool.Put(cc, grr)
 	}()
 
 	ch := make(chan error, 1)
+	var gmd gmetadata.MD
+
+	grpcCallOptions := []grpc.CallOption{
+		grpc.CallContentSubtype((&wrapMicroCodec{cf}).Name()),
+	}
+
+	if opts := g.getGrpcCallOptions(opts.Context); opts != nil {
+		grpcCallOptions = append(grpcCallOptions, opts...)
+	}
+
+	if opts.ResponseMetadata != nil {
+		gmd = gmetadata.MD{}
+		grpcCallOptions = append(grpcCallOptions, grpc.Header(&gmd))
+	}
 
 	go func() {
-		grpcCallOptions := []grpc.CallOption{
-			grpc.ForceCodec(&wrapMicroCodec{cf}),
-			grpc.CallContentSubtype((&wrapMicroCodec{cf}).Name()),
-		}
-		if opts := g.getGrpcCallOptions(); opts != nil {
-			grpcCallOptions = append(grpcCallOptions, opts...)
-		}
 		err := cc.Invoke(ctx, methodToGRPC(req.Service(), req.Endpoint()), req.Body(), rsp, grpcCallOptions...)
 		ch <- microError(err)
 	}()
@@ -147,6 +169,13 @@ func (g *grpcClient) call(ctx context.Context, addr string, req client.Request,
 		grr = errors.Timeout("go.micro.client", "%v", ctx.Err())
 	}
 
+	if opts.ResponseMetadata != nil {
+		*opts.ResponseMetadata = metadata.New(gmd.Len())
+		for k, v := range gmd {
+			opts.ResponseMetadata.Set(k, strings.Join(v, ","))
+		}
+	}
+
 	return grr
 }
 
@@ -168,7 +197,7 @@ func (g *grpcClient) stream(ctx context.Context, addr string, req client.Request
 		header["timeout"] = fmt.Sprintf("%dn", opts.StreamTimeout)
 	}
 	// set the content type for the request
-	header["x-content-type"] = req.ContentType()
+	header["content-type"] = req.ContentType()
 
 	md := gmetadata.New(header)
 	ctx = gmetadata.NewOutgoingContext(ctx, md)
@@ -191,6 +220,7 @@ func (g *grpcClient) stream(ctx context.Context, addr string, req client.Request
 
 	maxRecvMsgSize := g.maxRecvMsgSizeValue()
 	maxSendMsgSize := g.maxSendMsgSizeValue()
+	cfgService := g.serviceConfig()
 
 	grpcDialOptions := []grpc.DialOption{
 		g.secure(addr),
@@ -198,13 +228,22 @@ func (g *grpcClient) stream(ctx context.Context, addr string, req client.Request
 			grpc.MaxCallRecvMsgSize(maxRecvMsgSize),
 			grpc.MaxCallSendMsgSize(maxSendMsgSize),
 		),
+		grpc.WithDefaultServiceConfig(cfgService),
 	}
 
-	if opts := g.getGrpcDialOptions(); opts != nil {
+	if opts := g.getGrpcDialOptions(opts.Context); opts != nil {
 		grpcDialOptions = append(grpcDialOptions, opts...)
 	}
 
-	cc, err := g.pool.getConn(dialCtx, addr, grpcDialOptions...)
+	contextDialer := g.opts.ContextDialer
+	if opts.ContextDialer != nil {
+		contextDialer = opts.ContextDialer
+	}
+	if contextDialer != nil {
+		grpcDialOptions = append(grpcDialOptions, grpc.WithContextDialer(contextDialer))
+	}
+
+	cc, err := g.pool.Get(dialCtx, addr, grpcDialOptions...)
 	if err != nil {
 		return errors.InternalServerError("go.micro.client", fmt.Sprintf("Error sending request: %v", err))
 	}
@@ -216,12 +255,17 @@ func (g *grpcClient) stream(ctx context.Context, addr string, req client.Request
 	}
 
 	grpcCallOptions := []grpc.CallOption{
-		grpc.ForceCodec(wc),
+		// grpc.ForceCodec(wc),
 		grpc.CallContentSubtype(wc.Name()),
 	}
-	if opts := g.getGrpcCallOptions(); opts != nil {
+	if opts := g.getGrpcCallOptions(opts.Context); opts != nil {
 		grpcCallOptions = append(grpcCallOptions, opts...)
 	}
+	var gmd gmetadata.MD
+	if opts.ResponseMetadata != nil {
+		gmd = gmetadata.MD{}
+		grpcCallOptions = append(grpcCallOptions, grpc.Header(&gmd))
+	}
 
