Errors in Go - context deadline exceeded

What causes the error?

context deadline exceeded error occurs when using context.WithDeadline() and the deadline has expired.

package main

import (
	"context"
	"log"
	"time"
)

func main() {
	var ctx context.Context
	var ctxCancelFunc context.CancelFunc
	var timeTillContextDeadline = time.Now().Add(3 * time.Second)

	ctx, ctxCancelFunc = context.WithDeadline(context.Background(), timeTillContextDeadline)
	defer ctxCancelFunc()

	time.Sleep(5 * time.Second) //Sleep simulates time your program was doing something
	
	//Check context for error, If ctx.Err() != nil gracefully exit the current execution
	if ctx.Err() != nil {
		log.Println(ctx.Err())
	}
}

How can I fix it?

In most cases this isn’t an error you would fix. This is simple a signal that your code should stop and gracefully exit what its doing.