Wait for all Go routines to finish execution in Golang

sync package of golang provides WaitGroup struct which can be used to wait for collection of goroutines to finish execution. The WaitGroup provides:

• Add method to set the number of goroutines to wait for.

• Done method which is called by each of the goroutines when finished.

• Wait method which is used to block till all goroutines have finished and have called the Done method

Let’s see a working code

package main

import (
    "fmt"
    "sync"
    "time"
)

func main() {
    var wg sync.WaitGroup
    wg.Add(2)
 
    go sleep(&wg, time.Second*1)
    go sleep(&wg, time.Second*2)
 
    wg.Wait()
    fmt.Println("All goroutines finished")
}

func sleep(wg *sync.WaitGroup, t time.Duration) {
    defer wg.Done()
    time.Sleep(t)
    fmt.Println("Finished Execution")
}

Output:

Finished Execution
Finished Execution
All goroutines finished