grpc 入门应用

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go install github.com/golang/protobuf/protoc-gen-go@v1.4.0
go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.1

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--go_out: protoc-gen-go: plugins are not supported; use 'protoc --go-grpc_out=...' to generate gRPC

See https://grpc.io/docs/languages/go/quickstart/#regenerate-grpc-code for more information.

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syntax = "proto3"; // 使用protobuf版本3

option go_package = "./protobuf"; // 这个影响生成的目录及go的package命名

// 定义一个计算服务, 输入为CalcRequest, 输出为CalcResponse
service CalculatorService {
  rpc calc(CalcRequest) returns (CalcResponse) {};
}

// 计算两个数某种运算(如加法)的参数
message CalcRequest {
  double a = 1;
  double b = 2;
  string op = 3;
}

// 计算结果
message CalcResponse {
  double r = 1;
}

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protoc  --go_out=plugins=grpc:. calculator.proto

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package main

import (
	"context"
	"fmt"
	"net"

	"go.src/grpc/calculator/protobuf"
	"google.golang.org/grpc"
)

// 实现: CalculatorServiceServer接口, 在calculator.pb.go中定义
type server struct{}

func (s server) Calc(ctx context.Context, req *protobuf.CalcRequest) (resp *protobuf.CalcResponse, err error) {
	a := req.GetA()
	b := req.GetB()
	op := req.GetOp()
	resp = &protobuf.CalcResponse{}

	switch op {
	case "+":
		resp.R = a + b
	case "-":
		resp.R = a - b
	case "*":
		resp.R = a * b
	case "/":
		if b == 0 {
			err = fmt.Errorf("divided by zero")
			return
		}
		resp.R = a / b
	}
	return
}

// 启动rpc server
func main() {
	listener, err := net.Listen("tcp", "localhost:3233")
	if err != nil {
		panic(err)
	}

	s := grpc.NewServer()
	protobuf.RegisterCalculatorServiceServer(s, &server{})
	fmt.Println("server start")
	err = s.Serve(listener)
	if err != nil {
		panic(err)
	}
}

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package main

import (
	"context"
	"fmt"
	"log"

	"go.src/grpc/calculator/protobuf"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
)

func main() {
	// 连上grpc server
	//conn, err := grpc.Dial("localhost:3233", grpc.WithInsecure())
	conn, err := grpc.Dial("localhost:3233", grpc.WithTransportCredentials(insecure.NewCredentials()))
	if err != nil {
		log.Fatalf("did not connect: %v", err)
	}

	defer conn.Close()

	c := protobuf.NewCalculatorServiceClient(conn)

	// 调用远程方法
	resp, err := c.Calc(context.Background(), &protobuf.CalcRequest{
		A:  1,
		B:  2,
		Op: "+",
	})
	if err != nil {
		fmt.Println("calc err: ", err.Error())
		return
	}
	fmt.Println("calc success,respR: ", resp.GetR()) // 3
}