182 lines
5.5 KiB
Markdown
182 lines
5.5 KiB
Markdown
# Go Micro [](https://godoc.org/github.com/micro/go-micro) [](https://travis-ci.org/micro/go-micro)
|
|
|
|
Go Micro is a pluggable RPC based microservice library which provides the fundamental building blocks for writing distributed applications. It is part of the [Micro](https://github.com/micro/micro) toolchain. It supports Proto-RPC and JSON-RPC as the request/response protocol out of the box and defaults to Consul for discovery.
|
|
|
|
Every aspect of go-micro is pluggable.
|
|
|
|
An example server can be found in examples/server.
|
|
|
|
- [Mailing List](https://groups.google.com/forum/#!forum/micro-services)
|
|
- [Slack](https://micro-services.slack.com) : [auto-invite](http://micro-invites.herokuapp.com/)
|
|
|
|
## Features
|
|
|
|
Feature | Package | Built-in Plugin | Description
|
|
------- | ------- | --------- | -----------
|
|
Discovery | [Registry](https://godoc.org/github.com/micro/go-micro/registry) | consul | A way of locating services to communicate with
|
|
Client | [Client](https://godoc.org/github.com/micro/go-micro/client) | rpc | Used to make RPC requests to a service
|
|
Codec | [Codec](https://godoc.org/github.com/micro/go-micro/codec) | proto,json | Encoding/Decoding handler for requests
|
|
Balancer | [Selector](https://godoc.org/github.com/micro/go-micro/selector) | random | Service node filter and pool
|
|
Server | [Server](https://godoc.org/github.com/micro/go-micro/server) | rpc | Listens and serves RPC requests
|
|
Pub/Sub | [Broker](https://godoc.org/github.com/micro/go-micro/broker) | http | Publish and Subscribe to events
|
|
Transport | [Transport](https://godoc.org/github.com/micro/go-micro/transport) | http | Communication mechanism between services
|
|
|
|
## Go Plugins
|
|
|
|
By default go-micro only provides a single implementation of each interface. Plugins can be found at [github.com/micro/go-plugins](https://github.com/micro/go-plugins). Contributions welcome!
|
|
|
|
## Prerequisites
|
|
|
|
Consul is the default discovery mechanism provided in go-micro. Discovery is however pluggable so you can used etcd, kubernetes, zookeeper, etc.
|
|
|
|
### Install Consul
|
|
[https://www.consul.io/intro/getting-started/install.html](https://www.consul.io/intro/getting-started/install.html)
|
|
|
|
## Getting Started
|
|
|
|
### Run Consul
|
|
```
|
|
$ consul agent -server -bootstrap-expect 1 -data-dir /tmp/consul
|
|
```
|
|
|
|
### Run Service
|
|
```
|
|
$ go run examples/service/main.go --logtostderr
|
|
I0102 00:22:26.413467 12018 rpc_server.go:297] Listening on [::]:62492
|
|
I0102 00:22:26.413803 12018 http_broker.go:115] Broker Listening on [::]:62493
|
|
I0102 00:22:26.414009 12018 rpc_server.go:212] Registering node: greeter-e6b2fc6f-b0e6-11e5-a42f-68a86d0d36b6
|
|
```
|
|
|
|
### Test Service
|
|
```
|
|
$ go run examples/service/main.go --client
|
|
Hello John
|
|
```
|
|
|
|
## Writing a service
|
|
|
|
### Create request/response proto
|
|
`go-micro/examples/service/proto/greeter.proto`:
|
|
|
|
```proto
|
|
syntax = "proto3";
|
|
|
|
service Greeter {
|
|
rpc Hello(HelloRequest) returns (HelloResponse) {}
|
|
}
|
|
|
|
message HelloRequest {
|
|
string name = 1;
|
|
}
|
|
|
|
message HelloResponse {
|
|
string greeting = 2;
|
|
}
|
|
```
|
|
|
|
### Install protobuf for code generation
|
|
|
|
We use a protobuf plugin for code generation. This is completely optional. Look at [examples/server](https://github.com/micro/go-micro/blob/master/examples/server/main.go)
|
|
and [examples/client](https://github.com/micro/go-micro/blob/master/examples/client/main.go) for examples without code generation.
|
|
|
|
```shell
|
|
go get github.com/micro/protobuf
|
|
```
|
|
|
|
Compile proto `protoc -I$GOPATH/src --go_out=plugins=micro:$GOPATH/src $GOPATH/src/github.com/micro/go-micro/examples/service/proto/greeter.proto`
|
|
|
|
### Define the service
|
|
`go-micro/examples/service/main.go`:
|
|
|
|
```go
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
|
|
micro "github.com/micro/go-micro"
|
|
proto "github.com/micro/go-micro/examples/service/proto"
|
|
"golang.org/x/net/context"
|
|
)
|
|
|
|
type Greeter struct{}
|
|
|
|
func (g *Greeter) Hello(ctx context.Context, req *proto.HelloRequest, rsp *proto.HelloResponse) error {
|
|
rsp.Greeting = "Hello " + req.Name
|
|
return nil
|
|
}
|
|
|
|
func main() {
|
|
// Create a new service. Optionally include some options here.
|
|
service := micro.NewService(
|
|
micro.Name("greeter"),
|
|
micro.Version("latest"),
|
|
micro.Metadata(map[string]string{
|
|
"type": "helloworld",
|
|
}),
|
|
)
|
|
|
|
// Init will parse the command line flags. Any flags set will
|
|
// override the above settings. Options defined here will
|
|
// override anything set on the command line.
|
|
service.Init()
|
|
|
|
// Register handler
|
|
proto.RegisterGreeterHandler(service.Server(), new(Greeter))
|
|
|
|
// Run the server
|
|
if err := service.Run(); err != nil {
|
|
fmt.Println(err)
|
|
}
|
|
}
|
|
```
|
|
|
|
### Run service
|
|
```
|
|
go run examples/service/main.go --logtostderr
|
|
I0102 00:22:26.413467 12018 rpc_server.go:297] Listening on [::]:62492
|
|
I0102 00:22:26.413803 12018 http_broker.go:115] Broker Listening on [::]:62493
|
|
I0102 00:22:26.414009 12018 rpc_server.go:212] Registering node: greeter-e6b2fc6f-b0e6-11e5-a42f-68a86d0d36b6
|
|
```
|
|
|
|
### Define a client
|
|
|
|
`client.go`
|
|
|
|
```go
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
|
|
micro "github.com/micro/go-micro"
|
|
proto "github.com/micro/go-micro/examples/service/proto"
|
|
"golang.org/x/net/context"
|
|
)
|
|
|
|
|
|
func main() {
|
|
// Create a new service. Optionally include some options here.
|
|
service := micro.NewService(micro.Name("greeter.client"))
|
|
|
|
// Create new greeter client
|
|
greeter := proto.NewGreeterClient("greeter", service.Client())
|
|
|
|
// Call the greeter
|
|
rsp, err := greeter.Hello(context.TODO(), &proto.HelloRequest{Name: "John"})
|
|
if err != nil {
|
|
fmt.Println(err)
|
|
}
|
|
|
|
// Print response
|
|
fmt.Println(rsp.Greeting)
|
|
}
|
|
```
|
|
|
|
### Run the client
|
|
|
|
```shell
|
|
go run client.go
|
|
Hello John
|
|
```
|