 	// create a new cancelling context
 	newCtx, cancel := context.WithCancel(ctx)
@@ -232,7 +276,7 @@ func (g *grpcClient) stream(ctx context.Context, addr string, req client.Request
 		// cancel the context
 		cancel()
 		// release the connection
-		g.pool.release(cc, err)
+		g.pool.Put(cc, err)
 		// now return the error
 		return errors.InternalServerError("go.micro.client", fmt.Sprintf("Error creating stream: %v", err))
 	}
@@ -260,13 +304,14 @@ func (g *grpcClient) stream(ctx context.Context, addr string, req client.Request
 			}
 
 			// defer execution of release
-			g.pool.release(cc, err)
+			g.pool.Put(cc, err)
 		},
 	}
 
 	// set the stream as the response
 	val := reflect.ValueOf(rsp).Elem()
 	val.Set(reflect.ValueOf(stream).Elem())
+
 	return nil
 }
 
@@ -328,6 +373,17 @@ func (g *grpcClient) newCodec(ct string) (codec.Codec, error) {
 	return nil, codec.ErrUnknownContentType
 }
 
+func (g *grpcClient) serviceConfig() string {
+	if g.opts.Context == nil {
+		return DefaultServiceConfig
+	}
+	v := g.opts.Context.Value(serviceConfigKey{})
+	if v == nil {
+		return DefaultServiceConfig
+	}
+	return v.(string)
+}
+
 func (g *grpcClient) Init(opts ...client.Option) error {
 	if len(opts) == 0 && g.init {
 		return nil
@@ -391,6 +447,7 @@ func (g *grpcClient) Call(ctx context.Context, req client.Request, rsp interface
 	}
 	// make a copy of call opts
 	callOpts := g.opts.CallOptions
+
 	for _, opt := range opts {
 		opt(&callOpts)
 	}
@@ -728,41 +785,45 @@ func (g *grpcClient) Name() string {
 	return g.opts.Name
 }
 
-func (g *grpcClient) getGrpcDialOptions() []grpc.DialOption {
+func (g *grpcClient) getGrpcDialOptions(ctx context.Context) []grpc.DialOption {
-	if g.opts.CallOptions.Context == nil {
+	var opts []grpc.DialOption
-		return nil
+
+	if g.opts.CallOptions.Context != nil {
+		if v := g.opts.CallOptions.Context.Value(grpcDialOptions{}); v != nil {
+			if vopts, ok := v.([]grpc.DialOption); ok {
+				opts = append(opts, vopts...)
+			}
+		}
 	}
 
-	v := g.opts.CallOptions.Context.Value(grpcDialOptions{})
+	if ctx != nil {
-
+		if v := ctx.Value(grpcDialOptions{}); v != nil {
-	if v == nil {
+			if vopts, ok := v.([]grpc.DialOption); ok {
-		return nil
+				opts = append(opts, vopts...)
-	}
+			}
-
+		}
-	opts, ok := v.([]grpc.DialOption)
-
-	if !ok {
-		return nil
 	}
 
 	return opts
 }
 
-func (g *grpcClient) getGrpcCallOptions() []grpc.CallOption {
+func (g *grpcClient) getGrpcCallOptions(ctx context.Context) []grpc.CallOption {
-	if g.opts.CallOptions.Context == nil {
+	var opts []grpc.CallOption
-		return nil
+
+	if g.opts.CallOptions.Context != nil {
+		if v := g.opts.CallOptions.Context.Value(grpcCallOptions{}); v != nil {
+			if vopts, ok := v.([]grpc.CallOption); ok {
+				opts = append(opts, vopts...)
+			}
+		}
 	}
 
-	v := g.opts.CallOptions.Context.Value(grpcCallOptions{})
+	if ctx != nil {
-
+		if v := ctx.Value(grpcCallOptions{}); v != nil {
-	if v == nil {
+			if vopts, ok := v.([]grpc.CallOption); ok {
-		return nil
+				opts = append(opts, vopts...)
-	}
+			}
-
+		}
-	opts, ok := v.([]grpc.CallOption)
-
-	if !ok {
-		return nil
 	}
 
 	return opts
@@ -771,14 +832,15 @@ func (g *grpcClient) getGrpcCallOptions() []grpc.CallOption {
 func NewClient(opts ...client.Option) client.Client {
 	options := client.NewOptions(opts...)
 	// default content type for grpc
-	options.ContentType = DefaultContentType
+	if options.ContentType == "" {
+		options.ContentType = DefaultContentType
+	}
 
 	rc := &grpcClient{
 		opts: options,
 	}
 
-	rc.pool = newPool(options.PoolSize, options.PoolTTL, rc.poolMaxIdle(), rc.poolMaxStreams())
+	rc.pool = NewConnPool(options.PoolSize, options.PoolTTL, rc.poolMaxIdle(), rc.poolMaxStreams())
-
 	c := client.Client(rc)
 
