Simple Go file to understand context cancellation

context-timeout.go

package main

import (
	"context"
	"time"

	log "github.com/sirupsen/logrus"
)

func main() {
	ctx, cancel := context.WithTimeout(context.Background(), time.Second*2)
	defer cancel()
	if err := Close(ctx); err != nil {
		log.Fatalln(err)
	}
}

func long(done chan error) {
	time.Sleep(time.Second * 5)
	done <- nil
}

func Close(ctx context.Context) error {
	done := make(chan error)
	go long(done)
	select {
	case <-ctx.Done():
		return ctx.Err()
	case v := <-done:
		return v
	}
}