Go concurrency long and short task

main.go

package main

import (
        log "github.com/Sirupsen/logrus"
        "sync"
        "time"
)

// work short is done right away
func workShort(id string) {
        log.Infof("[%s] start short work", id)
        time.Sleep(500 * time.Millisecond)
        log.Infof("[%s] stop short work", id)
}

// work long is only once done globaly
func workLong(id string) {
        log.Infof("[%s] start long work", id)
        time.Sleep(5 * time.Second)
        log.Infof("[%s] stop long work", id)
}

func work(wg *sync.WaitGroup, semLong chan bool, id string) {
        wg.Add(1)
        go func() {
                // make sure decrement after leaving this coroutine
                defer wg.Done()
                log.Infof("[%s] start over all work", id)
                workShort(id)
                semLong <- true
                workLong(id)
                <-semLong
                log.Infof("[%s] finish over all work", id)
        }()
}

func main() {
        wg := sync.WaitGroup{}
        maxLong := 2
        semLong := make(chan bool, maxLong)
        work(&wg, semLong, "A")
        time.Sleep(1 * time.Second)
        work(&wg, semLong, "B")
        time.Sleep(2 * time.Second)
        work(&wg, semLong, "C")
        wg.Wait()
}