mirror of
https://github.com/rclone/rclone.git
synced 2024-11-30 04:15:26 +01:00
47 lines
1.2 KiB
Go
47 lines
1.2 KiB
Go
// Copyright 2016 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package gensupport
|
|
|
|
import (
|
|
"math/rand"
|
|
"time"
|
|
)
|
|
|
|
type BackoffStrategy interface {
|
|
// Pause returns the duration of the next pause and true if the operation should be
|
|
// retried, or false if no further retries should be attempted.
|
|
Pause() (time.Duration, bool)
|
|
|
|
// Reset restores the strategy to its initial state.
|
|
Reset()
|
|
}
|
|
|
|
// ExponentialBackoff performs exponential backoff as per https://en.wikipedia.org/wiki/Exponential_backoff.
|
|
// The initial pause time is given by Base.
|
|
// Once the total pause time exceeds Max, Pause will indicate no further retries.
|
|
type ExponentialBackoff struct {
|
|
Base time.Duration
|
|
Max time.Duration
|
|
total time.Duration
|
|
n uint
|
|
}
|
|
|
|
func (eb *ExponentialBackoff) Pause() (time.Duration, bool) {
|
|
if eb.total > eb.Max {
|
|
return 0, false
|
|
}
|
|
|
|
// The next pause is selected from randomly from [0, 2^n * Base).
|
|
d := time.Duration(rand.Int63n((1 << eb.n) * int64(eb.Base)))
|
|
eb.total += d
|
|
eb.n++
|
|
return d, true
|
|
}
|
|
|
|
func (eb *ExponentialBackoff) Reset() {
|
|
eb.n = 0
|
|
eb.total = 0
|
|
}
|