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- /*
- * 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
- }
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