add grpc

Author: harleyzhao(赵政)

README.md

@@ -79,6 +79,10 @@
 
 [protobuff_hellworld](./note/protobuff_with_golang_tutorial.md)
 
+### grpc 
+
+[grpc](./note/grpc_helloworld.md)
+
 
 > [kafka-todo]
 

note/grpc_helloworld.md

@@ -0,0 +1,133 @@
+# grpc 
+
+## 目录
+
+* [grpc helloworld例子](#helloworld)
+
+---
+
+## helloworld 
+
+目录结构：
+```
+├── client.go
+├── helloworld
+│   ├── build.sh
+│   ├── helloworld.pb.go
+│   └── helloworld.proto
+└── server.go
+```
+
+proto 定义
+```
+syntax = "proto3";
+
+package helloworld;
+
+service Greeter {
+    rpc SayHello (Helloreq) returns (Hellorsp) {}
+}
+
+message Helloreq {
+    string message = 1;
+}
+
+message Hellorsp {
+    string message = 1;
+}
+```
+
+构建
+```
+protoc -I . --go_out=plugins=grpc:. ./helloworld.proto
+```
+
+sever.go 
+```
+package main
+
+import (
+	"context"
+	"log"
+	"net"
+
+	pb "./helloworld"
+	"google.golang.org/grpc"
+)
+
+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.Helloreq) (*pb.Hellorsp, error) {
+	log.Printf("Received: %v", in.GetMessage())
+	return &pb.Hellorsp{Message: "Hello " + in.GetMessage()}, 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)
+	}
+}
+
+```
+
+client.go 
+```
+package main
+
+import (
+	"context"
+	"log"
+	"os"
+	"time"
+
+	pb "./helloworld"
+	"google.golang.org/grpc"
+)
+
+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.
+	message := defaultName
+	if len(os.Args) > 1 {
+		message = os.Args[1]
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+	r, err := c.SayHello(ctx, &pb.Helloreq{Message: message})
+	if err != nil {
+		log.Fatalf("could not greet: %v", err)
+	}
+	log.Printf("Greeting: %s", r.GetMessage())
+}
+```
+
+```
+go run server.go 
+go run client.go 
+```