go-routines-context.go

package main

import (
	"context"
	"fmt"
	"time"
)

func perform(ctx *context.Context, name string, out chan<- string) {
	for {
		if ctx != nil {
			select {
			case t := <-time.After(time.Second):
				fmt.Printf("\n%d\n", t.Second())
				// just continue here
			case <-(*ctx).Done():
				return
			case out <- name:
				// return name on chan
			}
		} else {
			fmt.Println(name)
			time.Sleep(time.Second)
		}
	}
}

func start() {
	duration, err := time.ParseDuration("5s")
	if err != nil {
		panic(err)
	}

	performOut := make(chan string)
	ctx, cancel := context.WithTimeout(context.Background(), duration)
	defer func() {
		fmt.Println("Cancel routines")
		cancel()
	}()
	perform(&ctx, "routines", performOut)
}
func main() {
	go start()
	perform(nil, "main", nil)
}