mirror of https://github.com/hashicorp/consul
76 lines
1.8 KiB
Go
76 lines
1.8 KiB
Go
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package utils
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import (
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"context"
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"time"
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)
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// NOTE: copied from github.com/hashicorp/consul/lib/retry to avoid a heavy dependency
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// NOTE2: Jitter was removed
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// Waiter records the number of failures and performs exponential backoff when
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// when there are consecutive failures.
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type Waiter struct {
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// MinFailures before exponential backoff starts. Any failures before
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// MinFailures is reached will wait MinWait time.
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MinFailures uint
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// MinWait time. Returned after the first failure.
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MinWait time.Duration
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// MaxWait time.
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MaxWait time.Duration
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// Factor is the multiplier to use when calculating the delay. Defaults to
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// 1 second.
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Factor time.Duration
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failures uint
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}
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// delay calculates the time to wait based on the number of failures
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func (w *Waiter) delay() time.Duration {
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if w.failures <= w.MinFailures {
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return w.MinWait
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}
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factor := w.Factor
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if factor == 0 {
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factor = time.Second
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}
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shift := w.failures - w.MinFailures - 1
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waitTime := w.MaxWait
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if shift < 31 {
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waitTime = (1 << shift) * factor
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}
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if w.MaxWait != 0 && waitTime > w.MaxWait {
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waitTime = w.MaxWait
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}
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if waitTime < w.MinWait {
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return w.MinWait
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}
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return waitTime
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}
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// Reset the failure count to 0.
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func (w *Waiter) Reset() {
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w.failures = 0
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}
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// Failures returns the count of consecutive failures.
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func (w *Waiter) Failures() int {
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return int(w.failures)
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}
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// Wait increase the number of failures by one, and then blocks until the context
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// is cancelled, or until the wait time is reached.
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// The wait time increases exponentially as the number of failures increases.
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// Wait will return ctx.Err() if the context is cancelled.
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func (w *Waiter) Wait(ctx context.Context) error {
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w.failures++
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timer := time.NewTimer(w.delay())
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select {
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case <-ctx.Done():
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timer.Stop()
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return ctx.Err()
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case <-timer.C:
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return nil
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}
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}
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