ships_backend/main.go

package main

import (
	"fmt"
	"log"
	"os"
	"time"

	"daydev.org/shipsgs/internal/config"
	"daydev.org/shipsgs/internal/gameServer"
	"daydev.org/shipsgs/internal/server"
	"daydev.org/shipsgs/internal/utils"
	"github.com/xlab/closer"
)

var Logger *utils.Logger
var ch_sighup *chan bool

//channel to shutdown oneSecUpdater
var ch_oneSecUpdaterShutdown chan bool

//GameServer Public Global Instance
var GS *gameServer.GameServer

func main() {
	logFile, err := os.OpenFile("runlog.log", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		fmt.Println(err)
	} else {
		log.SetOutput(logFile)
	}
	defer logFile.Close()

	closer.Bind(cleanup)

	//Can be optimised to NEW instead of MAKE
	sighup := make(chan bool)
	ch_sighup = &sighup

	ch_oneSecUpdaterShutdown = make(chan bool)

	//If debug - fill Stdout too - LOG to use?
	//Logger = utils.New(os.Stdout, utils.LevelInfo)

	config.ReadConfig()

	GS = new(gameServer.GameServer)
	GS.Init(Logger, &config.Config)
	go GS.Update()

	//Starting oneSecUpdater after GameServer is ready, because oneSecUpdater
	// is depending on GameServer.Shutdown channel which
	// is IF uninitialized we will get "invalid memory address or nil pointer dereference"
	go oneSecUpdater()

	log.Println("Starting Healthy")

	//closer.Hold()
	server.SetupAndRun(":8080", ch_sighup, GS)

	GS.WG.Wait()

}

func cleanup() {
	fmt.Println("Shutting down ")

	//Shutting down oneSecUpdater
	ch_oneSecUpdaterShutdown <- true

	//Investigate why no messages on correct closing
	GS.Shutdown <- true

	// Main function has to be closed the last
	*ch_sighup <- true

	Logger.PrintInfo("main", map[string]string{
		"Info": "Closing Application Normally",
	})

}

func oneSecUpdater() {
	//The intention here is to awake after 1 second and send an update to GameServer to update everything
	for {
		select {
		case <-ch_oneSecUpdaterShutdown:
			fmt.Println("Shutdown One Sec Updater")
			GS.WG.Done()
			// Goroutine will wait untill the DEFAULT: will happen before shutdown will take
			// any effect
		case <-time.After(time.Second * 1):
			fmt.Println("1 Sec Timer")
		default:
			//*** maybe try this 10 secs in a CASE segment ?
			// This blocks whole goroutine
			<-time.After(time.Second * 2)

			GS.OneSecond <- true
		}
	}

}