gRPC 是谷歌开源的一套 RPC 协议框架, gRPC底层传输使用的是HTTP协议.

RPC主要做两件事: 数据编码+请求映射

gRPC数据编码默认使用的是Protobuf

定义protocol文件并生成

syntax = "proto3";

option go_package = "example/eg-grpc/hello";
option java_multiple_files = true;
option java_package = "io.grpc.example.hello";
option java_outer_classname = "HelloProto";

package hello;

service Greeter {
    rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// 定义请求参数
message HelloRequest {
    string name = 1;
}

//定义响应参数
message HelloReply {
    string message = 1;
}

protoc编译-命令行执行

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

gRPC server

package main

import (
    "context"
    "example/eg-grpc/hello"
    "log"
    "net"

    "google.golang.org/grpc"
    "google.golang.org/grpc/reflection"
)

const (
    port = ":50051"
)

type server struct {
    hello.UnimplementedGreeterServer
}

func (s *server) SayHello(ctx context.Context, in *hello.HelloRequest) (*hello.HelloReply, error) {
    log.Printf("Receiver: %v", in.GetName())
    return &hello.HelloReply{Message: "Hello" + in.GetName()}, nil
}

func main() {
    lis, err := net.Listen("tcp", port)
    if err != nil {
        log.Fatalf("failed to listen: %v", err)
    }
    s := grpc.NewServer()
    reflection.Register(s)
    hello.RegisterGreeterServer(s, &server{})
    log.Printf("serve listening at %v", lis.Addr())
    if err := s.Serve(lis); err != nil {
        log.Fatalf("failed to serve: %v", err)
    }
}

gRPC client

package main

import (
    "context"
    "example/eg-grpc/hello"
    "log"
    "os"
    "time"

    "google.golang.org/grpc"
)

const (
    address     = "127.0.0.1:50051"
    defaultName = "world"
)

func main() {
    // 设置grpc服务器地址
    conn, err := grpc.Dial(address, grpc.WithInsecure(), grpc.WithBlock())

    if err != nil {
        log.Fatalf("did not connect: %v", err)
    }
    defer conn.Close()
    c := hello.NewGreeterClient(conn)

    name := defaultName
    if len(os.Args) > 1 {
        name = os.Args[1]
    }
    ctx, cancel := context.WithTimeout(context.Background(), time.Second)
    defer cancel()
    r, err := c.SayHello(ctx, &hello.HelloRequest{Name: name})
    if err != nil {
        log.Fatalf("could not greet: %v", err)
    }
    log.Printf("Greeting: %s", r.GetMessage())
}

安装gRPC调试工具

go install github.com/fullstorydev/grpcui/cmd/grpcui

启动gRPC服务并启动调试工具

启动grpc服务: go run server/cmd/main.go

启动grpcui调试服务: grpcui -plaintext 127.0.0.1:50051

相关资料

grpc

官方-examples

golang-api-docs

调试工具-grpcurl

调试工具-grpcui