| nikesh.krishnan | 6dd882b | 2023-03-14 10:02:41 +0530 | [diff] [blame^] | 1 | // Copyright 2016 Michal Witkowski. All Rights Reserved. |
| 2 | // See LICENSE for licensing terms. |
| 3 | |
| 4 | /* |
| 5 | Backoff Helper Utilities |
| 6 | |
| 7 | Implements common backoff features. |
| 8 | */ |
| 9 | package backoffutils |
| 10 | |
| 11 | import ( |
| 12 | "math/rand" |
| 13 | "time" |
| 14 | ) |
| 15 | |
| 16 | // JitterUp adds random jitter to the duration. |
| 17 | // |
| 18 | // This adds or subtracts time from the duration within a given jitter fraction. |
| 19 | // For example for 10s and jitter 0.1, it will return a time within [9s, 11s]) |
| 20 | func JitterUp(duration time.Duration, jitter float64) time.Duration { |
| 21 | multiplier := jitter * (rand.Float64()*2 - 1) |
| 22 | return time.Duration(float64(duration) * (1 + multiplier)) |
| 23 | } |
| 24 | |
| 25 | // ExponentBase2 computes 2^(a-1) where a >= 1. If a is 0, the result is 0. |
| 26 | func ExponentBase2(a uint) uint { |
| 27 | return (1 << a) >> 1 |
| 28 | } |