126 lines
3.6 KiB
Go
126 lines
3.6 KiB
Go
/*
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* MinIO Go Library for Amazon S3 Compatible Cloud Storage
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* Copyright 2015-2017 MinIO, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package minio
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import (
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"context"
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"net/http"
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"time"
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)
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// MaxRetry is the maximum number of retries before stopping.
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var MaxRetry = 10
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// MaxJitter will randomize over the full exponential backoff time
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const MaxJitter = 1.0
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// NoJitter disables the use of jitter for randomizing the exponential backoff time
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const NoJitter = 0.0
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// DefaultRetryUnit - default unit multiplicative per retry.
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// defaults to 200 * time.Millisecond
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var DefaultRetryUnit = 200 * time.Millisecond
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// DefaultRetryCap - Each retry attempt never waits no longer than
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// this maximum time duration.
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var DefaultRetryCap = time.Second
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// newRetryTimer creates a timer with exponentially increasing
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// delays until the maximum retry attempts are reached.
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func (c *Client) newRetryTimer(ctx context.Context, maxRetry int, unit time.Duration, cap time.Duration, jitter float64) <-chan int {
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attemptCh := make(chan int)
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// computes the exponential backoff duration according to
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// https://www.awsarchitectureblog.com/2015/03/backoff.html
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exponentialBackoffWait := func(attempt int) time.Duration {
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// normalize jitter to the range [0, 1.0]
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if jitter < NoJitter {
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jitter = NoJitter
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}
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if jitter > MaxJitter {
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jitter = MaxJitter
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}
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// sleep = random_between(0, min(cap, base * 2 ** attempt))
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sleep := unit * time.Duration(1<<uint(attempt))
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if sleep > cap {
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sleep = cap
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}
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if jitter != NoJitter {
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sleep -= time.Duration(c.random.Float64() * float64(sleep) * jitter)
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}
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return sleep
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}
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go func() {
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defer close(attemptCh)
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for i := 0; i < maxRetry; i++ {
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select {
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case attemptCh <- i + 1:
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case <-ctx.Done():
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return
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}
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select {
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case <-time.After(exponentialBackoffWait(i)):
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case <-ctx.Done():
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return
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}
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}
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}()
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return attemptCh
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}
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// List of AWS S3 error codes which are retryable.
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var retryableS3Codes = map[string]struct{}{
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"RequestError": {},
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"RequestTimeout": {},
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"Throttling": {},
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"ThrottlingException": {},
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"RequestLimitExceeded": {},
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"RequestThrottled": {},
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"InternalError": {},
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"ExpiredToken": {},
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"ExpiredTokenException": {},
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"SlowDown": {},
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// Add more AWS S3 codes here.
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}
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// isS3CodeRetryable - is s3 error code retryable.
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func isS3CodeRetryable(s3Code string) (ok bool) {
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_, ok = retryableS3Codes[s3Code]
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return ok
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}
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// List of HTTP status codes which are retryable.
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var retryableHTTPStatusCodes = map[int]struct{}{
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429: {}, // http.StatusTooManyRequests is not part of the Go 1.5 library, yet
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499: {}, // client closed request, retry. A non-standard status code introduced by nginx.
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http.StatusInternalServerError: {},
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http.StatusBadGateway: {},
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http.StatusServiceUnavailable: {},
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http.StatusGatewayTimeout: {},
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// Add more HTTP status codes here.
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}
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// isHTTPStatusRetryable - is HTTP error code retryable.
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func isHTTPStatusRetryable(httpStatusCode int) (ok bool) {
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_, ok = retryableHTTPStatusCodes[httpStatusCode]
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return ok
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}
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