mirror of https://github.com/linkerd/linkerd2.git
78 lines
2.0 KiB
Go
78 lines
2.0 KiB
Go
// Copyright (c) 2016-2017 Tigera, Inc. All rights reserved.
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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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//NB: This file was copied from: https://github.com/projectcalico/felix/blob/master/jitter/jittered_ticker.go
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package servicemirror
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import (
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"math/rand"
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"time"
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log "github.com/sirupsen/logrus"
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)
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// Ticker tries to emit events on channel C at minDuration intervals plus up to maxJitter.
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type Ticker struct {
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C <-chan time.Time
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stop chan bool
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MinDuration time.Duration
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MaxJitter time.Duration
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}
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// NewTicker creates a new Ticker
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func NewTicker(minDuration time.Duration, maxJitter time.Duration) *Ticker {
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if minDuration < 0 {
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log.WithField("duration", minDuration).Panic("Negative duration")
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}
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if maxJitter < 0 {
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log.WithField("jitter", minDuration).Panic("Negative jitter")
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}
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c := make(chan time.Time, 1)
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ticker := &Ticker{
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C: c,
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stop: make(chan bool),
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MinDuration: minDuration,
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MaxJitter: maxJitter,
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}
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go ticker.loop(c)
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return ticker
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}
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func (t *Ticker) loop(c chan time.Time) {
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tickLoop:
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for {
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time.Sleep(t.calculateDelay())
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// Send best-effort then go back to sleep.
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select {
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case <-t.stop:
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log.Info("Stopping jittered ticker")
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close(c)
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break tickLoop
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case c <- time.Now():
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default:
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}
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}
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}
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func (t *Ticker) calculateDelay() time.Duration {
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jitter := time.Duration(rand.Int63n(int64(t.MaxJitter)))
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delay := t.MinDuration + jitter
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return delay
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}
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// Stop the ticker
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func (t *Ticker) Stop() {
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t.stop <- true
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}
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