keisku / backoff

A simple exponential backoff counter.

backoff

A simple exponential backoff counter.

The algorithm is based on google.

install

go get github.com/kskumgk63/backoff

Examples

no options

Repeat alwaysErr() at intervals of backoff time until the timeout occurs.

func alwaysErr() error {
	return errors.New("internal server error")
}

func main() {
	cmd := backoff.NewCommander()
	if timeoutErr := cmd.Exec(alwaysErr); timeoutErr != nil {
		fmt.Println(timeoutErr)
	}
}

After 65s, this message is printed. No messages during exponential backoff loop.

Ends the exponential backoff because of timeout

change timeout

Change the timeout value to 10 seconds.

func alwaysErr() error {
	return errors.New("internal server error")
}

func main() {
	cmd := backoff.NewCommander(
		backoff.Timeout(5 * time.Second),
	)
	if timeoutErr := cmd.Exec(alwaysErr); timeoutErr != nil {
		fmt.Println(timeoutErr)
	}
}

After 5s, this message is printed. No messages during exponential backoff loop.

Ends the exponential backoff because of timeout

abort backoff loop

The backoff loop is aborted when a specific error occurs.

This example below prints nothing, exit 0.

func alwaysErr() error {
	return errors.New("internal server error")
}

func main() {
	cmd := backoff.NewCommander(
		backoff.AbortLoop(func(err error) {
			return err.Error() == "internal server error"
		}),
	)
	if timeoutErr := cmd.Exec(alwaysErr); timeoutErr != nil {
		fmt.Println(timeoutErr)
	}
}

debug mode on

if debug mode is on, prints errors when repeating alwaysErr()

func alwaysErr() error {
	return errors.New("internal server error")
}

func main() {
	cmd := backoff.NewCommander(
		backoff.DebugModeOn(),
	)
	cmd.Exec(alwaysErr)
}

internal server error
waiting 2.020000s...
internal server error
waiting 4.564000s...
internal server error
waiting 8.586000s...
internal server error
waiting 16.869000s...
.
.
.

change debug printer

func alwaysErr() error {
	return errors.New("internal server error")
}

func main() {
	cmd := backoff.NewCommander(
		backoff.Timeout(10*time.Second),
		backoff.DebugModeOn(),
		backoff.DebugPrint(func(err error) {
			fmt.Printf("[ERR] %+v\n", err)
		}),
	)
	if timeoutErr := cmd.Exec(alwaysErr); timeoutErr != nil {
		fmt.Println(timeoutErr)
	}
}

You can change a debug printer!

[ERR] internal server error
waiting 2.088000s...
[ERR] internal server error
waiting 4.904000s...
[ERR] internal server error
waiting 8.212000s...
Ends the exponential backoff because of timeout

See more options.