package main

import (
	"app/grpc-testing-server/api/echo"
	"context"
	"fmt"
	"log"
	"net"

	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

type EchoServer struct {
    // 增加计数
	count int
	echo.UnimplementedEchoServer
}

func (e *EchoServer) Echo(ctx context.Context, par *echo.EchoRequest) (*echo.EchoResponse, error) {
	fmt.Println("echo")
	e.count++
    // 模拟失败
	if e.count%3 != 0 {
		return nil, status.Error(codes.Unavailable, "Unavailable")
	}
	result := &echo.EchoResponse{
		Msg: par.GetMsg(),
	}
	return result, nil
}

func main() {
	log.Println("Go")
	listen, err := net.Listen("tcp", ":8080")
	if err != nil {
		log.Fatalf("failed to listen: %v", err)
	}
	s := grpc.NewServer()
	echo.RegisterEchoServer(s, &EchoServer{})
	if err := s.Serve(listen); err != nil {
		log.Fatalf("failed to serve: %v", err)
	}
}

package main

import (
	"app/grpc-testing-client/api/echo"
	"context"
	"log"

	"google.golang.org/grpc"
)

func main() {
    // 通过 serviceConfig 配置服务 retry 
	scsource := `{
		"methodConfig": [{
		  "name": [{"service": "echo.echo","method":"Echo"}],
		  "retryPolicy": {
			  "MaxAttempts": 4,
			  "InitialBackoff": ".01s",
			  "MaxBackoff": ".1s",
			  "BackoffMultiplier": 1.0,
			  "RetryableStatusCodes": [ "UNAVAILABLE" ]
		  }
		}]}`

	conn, err := grpc.Dial("127.0.0.1:8080", grpc.WithInsecure(), grpc.WithBlock(), grpc.WithDefaultServiceConfig(scsource))
	if err != nil {
		log.Fatalf("did not connect: %v", err)
	}
	defer conn.Close()

	for i := 0; i < 10; i++ {
		c := echo.NewEchoClient(conn)
		ctx, cancle := context.WithCancel(context.Background())
		defer cancle()
		r, err := c.Echo(ctx, &echo.EchoRequest{Msg: "hello"})
		if err != nil {
			log.Fatalf("echo failed :%#v", err)
		}
		log.Print(r.GetMsg())
	}
}