Курнат Андрей
45 lines
1.1 KiB
Go
45 lines
1.1 KiB
Go
// Copyright 2018 The OPA Authors. All rights reserved.
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// Use of this source code is governed by an Apache2
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// license that can be found in the LICENSE file.
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package util
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import (
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"math/rand"
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"time"
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)
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// DefaultBackoff returns a delay with an exponential backoff based on the
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// number of retries.
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func DefaultBackoff(base, maxNS float64, retries int) time.Duration {
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return Backoff(base, maxNS, .2, 1.6, retries)
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}
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// Backoff returns a delay with an exponential backoff based on the number of
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// retries. Same algorithm used in gRPC.
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// Note that if maxNS is smaller than base, the backoff will still be capped at
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// maxNS.
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func Backoff(base, maxNS, jitter, factor float64, retries int) time.Duration {
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if retries == 0 {
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return 0
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}
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backoff, maxNS := base, maxNS
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for backoff < maxNS && retries > 0 {
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backoff *= factor
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retries--
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}
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if backoff > maxNS {
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backoff = maxNS
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}
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// Randomize backoff delays so that if a cluster of requests start at
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// the same time, they won't operate in lockstep.
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backoff *= 1 + jitter*(rand.Float64()*2-1)
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if backoff < 0 {
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return 0
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}
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return time.Duration(backoff)
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}
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