Example_parentCancelsChildren.go

package main

import (
	"context"
	"fmt"
)

func Example_parentCancelsChildren() {
	parentCtx, cancelParentCtx := context.WithCancel(context.Background())
	interimValCtx := context.WithValue(parentCtx, "foo", "bar")
	childCtx, cancelChildCtx := context.WithCancel(interimValCtx)
	defer cancelChildCtx()
	defer cancelParentCtx()

	cancelParentCtx()

	fmt.Println("parent:", parentCtx.Err())
	fmt.Println("interim:", interimValCtx.Err())
	fmt.Println("child:", childCtx.Err())
	// Output:
	// parent: context canceled
	// interim: context canceled
	// child: context canceled
}