 	// wrap in reverse

grpc_pool.go

@@ -10,7 +10,7 @@ import (
 	"google.golang.org/grpc/connectivity"
 )
 
-type pool struct {
+type ConnPool struct {
 	conns      map[string]*streamsPool
 	size       int
 	ttl        int64
@@ -21,36 +21,36 @@ type pool struct {
 
 type streamsPool struct {
 	//  head of list
-	head *poolConn
+	head *PoolConn
 	//  busy conns list
-	busy *poolConn
+	busy *PoolConn
 	//  the siza of list
 	count int
 	//  idle conn
 	idle int
 }
 
-type poolConn struct {
+type PoolConn struct {
 	err error
 	*grpc.ClientConn
-	next    *poolConn
+	next    *PoolConn
-	pool    *pool
+	pool    *ConnPool
 	sp      *streamsPool
-	pre     *poolConn
+	pre     *PoolConn
 	addr    string
 	streams int
 	created int64
 	in      bool
 }
 
-func newPool(size int, ttl time.Duration, idle int, ms int) *pool {
+func NewConnPool(size int, ttl time.Duration, idle int, ms int) *ConnPool {
 	if ms <= 0 {
 		ms = 1
 	}
 	if idle < 0 {
 		idle = 0
 	}
-	return &pool{
+	return &ConnPool{
 		size:       size,
 		ttl:        int64(ttl.Seconds()),
 		maxStreams: ms,
@@ -59,7 +59,7 @@ func newPool(size int, ttl time.Duration, idle int, ms int) *pool {
 	}
 }
 
-func (p *pool) getConn(ctx context.Context, addr string, opts ...grpc.DialOption) (*poolConn, error) {
+func (p *ConnPool) Get(ctx context.Context, addr string, opts ...grpc.DialOption) (*PoolConn, error) {
 	if strings.HasPrefix(addr, "http") {
 		addr = addr[strings.Index(addr, ":")+3:]
 	}
@@ -67,7 +67,7 @@ func (p *pool) getConn(ctx context.Context, addr string, opts ...grpc.DialOption
 	p.Lock()
 	sp, ok := p.conns[addr]
 	if !ok {
-		sp = &streamsPool{head: &poolConn{}, busy: &poolConn{}, count: 0, idle: 0}
+		sp = &streamsPool{head: &PoolConn{}, busy: &PoolConn{}, count: 0, idle: 0}
 		p.conns[addr] = sp
 	}
 	//  while we have conns check streams and then return one
@@ -135,7 +135,7 @@ func (p *pool) getConn(ctx context.Context, addr string, opts ...grpc.DialOption
 	if err != nil {
 		return nil, err
 	}
-	conn = &poolConn{ClientConn: cc, err: nil, addr: addr, pool: p, sp: sp, streams: 1, created: time.Now().Unix(), pre: nil, next: nil, in: false}
+	conn = &PoolConn{ClientConn: cc, err: nil, addr: addr, pool: p, sp: sp, streams: 1, created: time.Now().Unix(), pre: nil, next: nil, in: false}
 
 	//  add conn to streams pool
 	p.Lock()
@@ -147,7 +147,7 @@ func (p *pool) getConn(ctx context.Context, addr string, opts ...grpc.DialOption
 	return conn, nil
 }
 
-func (p *pool) release(conn *poolConn, err error) {
+func (p *ConnPool) Put(conn *PoolConn, err error) {
 	p.Lock()
 	p, sp, created := conn.pool, conn.sp, conn.created
 	//  try to add conn
@@ -182,11 +182,11 @@ func (p *pool) release(conn *poolConn, err error) {
 	p.Unlock()
 }
 
-func (conn *poolConn) Close() {
+func (conn *PoolConn) Close() {
-	conn.pool.release(conn, conn.err)
+	conn.pool.Put(conn, conn.err)
 }
 
-func removeConn(conn *poolConn) {
+func removeConn(conn *PoolConn) {
 	if conn.pre != nil {
 		conn.pre.next = conn.next
 	}
@@ -199,7 +199,7 @@ func removeConn(conn *poolConn) {
 	conn.sp.count--
 }
 
