go-backoff

Backoff algorithm and helpers for Go

SYNOPSIS

import "github.com/lestrrat-go/backoff"

func Func(arg Foo) (Result, error) { ... }

var policy = backoff.NewExponential(
  backoff.WithInterval(500*time.Millisecond), // base interval
  backoff.WithJitterFactor(0.05), // 5% jitter
  backoff.WithMaxRetries(25),
)
func RetryFunc(arg Foo) (Result, error) {
  b, cancel := policy.Start(context.Background())
  defer cancel()

  for backoff.Continue(b) {
    res, err := Func(arg)
    if err == nil {
      return res, nil
    }
  }
  return nil, errors.New(`tried very hard, but no luck`)
}

Simple Usage

func ExampleRetry() {
  count := 0
  e := backoff.ExecuteFunc(func(_ context.Context) error {
    // This is a silly example that succeeds on every 10th try
    count++
    if count%10 == 0 {
      return nil
    }
    return errors.New(`dummy`)
  })

  ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
  defer cancel()

  p := backoff.NewExponential()
  if err := backoff.Retry(ctx, p, e); err != nil {
    log.Printf("failed to call function after repeated tries")
  }
}

DESCRIPTION

This library is an implementation of backoff algorithm for retrying operations in an idiomatic Go way. It respects context.Context natively, and the critical notifications are done through channel operations, allowing you to write code that is both more explicit and flexibile.

It also exports a utility function Retry, for simple operations.

For a longer discussion, please read this article

TODO

Refine the timeouts generated by exponential backoff algorithm (help wanted!)

PRIOR ARTS

github.com/cenkalti/backoff

This library is featureful, but one thing that gets to me is the fact that it essentially forces you to create a closure over the operation to be retried.

github.com/jpillora/backoff

This library is a very simple implementation of calculating backoff durations. I wanted it to let me know when to stop too, so it was missing a few things.

DUMB BENCHMARK

make benchmark
go test -run=none -tags bench -bench . -benchmem -benchtime 20s
goos: darwin
goarch: amd64
pkg: github.com/lestrrat-go/backoff
Benchmark/cenkalti-4         	       3	6828914804 ns/op	    1205 B/op	      24 allocs/op
Benchmark/lestrrat-4         	       5	4842358461 ns/op	    1022 B/op	      20 allocs/op
PASS
ok  	github.com/lestrrat-go/backoff	70.711s

iandri / backoff