goroutines-incorrect

goroutines-incorrect.go

package main

import (
	"fmt"
	"net/http"
	"sync"
	"time"

	"github.com/labstack/echo"
	"github.com/labstack/echo/middleware"
)

var wGGlobal sync.WaitGroup
var pollQChannel = make(chan int, 3)
var pollYChannel = make(chan int, 3)

func A(wG *sync.WaitGroup) {
	wG.Add(1)
	defer wG.Done()
	fmt.Println("A")
}

func D(wG *sync.WaitGroup) {
	// missing the call to Add()
	defer wG.Done()
	fmt.Println("C")
}

func B(wG *sync.WaitGroup) {
	defer func() {
		fmt.Println(<-pollQChannel)
	}()
	fmt.Println("B")
	A(wG)
}

func C(wG *sync.WaitGroup) {
	fmt.Println("C")
	defer func() {
		fmt.Println(<-pollYChannel)
	}()
	D(wG)
}

func PollQ() {

	for {
		time.Sleep(10 * time.Second)
		pollQChannel <- 1
		go B(&wGGlobal)
	}

}

func PollY() {

	for {
		time.Sleep(10 * time.Second)
		pollYChannel <- 1
		go C(&wGGlobal)
	}

}

func main() {
	//var wG sync.WaitGroup

	e := echo.New()

	// Middleware
	e.Use(middleware.Logger())
	e.Use(middleware.Recover())

	// Routes
	e.GET("/", hello)

	go PollQ()
	go PollY()

	// Start server
	e.Logger.Fatal(e.Start(":1323"))
}

func hello(c echo.Context) error {
	return c.String(http.StatusOK, "Hello, World!")
}