protolab/server/main.go

package main

import (
	"fmt"
	"log"
	"net"
	"time"

	pb "gordenko.dev/dima/protolab/gen/service/v1"

	"gordenko.dev/dima/protolab/bin"
)

const (
	Port = 8080
)

func handleConnection(conn net.Conn) {
	defer conn.Close()
	log.Printf("client %s connected\n", conn.RemoteAddr().String())

	for {
		var (
			reqWrapper  pb.RequestWrapper
			respWrapper *pb.ResponseWrapper
		)

		err := bin.ReadMessage(conn, &reqWrapper)
		if err != nil {
			log.Fatalf("read request: %v\n", err)
		}

		switch p := reqWrapper.Payload.(type) {
		case *pb.RequestWrapper_SendTelemetry:
			data := p.SendTelemetry
			log.Printf("telemetry received from %s: Temp %.2f°C, BatteryLevel %v%%\n",
				data.GetDeviceId(), data.GetTemperature(), data.GetBatteryLevel())

			respWrapper = &pb.ResponseWrapper{
				Payload: &pb.ResponseWrapper_TelemetryResp{
					TelemetryResp: &pb.TelemetryResponse{
						ResultCode: pb.TelemetryResponse_RESULT_CODE_SUCCEEDED,
					},
				},
			}

		case *pb.RequestWrapper_Ping:
			data := p.Ping
			log.Printf("ping received, client time %s\n",
				time.Unix(data.GetTimestamp(), 0).Format(time.RFC3339))

			respWrapper = &pb.ResponseWrapper{
				Payload: &pb.ResponseWrapper_PingResp{
					PingResp: &pb.PingResponse{
						ServerTimestamp: time.Now().Unix(),
					},
				},
			}

		default:
			log.Printf("unknown request received: %T\n", p)
		}

		err = bin.WriteMessage(conn, respWrapper)
		if err != nil {
			log.Fatalf("send response: %v\n", err)
		} else {
			log.Println("response sent")
		}
	}
}

func main() {
	listener, err := net.Listen("tcp", fmt.Sprintf(":%d", Port))
	if err != nil {
		log.Fatalf("net.Listen: %v\n", err)
	}
	defer listener.Close()

	log.Printf("server started on port %d", Port)

	for {
		conn, err := listener.Accept()
		if err != nil {
			log.Printf("listener.Accept: %v", err)
			continue
		}
		go handleConnection(conn)
	}
}