环境

安装

• protoc

下载对应版本的安装包https://github.com/protocolbuffers/protobuf/releases

解压后随便找个地方放，把bin目录地址加到环境变量中。

>protoc –version
libprotoc 3.12.0

• micro和protoc相关的go插件

#设置mod模式和代理
go env -w GO111MODULE=on
go env -w GOPROXY=https://goproxy.cn,https://proxy.golang.org,direct

#安装
go get -u -v github.com/golang/protobuf/protoc-gen-go 
go get -u -v google.golang.org/grpc
#这里若加-u选项貌似会报错，就不加了
go get -v github.com/micro/micro/v2
go get -u -v github.com/micro/go-micro/v2
go get -v github.com/micro/micro/v2/cmd/protoc-gen-micro@master

顺利安装完毕后，在$GOPATH/bin下应该会有这仨执行文件

• consul（可选）

因为micro v2版本官方弃用consul，默认改用了mdns，生产推荐etcd。参考go-micro v2弃用了consul作为默认的服务发现

所以装不装这个都可以。

https://www.consul.io/downloads.html下载对应版本，网速限制的话可以在这里https://download.csdn.net/download/HJXINKKL/12428749下

解压后添加路径到环境变量

>consul -v
Consul v1.7.3

开始创建

• 目录结构

 │  go.mod │  go.sum │ └─helloworld     ├─message     │      greeter.pb.go     │      greeter.pb.micro.go     │      greeter.proto     │     └─services             client.go             server.go

• 初始化项目

在$GOPATH/src下

mkdir microTest
go mod init microTest

• 定义API 

创建helloworld/message/greeter.proto

 syntax = "proto3";  package microTest; option go_package = "helloworld/message";  service Greeter {     rpc Hello (Request) returns (Response) {     } }  message Request {     string name = 1; }  message Response {     string greeting = 2; }

microTest下执行protoc命令，就会在helloworld/message/自动生成greeter.pb.go、greeter.pb.micro.go

protoc –micro_out=. –go_out=. helloworld/message/greeter.proto

• 创建service

创建helloworld/services/server.go文件

 package main  import (     "context"     "fmt"      micro "github.com/micro/go-micro/v2"     proto "microTest/helloworld/message" )  type Greeter struct{}  func (g *Greeter) Hello(ctx context.Context, req *proto.Request, rsp *proto.Response) 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"),     )      // Init will parse the command line flags.     service.Init()      // Register handler     proto.RegisterGreeterHandler(service.Server(), new(Greeter))      // Run the server     if err := service.Run(); err != nil {         fmt.Println(err)     } } 

• 创建client

创建helloworld/services/client.go文件

 package main  import (     "context"     "fmt"      micro "github.com/micro/go-micro/v2"     proto "microTest/helloworld/message" )  func main() {     // Create a new service     service := micro.NewService(micro.Name("greeter.client"))     // Initialise the client and parse command line flags     service.Init()      // Create new greeter client     greeter := proto.NewGreeterService("greeter", service.Client())      // Call the greeter     rsp, err := greeter.Hello(context.TODO(), &proto.Request{Name: "John"})     if err != nil {         fmt.Println(err)     }      // Print response     fmt.Println(rsp.Greeting) } 

运行服务

• 启动server

go run helloworld/services/server.go

• client请求

go run helloworld/services/client.go

此时，有可能会报错

 {"id":"go.micro.client","code":408,"detail":"context deadline exceeded","status":"Request Timeout"} panic: runtime error: invalid memory address or nil pointer dereference [signal 0xc0000005 code=0x0 addr=0x28 pc=0xeef454]

• 定位报错原因

查看服务列表，greeter服务已经启动了

> micro list services
greeter

查看指定服务信息

micro get service greeter

 service  greeter  version latest  ID      Address Metadata greeter-28a0d7a1-4a26-499d-bd9f-364151021f50    10.0.0.1:57647  broker=http,protocol=grpc,registry=mdns,server=grpc,transport=grpc  Endpoint: Greeter.Hello  Request: {         message_state MessageState {                 no_unkeyed_literals NoUnkeyedLiterals                 do_not_compare DoNotCompare                 do_not_copy DoNotCopy                 message_info MessageInfo         }         int32 int32         unknown_fields []uint8         name string }  Response: {         message_state MessageState {                 no_unkeyed_literals NoUnkeyedLiterals                 do_not_compare DoNotCompare                 do_not_copy DoNotCopy                 message_info MessageInfo         }         int32 int32         unknown_fields []uint8         greeting string }

注意到Address地址为10.0.0.1:57647，也就是micro注册到默认网段去了，所以导致服务不可达。

• 带指定server_address参数启动server

go run helloworld/services/server.go –server_address=localhost:8888

• 再次client请求

go run helloworld/services/client.go

这次返回正常结果

 Hello John

•  再次查看指定服务信息

micro get service greeter

 ID      Address Metadata greeter-f875a030-436a-420d-a29a-a66249d22381    127.0.0.1:8888  protocol=grpc,registry=mdns,server=grpc,transport=grpc,broker=http

•  服务调用

仿照官网给出的例子

micro call greeter Greeter.Hello ‘{“name”: “John”}’ 

不管是PowerShell还是CMD都会报 invalid character 的错误。

需要将”进行转义”，才可以正常执行，注意PowerShell和CMD的不同

使用consul做服务发现

如果非要使用consul的话，就得往client.go和server.go的import中添加

 _ "github.com/micro/go-plugins/registry/consul/v2"

•  启动Consul agent的开发模式

consul agent -dev

• 启动server

go run helloworld/services/server.go –registry=consul –server_address=localhost:8888

• client请求

go run helloworld/services/client.go –registry=consul