gRPC的Golang编译及简单使用

1. 前置条件

Go
Protocol buffer编译器：protoc，安装可参考Protocol buffer编译安装

Go 协议编译插件

下载并安装编译插件，这里确保已配置代理可以下载。

$ export GO111MODULE=on  # Enable module mode
$ go get google.golang.org/protobuf/cmd/protoc-gen-go \
        google.golang.org/grpc/cmd/protoc-gen-go-grpc
#在所在项目中，执行以下命令可指定版本
#go get github.com/golang/protobuf/protoc-gen-go@v1.0.0

$ export GO111MODULE=on # Enable module mode

$ go get google.golang.org/protobuf/cmd/protoc-gen-go \

google.golang.org/grpc/cmd/protoc-gen-go-grpc

#在所在项目中，执行以下命令可指定版本

#go get github.com/golang/protobuf/protoc-gen-go@v1.0.0

添加路径到环境变量，使得protoc编译其可找到go编译插件

$ export PATH="$PATH:$(go env GOPATH)/bin"

1

$ export PATH="$PATH:$(go env GOPATH)/bin"

2. 获取示范代码

代码资源是grpc-go部分代码

```bash
#下载代码或直接下载压缩包
git clone -b v1.35.0 https://github.com/grpc/grpc-go
cd grpc-go/examples/helloworld
```

```bash

#下载代码或直接下载压缩包

git clone -b v1.35.0 https://github.com/grpc/grpc-go

cd grpc-go/examples/helloworld

```

3. 运行示范代码

服务端

进入目录examples/helloworld，编译并执行服务端代码

$ go run greeter_server/main.go

# server代码
package main

import (
    "context"
    "flag"
    "fmt"
    "log"
    "net"

    "google.golang.org/grpc"
    pb "google.golang.org/grpc/examples/helloworld/helloworld"
)

var (
    port = flag.Int("port", 50051, "The server port")
)

// server is used to implement helloworld.GreeterServer.
type server struct {
    pb.UnimplementedGreeterServer
}

// SayHello implements helloworld.GreeterServer
func (s *server) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {
    log.Printf("Received: %v", in.GetName())
    return &pb.HelloReply{Message: "Hello " + in.GetName()}, nil
}

func main() {
    flag.Parse()
    lis, err := net.Listen("tcp", fmt.Sprintf("localhost:%d", *port))
    if err != nil {
        log.Fatalf("failed to listen: %v", err)
    }
    s := grpc.NewServer()
    pb.RegisterGreeterServer(s, &server{})
    log.Printf("server listening at %v", lis.Addr())
    if err := s.Serve(lis); err != nil {
        log.Fatalf("failed to serve: %v", err)
    }
}

$ go run greeter_server/main.go

# server代码

package main

import (

"context"

"flag"

"fmt"

"log"

"net"

"google.golang.org/grpc"

pb "google.golang.org/grpc/examples/helloworld/helloworld"

)

var (

port = flag.Int("port", 50051, "The server port")

)

// server is used to implement helloworld.GreeterServer.

type server struct {

pb.UnimplementedGreeterServer

}

// SayHello implements helloworld.GreeterServer

func (s *server) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {

log.Printf("Received: %v", in.GetName())

return &pb.HelloReply{Message: "Hello " + in.GetName()}, nil

}

func main() {

flag.Parse()

lis, err := net.Listen("tcp", fmt.Sprintf("localhost:%d", *port))

if err != nil {

log.Fatalf("failed to listen: %v", err)

}

s := grpc.NewServer()

pb.RegisterGreeterServer(s, &server{})

log.Printf("server listening at %v", lis.Addr())

if err := s.Serve(lis); err != nil {

log.Fatalf("failed to serve: %v", err)

}

客户端

在另一个终端中，编译并执行客户端代码，查看客户输出：

$ go run greeter_client/main.go
Greeting: Hello world

#Client 代码
package main

import (
    "context"
    "flag"
    "log"
    "time"

