waiterr/example_test.go

package waiterr_test

import (
	"context"
	"errors"
	"fmt"
	"time"

	"codeberg.org/danjones000/waiterr"
)

func Example() {
	we := waiterr.New()
	we.Go(func() error {
		time.Sleep(100 * time.Millisecond)
		fmt.Println("Goroutine 1 finished")
		return nil
	})

	we.Go(func() error {
		time.Sleep(50 * time.Millisecond)
		fmt.Println("Goroutine 2 finished with an error")
		return errors.New("something went wrong in goroutine 2")
	})

	we.Go(func() error {
		time.Sleep(150 * time.Millisecond)
		fmt.Println("Goroutine 3 finished")
		return nil
	})

	// Wait for all goroutines and get all errors
	if err := we.Wait(); err != nil {
		fmt.Printf("All goroutines finished. Combined error:\n%v\n", err)
	}

	// Output:
	// Goroutine 2 finished with an error
	// Goroutine 1 finished
	// Goroutine 3 finished
	// All goroutines finished. Combined error:
	// something went wrong in goroutine 2
}

func ExampleWaitErr_WaitForError() {
	we := waiterr.New()
	we.Go(func() error {
		time.Sleep(100 * time.Millisecond)
		return errors.New("first error from we")
	})
	we.Go(func() error {
		time.Sleep(50 * time.Millisecond)
		return errors.New("second error from we")
	})

	if err := we.WaitForError(); err != nil {
		fmt.Printf("First error returned from we: %v\n", err)
	}

	// Output:
	// First error returned from we: second error from we

}

func ExampleWaitErr_Unwrap() {
	we := waiterr.New()
	we.Go(func() error {
		time.Sleep(100 * time.Millisecond)
		return errors.New("first error from we")
	})
	we.Go(func() error {
		time.Sleep(50 * time.Millisecond)
		return errors.New("second error from we")
	})
	we.Go(func() error {
		time.Sleep(75 * time.Millisecond)
		return nil
	})

	_ = we.Wait()

	errs := we.Unwrap()
	for _, e := range errs {
		fmt.Println(e)
	}

	// Output:
	// second error from we
	// first error from we
}

func ExampleWithContext() {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	we, ctx := waiterr.WithContext(ctx)

	we.Go(func() error {
		select {
		case <-time.After(100 * time.Millisecond):
			fmt.Println("Goroutine 1 finished")
			return nil
		case <-ctx.Done():
			return ctx.Err()
		}
	})

	we.Go(func() error {
		select {
		case <-time.After(50 * time.Millisecond):
			fmt.Println("Goroutine 2 finished with an error")
			return errors.New("something went wrong in goroutine 2")
		case <-ctx.Done():
			return ctx.Err()
		}
	})

	we.Go(func() error {
		select {
		case <-time.After(150 * time.Millisecond):
			fmt.Println("Goroutine 3 finished")
			return nil
		case <-ctx.Done():
			return ctx.Err()
		}
	})

	if err := we.Wait(); err != nil {
		fmt.Printf("All goroutines finished. Combined error: %s\n", err)
	}

	// Output:
	// Goroutine 2 finished with an error
	// All goroutines finished. Combined error: something went wrong in goroutine 2
	// context canceled
	// context canceled
}