| // Copyright 2018, OpenCensus Authors |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package ocagent |
| |
| import ( |
| "math/rand" |
| "time" |
| ) |
| |
| var randSrc = rand.New(rand.NewSource(time.Now().UnixNano())) |
| |
| // retries function fn upto n times, if fn returns an error lest it returns nil early. |
| // It applies exponential backoff in units of (1<<n) + jitter microsends. |
| func nTriesWithExponentialBackoff(nTries int64, timeBaseUnit time.Duration, fn func() error) (err error) { |
| for i := int64(0); i < nTries; i++ { |
| err = fn() |
| if err == nil { |
| return nil |
| } |
| // Backoff for a time period with a pseudo-random jitter |
| jitter := time.Duration(randSrc.Float64()*100) * time.Microsecond |
| ts := jitter + ((1 << uint64(i)) * timeBaseUnit) |
| <-time.After(ts) |
| } |
| return err |
| } |