    "google.golang.org/grpc"
    pb "google.golang.org/grpc/examples/helloworld/helloworld"
)

const (
    defaultName = "world"
)

var (
    addr = flag.String("addr", "localhost:50051", "the address to connect to")
    name = flag.String("name", defaultName, "Name to greet")
)

func main() {
    flag.Parse()
    // Set up a connection to the server.
    conn, err := grpc.Dial(*addr, grpc.WithInsecure())
    if err != nil {
        log.Fatalf("did not connect: %v", err)
    }
    defer conn.Close()
    c := pb.NewGreeterClient(conn)

    // Contact the server and print out its response.
    ctx, cancel := context.WithTimeout(context.Background(), time.Second)
    defer cancel()
    r, err := c.SayHello(ctx, &pb.HelloRequest{Name: *name})
    if err != nil {
        log.Fatalf("could not greet: %v", err)
    }
    log.Printf("Greeting: %s", r.GetMessage())
}

$ go run greeter_client/main.go

Greeting: Hello world

#Client 代码

package main

import (

"context"

"flag"

"log"

"time"

"google.golang.org/grpc"

pb "google.golang.org/grpc/examples/helloworld/helloworld"

)

const (

defaultName = "world"

)

var (

addr = flag.String("addr", "localhost:50051", "the address to connect to")

name = flag.String("name", defaultName, "Name to greet")

)

func main() {

flag.Parse()

// Set up a connection to the server.

conn, err := grpc.Dial(*addr, grpc.WithInsecure())

if err != nil {

log.Fatalf("did not connect: %v", err)

}

defer conn.Close()

c := pb.NewGreeterClient(conn)

// Contact the server and print out its response.

ctx, cancel := context.WithTimeout(context.Background(), time.Second)

defer cancel()

r, err := c.SayHello(ctx, &pb.HelloRequest{Name: *name})

if err != nil {

log.Fatalf("could not greet: %v", err)

}

log.Printf("Greeting: %s", r.GetMessage())

}

protobuffer接口

#helloworld.proto文件

syntax = "proto3";

option go_package = "google.golang.org/grpc/examples/helloworld/helloworld";
option java_multiple_files = true;
option java_package = "io.grpc.examples.helloworld";
option java_outer_classname = "HelloWorldProto";

package helloworld;

// The greeting service definition.
service Greeter {
  // Sends a greeting
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string message = 1;
}

#helloworld.proto文件

syntax = "proto3";

option go_package = "google.golang.org/grpc/examples/helloworld/helloworld";

option java_multiple_files = true;

option java_package = "io.grpc.examples.helloworld";

option java_outer_classname = "HelloWorldProto";

package helloworld;

// The greeting service definition.

service Greeter {

// Sends a greeting

rpc SayHello (HelloRequest) returns (HelloReply) {}

}

// The request message containing the user's name.

message HelloRequest {

string name = 1;

}

// The response message containing the greetings

message HelloReply {

string message = 1;

}

4. 升级gRPC服务

5. 重生成gRPC代码

在使用新服务前，需要重编译已经修改的.proto文件；
这里还是在目录examples/helloworld中，运行如下命令：

$ protoc --go_out=. --go_opt=paths=source_relative \
    --go-grpc_out=. --go-grpc_opt=paths=source_relative \
    helloworld/helloworld.proto

$ protoc --go_out=. --go_opt=paths=source_relative \

--go-grpc_out=. --go-grpc_opt=paths=source_relative \

helloworld/helloworld.proto

这样重生产了代码helloworld/helloworld.pb.go和helloworld/helloworld_grpc.pb.go,包含如下：

填充、序列化、和检索的HelloRequest和HelloReply 类型；
生成客户端和服务端代码.

