diff options
Diffstat (limited to 'vendor/google.golang.org/api/gensupport/backoff.go')
-rw-r--r-- | vendor/google.golang.org/api/gensupport/backoff.go | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/vendor/google.golang.org/api/gensupport/backoff.go b/vendor/google.golang.org/api/gensupport/backoff.go new file mode 100644 index 000000000..94b7789ee --- /dev/null +++ b/vendor/google.golang.org/api/gensupport/backoff.go @@ -0,0 +1,51 @@ +// Copyright 2016 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package gensupport + +import ( + "math/rand" + "time" +) + +// BackoffStrategy defines the set of functions that a backoff-er must +// implement. +type BackoffStrategy interface { + // Pause returns the duration of the next pause and true if the operation should be + // retried, or false if no further retries should be attempted. + Pause() (time.Duration, bool) + + // Reset restores the strategy to its initial state. + Reset() +} + +// ExponentialBackoff performs exponential backoff as per https://en.wikipedia.org/wiki/Exponential_backoff. +// The initial pause time is given by Base. +// Once the total pause time exceeds Max, Pause will indicate no further retries. +type ExponentialBackoff struct { + Base time.Duration + Max time.Duration + total time.Duration + n uint +} + +// Pause returns the amount of time the caller should wait. +func (eb *ExponentialBackoff) Pause() (time.Duration, bool) { + if eb.total > eb.Max { + return 0, false + } + + // The next pause is selected from randomly from [0, 2^n * Base). + d := time.Duration(rand.Int63n((1 << eb.n) * int64(eb.Base))) + eb.total += d + eb.n++ + return d, true +} + +// Reset resets the backoff strategy such that the next Pause call will begin +// counting from the start. It is not safe to call concurrently with Pause. +func (eb *ExponentialBackoff) Reset() { + eb.n = 0 + eb.total = 0 +} |