forked from TrueCloudLab/distribution
67 lines
2.1 KiB
Go
67 lines
2.1 KiB
Go
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// Package backoff implements backoff algorithms for retrying operations.
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//
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// Use Retry function for retrying operations that may fail.
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// If Retry does not meet your needs,
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// copy/paste the function into your project and modify as you wish.
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//
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// There is also Ticker type similar to time.Ticker.
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// You can use it if you need to work with channels.
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//
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// See Examples section below for usage examples.
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package backoff
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import "time"
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// BackOff is a backoff policy for retrying an operation.
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type BackOff interface {
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// NextBackOff returns the duration to wait before retrying the operation,
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// or backoff. Stop to indicate that no more retries should be made.
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//
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// Example usage:
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//
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// duration := backoff.NextBackOff();
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// if (duration == backoff.Stop) {
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// // Do not retry operation.
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// } else {
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// // Sleep for duration and retry operation.
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// }
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//
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NextBackOff() time.Duration
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// Reset to initial state.
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Reset()
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}
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// Stop indicates that no more retries should be made for use in NextBackOff().
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const Stop time.Duration = -1
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// ZeroBackOff is a fixed backoff policy whose backoff time is always zero,
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// meaning that the operation is retried immediately without waiting, indefinitely.
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type ZeroBackOff struct{}
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func (b *ZeroBackOff) Reset() {}
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func (b *ZeroBackOff) NextBackOff() time.Duration { return 0 }
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// StopBackOff is a fixed backoff policy that always returns backoff.Stop for
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// NextBackOff(), meaning that the operation should never be retried.
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type StopBackOff struct{}
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func (b *StopBackOff) Reset() {}
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func (b *StopBackOff) NextBackOff() time.Duration { return Stop }
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// ConstantBackOff is a backoff policy that always returns the same backoff delay.
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// This is in contrast to an exponential backoff policy,
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// which returns a delay that grows longer as you call NextBackOff() over and over again.
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type ConstantBackOff struct {
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Interval time.Duration
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}
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func (b *ConstantBackOff) Reset() {}
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func (b *ConstantBackOff) NextBackOff() time.Duration { return b.Interval }
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func NewConstantBackOff(d time.Duration) *ConstantBackOff {
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return &ConstantBackOff{Interval: d}
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}
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