-func addConnAfter(conn *poolConn, after *poolConn) {
+func addConnAfter(conn *PoolConn, after *PoolConn) {
 	conn.next = after.next
 	conn.pre = after
 	if after.next != nil {

options.go

@@ -10,7 +10,7 @@ import (
 )
 
 var (
-	// DefaultPoolMaxStreams maximum streams on a connectioin
+	// DefaultPoolMaxStreams maximum streams on a connection
 	// (20)
 	DefaultPoolMaxStreams = 20
 
@@ -25,6 +25,9 @@ var (
 	// DefaultMaxSendMsgSize maximum message that client can send
 	// (4 MB).
 	DefaultMaxSendMsgSize = 1024 * 1024 * 4
+
+	// DefaultServiceConfig enable load balancing
+	DefaultServiceConfig = `{"loadBalancingPolicy":"round_robin"}`
 )
 
 type poolMaxStreams struct{}
@@ -70,9 +73,7 @@ func Codec(contentType string, c encoding.Codec) client.Option {
 
 type maxRecvMsgSizeKey struct{}
 
-//
 // MaxRecvMsgSize set the maximum size of message that client can receive.
-//
 func MaxRecvMsgSize(s int) client.Option {
 	return func(o *client.Options) {
 		if o.Context == nil {
@@ -84,9 +85,7 @@ func MaxRecvMsgSize(s int) client.Option {
 
 type maxSendMsgSizeKey struct{}
 
-//
 // MaxSendMsgSize set the maximum size of message that client can send.
-//
 func MaxSendMsgSize(s int) client.Option {
 	return func(o *client.Options) {
 		if o.Context == nil {
@@ -98,9 +97,7 @@ func MaxSendMsgSize(s int) client.Option {
 
 type grpcDialOptions struct{}
 
-//
 // DialOptions to be used to configure gRPC dial options
-//
 func DialOptions(opts ...grpc.DialOption) client.CallOption {
 	return func(o *client.CallOptions) {
 		if o.Context == nil {
@@ -112,9 +109,7 @@ func DialOptions(opts ...grpc.DialOption) client.CallOption {
 
 type grpcCallOptions struct{}
 
-//
 // CallOptions to be used to configure gRPC call options
-//
 func CallOptions(opts ...grpc.CallOption) client.CallOption {
 	return func(o *client.CallOptions) {
 		if o.Context == nil {
@@ -123,3 +118,14 @@ func CallOptions(opts ...grpc.CallOption) client.CallOption {
 		o.Context = context.WithValue(o.Context, grpcCallOptions{}, opts)
 	}
 }
+
+type serviceConfigKey struct{}
+
+func ServiceConfig(str string) client.CallOption {
+	return func(options *client.CallOptions) {
+		if options.Context == nil {
+			options.Context = context.Background()
+		}
+		options.Context = context.WithValue(options.Context, serviceConfigKey{}, str)
+	}
+}

request.go

@@ -38,15 +38,12 @@ func methodToGRPC(service, method string) string {
 	return fmt.Sprintf("/%s.%s/%s", service, mParts[0], mParts[1])
 }
 
-func newGRPCRequest(service, method string, request interface{}, contentType string, reqOpts ...client.RequestOption) client.Request {
+func newGRPCRequest(service, method string, request interface{}, contentType string, opts ...client.RequestOption) client.Request {
-	var opts client.RequestOptions
+	options := client.NewRequestOptions(opts...)
-	for _, o := range reqOpts {
-		o(&opts)
-	}
 
 	// set the content-type specified
-	if len(opts.ContentType) > 0 {
+	if len(options.ContentType) > 0 {
-		contentType = opts.ContentType
+		contentType = options.ContentType
 	}
 
 	return &grpcRequest{
@@ -54,7 +51,7 @@ func newGRPCRequest(service, method string, request interface{}, contentType str
 		method:      method,
 		request:     request,
 		contentType: contentType,
-		opts:        opts,
+		opts:        options,
 	}
 }
 

response.go

@@ -9,7 +9,7 @@ import (
 )
 
 type response struct {
-	conn   *poolConn
+	conn   *PoolConn
 	stream grpc.ClientStream
 	codec  codec.Codec
 }
@@ -23,7 +23,7 @@ func (r *response) Codec() codec.Codec {
 func (r *response) Header() metadata.Metadata {
 	meta, err := r.stream.Header()
 	if err != nil {
-		return metadata.New(0)
+		return nil
 	}
 	md := metadata.New(len(meta))
 	for k, v := range meta {

stream.go

@@ -17,7 +17,7 @@ type grpcStream struct {
 	request  client.Request
 	response client.Response
 	close    func(err error)
-	conn     *poolConn
+	conn     *PoolConn
 	sync.RWMutex
 	closed bool
 }