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>
This commit is contained in:
Luke Granger-Brown 2020-06-14 21:47:14 +01:00 committed by lukegb
parent 5acd03817a
commit 9099497185
4 changed files with 60 additions and 28 deletions

View file

@ -0,0 +1,43 @@
// 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()
}

View file

@ -0,0 +1,14 @@
{ depot, ... }:
let
inherit (depot.third_party) gopkgs;
in
depot.nix.buildGo.package {
name = "code.tvl.fyi/fun/clbot/backoffutil";
srcs = [
./backoffutil.go
];
deps = [
gopkgs."github.com".cenkalti.backoff.gopkg
];
}

View file

@ -11,7 +11,7 @@ depot.nix.buildGo.package {
];
deps = [
clbot.gerrit.gerritevents
gopkgs."github.com".cenkalti.backoff.gopkg
clbot.backoffutil
gopkgs."github.com".golang.glog.gopkg
gopkgs."golang.org".x.crypto.ssh.gopkg
];

View file

@ -9,35 +9,12 @@ import (
"strings"
"time"
"code.tvl.fyi/fun/clbot/backoffutil"
"code.tvl.fyi/fun/clbot/gerrit/gerritevents"
"github.com/cenkalti/backoff/v4"
log "github.com/golang/glog"
"golang.org/x/crypto/ssh"
)
// 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
}
// 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()
}
// closer provides an embeddable implementation of Close which awaits a main loop acknowledging it has stopped.
type closer struct {
stop chan struct{}
@ -174,9 +151,7 @@ func (c *restartingClient) runOnce() error {
func (c *restartingClient) run() {
defer close(c.stopped)
ebo := backoff.NewExponentialBackOff()
ebo.MaxElapsedTime = 0
bo := &zeroStartingBackOff{bo: ebo, initial: true}
bo := backoffutil.NewDefaultBackOff()
for {
timer := time.NewTimer(bo.NextBackOff())
select {