GoToSocial/vendor/github.com/minio/minio-go/v7/retry-continous.go

70 lines
1.9 KiB
Go

/*
* MinIO Go Library for Amazon S3 Compatible Cloud Storage
* Copyright 2015-2017 MinIO, Inc.
*
* 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 minio
import "time"
// newRetryTimerContinous creates a timer with exponentially increasing delays forever.
func (c *Client) newRetryTimerContinous(unit time.Duration, cap time.Duration, jitter float64, doneCh chan struct{}) <-chan int {
attemptCh := make(chan int)
// normalize jitter to the range [0, 1.0]
if jitter < NoJitter {
jitter = NoJitter
}
if jitter > MaxJitter {
jitter = MaxJitter
}
// computes the exponential backoff duration according to
// https://www.awsarchitectureblog.com/2015/03/backoff.html
exponentialBackoffWait := func(attempt int) time.Duration {
// 1<<uint(attempt) below could overflow, so limit the value of attempt
maxAttempt := 30
if attempt > maxAttempt {
attempt = maxAttempt
}
// sleep = random_between(0, min(cap, base * 2 ** attempt))
sleep := unit * time.Duration(1<<uint(attempt))
if sleep > cap {
sleep = cap
}
if jitter != NoJitter {
sleep -= time.Duration(c.random.Float64() * float64(sleep) * jitter)
}
return sleep
}
go func() {
defer close(attemptCh)
var nextBackoff int
for {
select {
// Attempts starts.
case attemptCh <- nextBackoff:
nextBackoff++
case <-doneCh:
// Stop the routine.
return
}
time.Sleep(exponentialBackoffWait(nextBackoff))
}
}()
return attemptCh
}