tvl-depot/fun/clbot/backoffutil/backoffutil.go
Luke Granger-Brown 9099497185 chore(clbot): Refactor backoff utility into a separate package.
It'll be reused by the IRC side of things too.

Change-Id: I3d84f3fd5fca6a6d948f331143b14f096d10675d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/342
Reviewed-by: tazjin <mail@tazj.in>
2020-06-15 16:48:58 +00:00

43 lines
1.4 KiB
Go

// Package backoffutil provides useful utilities for backoff.
package backoffutil
import (
"time"
backoff "github.com/cenkalti/backoff/v4"
)
// ZeroStartingBackOff is a backoff.BackOff that returns "0" as the first Duration after a reset.
// This is useful for constructing loops and just enforcing a backoff duration on every loop, rather than incorporating this logic into the loop directly.
type ZeroStartingBackOff struct {
bo backoff.BackOff
initial bool
}
// NewZeroStartingBackOff creates a new ZeroStartingBackOff.
func NewZeroStartingBackOff(bo backoff.BackOff) *ZeroStartingBackOff {
return &ZeroStartingBackOff{bo: bo, initial: true}
}
// NewDefaultBackOff creates a sensibly configured BackOff that starts at zero.
func NewDefaultBackOff() backoff.BackOff {
ebo := backoff.NewExponentialBackOff()
ebo.MaxElapsedTime = 0
return NewZeroStartingBackOff(ebo)
}
// NextBackOff returns the next back off duration to use.
// For the first call after a call to Reset(), this is 0. For each subsequent duration, the underlying BackOff is consulted.
func (bo *ZeroStartingBackOff) NextBackOff() time.Duration {
if bo.initial == true {
bo.initial = false
return 0
}
return bo.bo.NextBackOff()
}
// Reset resets to the initial state, and also passes a Reset through to the underlying BackOff.
func (bo *ZeroStartingBackOff) Reset() {
bo.initial = true
bo.bo.Reset()
}