【Golang】Golang 使用 gRPC

2020-01-12

定义 gRPC的.proto

syntax = "proto3";

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;
}

Generate gRPC code

Next we need to update the gRPC code used by our application to use the new service definition. From the same examples dir as above ($GOPATH/src/google.golang.org/grpc/examples/helloworld)

1	$ protoc -I helloworld/ helloworld/helloworld.proto --go_out=plugins=grpc:helloworld

一个官方的 Demo

client.go

// Package main implements a client for Greeter service.
package main

import (
	"context"
	//pb "google.golang.org/grpc/examples/helloworld/helloworld"
	"log"
	"os"
	"time"

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

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

func main() {
	// Set up a connection to the server.
	conn, err := grpc.Dial(address, grpc.WithInsecure(), grpc.WithBlock())
	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.
	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, &pb.HelloRequest{Name: name})
	if err != nil {
		log.Fatalf("could not greet: %v", err)
	}
	log.Printf("Greeting: %s", r.GetMessage())
}

server.go

//go:generate protoc -I ../helloworld --go_out=plugins=grpc:../helloworld ../helloworld/helloworld.proto

// Package main implements a server for Greeter service.
package main

import (
	"context"
	//pb "google.golang.org/grpc/examples/helloworld/helloworld"
	"log"
	"net"

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

const (
	port = ":50051"
)

// 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() {
	lis, err := net.Listen("tcp", port)
	if err != nil {
		log.Fatalf("failed to listen: %v", err)
	}
	s := grpc.NewServer()
	pb.RegisterGreeterServer(s, &server{})
	if err := s.Serve(lis); err != nil {
		log.Fatalf("failed to serve: %v", err)
	}
}

api.go

syntax = "proto3";

option java_multiple_files = true;
option java_package = "io.grpc.examples.helloworld";
option java_outer_classname = "HelloWorldProto";

package protobufsw;

// 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;
}

执行 protoc -I protobufsw/ protobufsw/api.proto --go_out=plugins=grpc:protobufsw 以将 api.go 生成 api.pb.go。此后，就可以运行 server.go 和 client.go

Reference

https://grpc.io/docs/quickstart/go/