Lesson 2.6: gRPC 入门

学习目标

• 理解 gRPC 的通信模型
• 掌握 Protocol Buffers 的定义

---

1. Protocol Buffers

syntax = "proto3";

package user;

option go_package = "./pb;pb";

service UserService {
    rpc GetUser (GetUserRequest) returns (User);
    rpc ListUsers (ListUsersRequest) returns (ListUsersResponse);
    rpc CreateUser (CreateUserRequest) returns (User);
}

message User {
    string id = 1;
    string name = 2;
    string email = 3;
    int32 age = 4;
}

message GetUserRequest {
    string id = 1;
}

# 生成 Go 代码
protoc --go_out=. --go-grpc_out=. user.proto

2. 服务端实现

type userServer struct {
    pb.UnimplementedUserServiceServer
}

func (s *userServer) GetUser(ctx context.Context, req *pb.GetUserRequest) (*pb.User, error) {
    // 业务逻辑
    return &pb.User{
        Id:    req.Id,
        Name:  "Alice",
        Email: "alice@example.com",
    }, nil
}

func main() {
    lis, _ := net.Listen("tcp", ":50051")
    s := grpc.NewServer()
    pb.RegisterUserServiceServer(s, &userServer{})
    s.Serve(lis)
}

3. 客户端调用

func main() {
    conn, _ := grpc.Dial("localhost:50051", grpc.WithTransportCredentials(insecure.NewCredentials()))
    defer conn.Close()

    client := pb.NewUserServiceClient(conn)
    user, _ := client.GetUser(context.Background(), &pb.GetUserRequest{Id: "1"})
    fmt.Printf("User: %+v\n", user)
}

推荐阅读

• grpc-in-go
• grpc-protobuf-guide