73 lines
1.7 KiB
Go
73 lines
1.7 KiB
Go
|
// Copyright 2017 Google Inc. All Rights Reserved.
|
||
|
|
//
|
||
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
|
// you may not use this file except in compliance with the License.
|
||
|
|
// You may obtain a copy of the License at
|
||
|
|
//
|
||
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
//
|
||
|
|
// Unless required by applicable law or agreed to in writing, software
|
||
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
|
// See the License for the specific language governing permissions and
|
||
|
|
// limitations under the License.
|
||
|
|
|
||
|
|
package jsonclient
|
||
|
|
|
||
|
|
import (
|
||
|
|
"sync"
|
||
|
|
"time"
|
||
|
|
)
|
||
|
|
|
||
|
|
type backoff struct {
|
||
|
|
mu sync.RWMutex
|
||
|
|
multiplier uint
|
||
|
|
notBefore time.Time
|
||
|
|
}
|
||
|
|
|
||
|
|
const (
|
||
|
|
// maximum backoff is 2^(maxMultiplier-1) = 128 seconds
|
||
|
|
maxMultiplier = 8
|
||
|
|
)
|
||
|
|
|
||
|
|
func (b *backoff) set(override *time.Duration) time.Duration {
|
||
|
|
b.mu.Lock()
|
||
|
|
defer b.mu.Unlock()
|
||
|
|
if b.notBefore.After(time.Now()) {
|
||
|
|
if override != nil {
|
||
|
|
// If existing backoff is set but override would be longer than
|
||
|
|
// it then set it to that.
|
||
|
|
notBefore := time.Now().Add(*override)
|
||
|
|
if notBefore.After(b.notBefore) {
|
||
|
|
b.notBefore = notBefore
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return time.Until(b.notBefore)
|
||
|
|
}
|
||
|
|
var wait time.Duration
|
||
|
|
if override != nil {
|
||
|
|
wait = *override
|
||
|
|
} else {
|
||
|
|
if b.multiplier < maxMultiplier {
|
||
|
|
b.multiplier++
|
||
|
|
}
|
||
|
|
wait = time.Second * time.Duration(1<<(b.multiplier-1))
|
||
|
|
}
|
||
|
|
b.notBefore = time.Now().Add(wait)
|
||
|
|
return wait
|
||
|
|
}
|
||
|
|
|
||
|
|
func (b *backoff) decreaseMultiplier() {
|
||
|
|
b.mu.Lock()
|
||
|
|
defer b.mu.Unlock()
|
||
|
|
if b.multiplier > 0 {
|
||
|
|
b.multiplier--
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (b *backoff) until() time.Time {
|
||
|
|
b.mu.RLock()
|
||
|
|
defer b.mu.RUnlock()
|
||
|
|
return b.notBefore
|
||
|
|
}
|