Go by Example: WaitGroups

A WaitGroup is a type in Go’s standard library that allows multiple goroutines to wait for a set of operations to complete. It’s used to wait for a collection of Goroutines to finish.

Here’s an example of using a WaitGroup:

package main

import (
	"fmt"
	"sync"
)

func worker(id int, wg *sync.WaitGroup) {
	defer wg.Done()
	fmt.Printf("worker %d starting\n", id)
	// perform work here
	fmt.Printf("worker %d done\n", id)
}

func main() {
	var wg sync.WaitGroup

	for i := 1; i <= 5; i++ {
		wg.Add(1)
		go worker(i, &wg)
	}

	wg.Wait()
	fmt.Println("All workers done")
}

In this example, 5 worker goroutines are started and the WaitGroup wg is used to wait for all of them to complete. The Add method is used to add the number of Goroutines to wait for. The Done method is used to decrement the wait group count when a Goroutine finishes. The Wait method blocks until the count of the WaitGroup goes back to zero.