context studies

main.go

package main

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

func main() {
	ctx, cancel := context.WithTimeout(
		context.Background(),
		time.Duration(3*time.Second))

	defer cancel()

	go func(ctx context.Context) {
		defer cancel()

		simulate a process that takes 2 second to complete
		time.Sleep(1 * time.Second)
	}(ctx)

	select {
	case <-ctx.Done():
		switch ctx.Err() {
		case context.DeadlineExceeded:
			fmt.Println("context timeout exceeded")
		case context.Canceled:
			// spew.Dump(context)

			fmt.Println("context cancelled by force. whole process is complete")
		}
	case <-time.After(2 * time.Second): // Successfully
		fmt.Println("without error")
	}
}