Go の gRPC で Redis のデータを作成 (Create)

設定ファイル、サーバープログラム、クライアントプログラムの３つが必要です。

```text
$ tree
.
├── redis_create
│   └── redis_create.proto
├── redis_create_client
│   └── main.go
└── redis_create_server
    └── main.go
```

設定ファイル

```text:redis_create/redis_create.proto

syntax = "proto3";

package redis_create;

service Greeter {
	rpc RedisCreate (RedisRequest) returns (RedisReply) {}
}

message RedisRequest {
	string key = 1;
	string strjson = 2;
}

message RedisReply {
	string key = 1;
}
```

サーバープログラム

```go:redis_create_server/main.go
// ---------------------------------------------------------------
//
//	redis_create_server/main.go
//
//					Feb/12/2020	
// ---------------------------------------------------------------
package main

import (
	"context"
	"log"
	"net"
	"fmt"
	"os"

	"google.golang.org/grpc"
	pb "../redis_create"
)

const (
	port = ":50051"
)

type server struct {
	pb.UnimplementedGreeterServer
}

// ---------------------------------------------------------------
func redis_socket_write_proc (conn net.Conn,key_in string,json_str string) {
	fmt.Println (key_in)
	fmt.Println (json_str)

	comm_aa := "set " + key_in + " '" + json_str + "'\r\n"
	conn.Write([]byte(comm_aa))


	buf := make ([]byte,1024)
	conn.Read (buf[:])

	fmt.Println (string(buf[0:10]))
}

// ---------------------------------------------------------------
func redis_create_proc (key_in string,str_json string) string {

	hostname := "localhost"
	port := "6379"

	conn, err := net.Dial ("tcp", hostname + ":" + port)
	if err != nil {
		fmt.Println(err)
		return str_json
		}

	fmt.Fprintf (os.Stderr,"str_json = " + str_json + "\n")
	redis_socket_write_proc (conn,key_in,str_json)

	return key_in
}
// ---------------------------------------------------------------
func (s *server) RedisCreate(ctx context.Context, in *pb.RedisRequest) (*pb.RedisReply, error) {
	fmt.Fprintf (os.Stderr,"*** check aaa ***\n")
	key := in.GetKey()
	str_json := in.GetStrjson()
	fmt.Fprintf (os.Stderr,"key = " + key + "\n")
	fmt.Fprintf (os.Stderr,"str_json = " + str_json + "\n")
	redis_create_proc (key,str_json)
	return &pb.RedisReply{Key: key }, 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)
	}
}

// ---------------------------------------------------------------
```

クライアントプログラム

```go:redis_create_client/main.go
// ---------------------------------------------------------------
//
//	redis_create_client/main.go
//
//					Feb/12/2020
//
// ---------------------------------------------------------------
package main

import (
	"context"
	"fmt"
	"log"
	"os"
	"encoding/json"
	"strconv"
	"time"

	"google.golang.org/grpc"
	pb "../redis_create"
)

const (
	address     = "localhost:50051"
	defaultKey = "t0001"
	defaultName = "aaaa"
	defaultPopulation = 1
	defaultDate_mod = "2000-01-01"
)

// ---------------------------------------------------------------
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.
	key := defaultKey
	unit_aa := make(map[string]interface{})
	unit_aa["name"] = defaultName
	unit_aa["population"] = defaultPopulation
	unit_aa["date_mod"] = defaultDate_mod
	if len(os.Args) > 1 {
		key = os.Args[1]
		unit_aa["name"] = os.Args[2]
		unit_aa["population"],_ = strconv.Atoi (os.Args[3])
		unit_aa["date_mod"] = os.Args[4]
	}
	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()
	output, _ := json.Marshal(unit_aa)
	str_json := string(output)	
	r, err := c.RedisCreate(ctx, &pb.RedisRequest{Key: key,Strjson: str_json})
	if err != nil {
		log.Fatalf("could not greet: %v", err)
	}

	rvalue := r.GetKey()

	fmt.Printf ("%s\n",rvalue)
}

// ---------------------------------------------------------------
```

gRPC のコードを作成します。

スクリプト

```bash
protoc -I redis_create redis_create/redis_create.proto --go_out=plugins=grpc:redis_create
```

サーバープログラムの起動

```bash
go run redis_create_server/main.go
```

クライアントプログラムの実行

```text
$ go run redis_create_client/main.go t0934  那須烏山 42938 2003-9-22
t0934
```