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