grpc

• grpc
• grpc-go

gRPC seamlessly integrates Protobuf.

protobuf

• For those accustomed to JSON and XML data storage formats, I believe most of you haven't heard of Protocol Buffer.
• Protocol Buffer is actually a lightweight & efficient structured data storage format developed by Google, and its performance is truly much stronger than JSON and XML!
• Protobuf has gone through protobuf2 and protobuf3, with pb3 being significantly simplified compared to pb2. The current mainstream version is pb3.

Downloading protoc

Download protoc andgo get github.com/golang/protobuf/protoc-gen-go

syntax = "proto3";

option go_package = "."; //这名不写现在编译不了

message HelloRequest {
  string name = 1; //1 是编号不是值
}

protoc --proto_path=. \
  --go_out=. \
  --go-grpc_out=. \
  ./helloworld.proto

This will generate ahelloworld.pb.gofile in the directory.

Comparison of compression ratios

package main

import (
 "RpcLearn/protobuf"
 "encoding/json"
 "fmt"
 "github.com/golang/protobuf/proto"
)

// TIP <p>To run your code, right-click the code and select <b>Run</b>.</p> <p>Alternatively, click
// the <icon src="AllIcons.Actions.Execute"/> icon in the gutter and select the <b>Run</b> menu item from here.</p>
type Hello struct {
 Name string `json:"name"`
}

func main() {
 //TIP <p>Press <shortcut actionId="ShowIntentionActions"/> when your caret is at the underlined text
 // to see how GoLand suggests fixing the warning.</p><p>Alternatively, if available, click the lightbulb to view possible fixes.</p>
 //s := "gopher"
 //fmt.Printf("Hello and welcome, %s!\n", s)
 //
 //for i := 1; i <= 5; i++ {
 // //TIP <p>To start your debugging session, right-click your code in the editor and select the Debug option.</p> <p>We have set one <icon src="AllIcons.Debugger.Db_set_breakpoint"/> breakpoint
 // // for you, but you can always add more by pressing <shortcut actionId="ToggleLineBreakpoint"/>.</p>
 // fmt.Println("i =", 100/i)
 //}
 jsonStruct := Hello{
  Name: "gopher",
 }
 jsonReq, _ := json.Marshal(jsonStruct)
 fmt.Println(string(jsonReq))
 fmt.Println(len(jsonReq))
 req := __.HelloRequest{
  Name: "gopher",
 }
 rsp, _ := proto.Marshal(&req)
 fmt.Println(rsp)
 fmt.Println(len(rsp))

}

Approximately a twofold difference.

Explanation of Changes in Using Protobuf with Go Language

📌 Current Behavior Explanation

Starting from Go's Protobuf plugin v1.20+, gRPC support has been split into a separate plugin, protoc-gen-go-grpc, used to generate service interface-related code. This approach is more modular and has clearer responsibilities.

Therefore, execute the following command:

protoc --proto_path=. \
  --go_out=. \
  --go-grpc_out=. \
  ./your_file.proto

This will generate:

• your_file.pb.go: Contains message structures (e.g., Request, Response)
• your_file_grpc.pb.go: Contains service interface definitions (e.g., YourServiceServer)

It is recommended to retain and synchronize these two files.

Briefly Outline the gRPC Startup Process

1. Create stub files and method definitions, then compile.

// proto/helloworld.proto
syntax = "proto3";
option go_package = ".;proto";

service Greeter{
    rpc SayHello (HelloRequest) returns (HelloReply);
}
message HelloRequest {
    string name = 1;
}
message HelloReply {
    string message = 1;
}

1. The server-side implements the call to the defined method, noting the server implementation (duck typing).

package main

import (
 "RpcLearn/grpc_test/proto"
 "context"
 "google.golang.org/grpc"
 "log"
 "net"
)

type Server struct {
 proto.UnimplementedGreeterServer // 👈 重点：嵌入这个类型
}

func (s *Server) SayHello(ctx context.Context, req *proto.HelloRequest) (*proto.HelloReply, error) {
 reply := &proto.HelloReply{
  Message: "Hello " + req.Name,
 }
 return reply, nil
}

func main() {
 g := grpc.NewServer()                     // 创建一个新的gRPC服务器
 proto.RegisterGreeterServer(g, &Server{}) // 注册服务
 listener, err := net.Listen("tcp", ":9090")
 if err != nil {
  log.Fatalf("failed to listen: %v", err)
 }
 err = g.Serve(listener)
 if err != nil {
  log.Fatalf("failed to serve: %v", err)
 }
}

1. Client-side call implementation.

package main

import (
 "RpcLearn/grpc_test/proto"
 "context"
 "fmt"
 "google.golang.org/grpc"
 "google.golang.org/grpc/credentials/insecure"
)

func main() {
 // Create a new gRPC server
 //conn, err := grpc.Dial("localhost:9090", grpc.WithInsecure())
 // 使用安全连接
 //creds := credentials.NewTLS(&tls.Config{InsecureSkipVerify: true})
 conn, err := grpc.NewClient("localhost:9090",
  //grpc.WithInsecure()
  grpc.WithTransportCredentials(insecure.NewCredentials()), // ✅ 新方式
 )
 if err != nil {
  panic(err)
 }
 defer conn.Close()
 c := proto.NewGreeterClient(conn)
 r, err := c.SayHello(context.Background(), &proto.HelloRequest{Name: "world"})
 if err != nil {
  panic(err)
 }
 fmt.Println(r.Message)

}

gRPC Stream Method (Streaming Mode)

1. Simple mode (simple RPC)
2. Server-side data stream
3. Client-side data stream
4. Bidirectional

Focused Learning on gRPC

Default values

Default Value Explanation

In Protobuf, different field types have the following default values:

• String type (string): The default value is an empty string.
• Byte type (bytes): The default value is an empty byte sequence.
• Boolean type (bool): The default value is false.
• Numeric types (number types): The default value is 0.
• Enum type: The default value is the first defined enum value, and it must be 0.
• Message type (message): The default value is unset (i.e., null).

Notes

1. For scalar message fields: Once a message is parsed, it's impossible to distinguish whether a field was set to its default value (
   

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