go routines wait group / published by https://github.com/dacr/code-examples-manager #2658bdd8-a0a8-4505-9f15-66b708edf49f/8011b9406efd73965e0883a5d3c92631a82f41d

concurrency-goroutines-wait-group.go

/*?sr/bin/true; exec /usr/bin/env nix-shell -p go --run "go run $0" #*/
// summary : go routines wait group
// keywords : go, goroutines, @testable
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : 2658bdd8-a0a8-4505-9f15-66b708edf49f
// created-on : 2025-03-27T15:17:01+01:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : nix-shell -p go --run "go run $file"
package main

import (
	"fmt"
	"math/rand"
	"sync"
	"time"
)

func main() {
	wg := sync.WaitGroup{}

	for i := range 100 {
		wg.Add(1)
		go func() {
			defer wg.Done() // ALWAYS FIRST !!!
			sleepTime := time.Duration(10+rand.Intn(100)) * time.Millisecond
			time.Sleep(sleepTime)
			fmt.Println(i, sleepTime)
		}()
	}
	wg.Wait()
}