How to Implement Cancellation Propagation Trees in Go

Concurrency
2026-04-17T12:05:42+00:00
Implement cancellation propagation in Go by passing a shared context to child goroutines and using errgroup to cancel all tasks on the first error.

Go does not have a built-in "cancellation propagation tree"; you implement it by passing a context.Context down to child goroutines and using context.WithCancelCause to propagate errors. Use golang.org/x/sync/errgroup to manage the group and automatically cancel all children when the first one fails.

package main

import (
	"context"
	"fmt"
	"time"

	"golang.org/x/sync/errgroup"
)

func main() {
	ctx, cancel := context.WithCancelCause(context.Background())
	g, ctx := errgroup.WithContext(ctx)

	// Parent task
	g.Go(func() error {
		<-ctx.Done()
		return ctx.Err()
	})

	// Child tasks
	for i := 0; i < 3; i++ {
		g.Go(func() error {
			select {
			case <-time.After(2 * time.Second):
				return fmt.Errorf("task %d failed", i)
			case <-ctx.Done():
				return ctx.Err()
			}
		})
	}

	if err := g.Wait(); err != nil {
		fmt.Println("Group failed:", err)
	}
}