mirror of
https://github.com/octoleo/restic.git
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39 lines
1.2 KiB
Go
39 lines
1.2 KiB
Go
// Copyright 2018, OpenCensus Authors
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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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package ocagent
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import (
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"math/rand"
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"time"
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)
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var randSrc = rand.New(rand.NewSource(time.Now().UnixNano()))
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// retries function fn upto n times, if fn returns an error lest it returns nil early.
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// It applies exponential backoff in units of (1<<n) + jitter microsends.
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func nTriesWithExponentialBackoff(nTries int64, timeBaseUnit time.Duration, fn func() error) (err error) {
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for i := int64(0); i < nTries; i++ {
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err = fn()
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if err == nil {
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return nil
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}
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// Backoff for a time period with a pseudo-random jitter
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jitter := time.Duration(randSrc.Float64()*100) * time.Microsecond
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ts := jitter + ((1 << uint64(i)) * timeBaseUnit)
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<-time.After(ts)
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}
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return err
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}
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