5.1. 生成protobuf代码

不需要生成xxx_grpc.pb.go文件执行如下命令

$ protoc -I "${GOBGP}"/api --go_out=plugins=grpc:${GOBGP}/api "${GOBGP}"/api/capability.proto "${GOBGP}"/api/attribute.proto

1	$ protoc -I "${GOBGP}"/api --go_out=plugins=grpc:${GOBGP}/api "${GOBGP}"/api/capability.proto "${GOBGP}"/api/attribute.proto

5.2. 生成包含grpc的protobuf代码

如果需要生成grpc.go文件执行如下命令，${GOBGP}为某一项目路径；--go-grpc_out表示XX_rpc需要生成路径；

# service Greeter {
#   // Sends a greeting
#   rpc SayHello (HelloRequest) returns (HelloReply) {}
# }

#第一种方式(建议)：
protoc -I "${GOBGP}"/api --go_out=plugins=grpc:${GOBGP}/api "${GOBGP}"/api/*.proto

#第二种方式: 需要额外二进制文件protoc-gen-go-grpc，位于项目github.com/golang/protobuf中目录protoc-gen-go
$ protoc -I "${GOBGP}"/api --go_out=${GOBGP}/api --go-grpc_out=${GOBGP}/api "${GOBGP}"/api/gobgp.proto

# service Greeter {

# // Sends a greeting

# rpc SayHello (HelloRequest) returns (HelloReply) {}

# }

#第一种方式(建议)：

protoc -I "${GOBGP}"/api --go_out=plugins=grpc:${GOBGP}/api "${GOBGP}"/api/*.proto

#第二种方式: 需要额外二进制文件protoc-gen-go-grpc，位于项目github.com/golang/protobuf中目录protoc-gen-go

$ protoc -I "${GOBGP}"/api --go_out=${GOBGP}/api --go-grpc_out=${GOBGP}/api "${GOBGP}"/api/gobgp.proto

6. 警告缺少go_package

警告WARNING: Missing 'go_package' option in "gobgp.proto"please specify it with the full Go package path as
a future release of protoc-gen-go will require this be specified。

每个*.proto添加option go_package = "./;gobgpapi";

在syntax下面添加option信息
option go_package = "aaa;bbb";
aaa 表示生成的go文件的存放地址，会自动生成目录的。
bbb 表示生成的go文件所属的包名

7. undefined: grpc.SupportPackageIsVersion6 grpc.ClientConnInterface 问题解决

问题原因
由于protoc的 go语言插件protoc-gen-go与google.golang.org/grpc版本不兼容所致,
因为grpc(google.golang.org/grpc)降了到了v1.36.1，高版本protoc-gen-go编译出来的your-module.pb.go不兼容低版本的grpc,所以protoc-gen-go也要相应降级。这里安装版本如下，

github.com/golang/protobuf v1.0.0 protoc-gen-go v1.23.0; protoc 建议版本 v3.7.1 ，否则编译protobuf不支持格式；

1
2
3

    github.com/golang/protobuf v1.0.0
    protoc-gen-go v1.23.0;
    protoc  建议版本 v3.7.1 ，否则编译protobuf不支持格式；
方法一：下载指定版本库的具体步骤
1. 先删除当前项目中的vendor目录: rm -rf vendor 或手动删除;
2. 再替换go.mod中依赖库版本:
  go mod edit -require="github.com/golang/protobuf@v1.0.0"
  go mod edit -require="google.golang.org/grpc@v1.5.1"
3. 下载指定版本v1.26.0: go get -u -x google.golang.org/grpc@v1.5.1
  go get -u -x github.com/golang/protobuf@v1.0.0
4. 然后再go mod vendor
5. 再运行程:go build main.go
方法二
参考该片文章undefined: proto.ProtoPackageIsVersion3

参考文章Golang gRPC Quickstart

赞赏

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1. 前置条件

2. 获取示范代码

3. 运行示范代码

4. 升级gRPC服务

5. 重生成gRPC代码

5.1. 生成protobuf代码

5.2. 生成包含grpc的protobuf代码

6. 警告缺少go_package

7. undefined: grpc.SupportPackageIsVersion6 grpc.ClientConnInterface 问题解决

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