c814ba26e9
* Changed thrift function call wrapper to be more explicitly named and to perform more safety checks. * Moved Jitter function from realis to retry. * API code is now more uniform and follows a certain template. * Lock added whenever a thrift call is made or when a modification is done to the connection. Note that calling ReestablishConn externally may result in some race conditions. We will move to make this function private in the near future.
82 lines
2.3 KiB
Go
82 lines
2.3 KiB
Go
/*
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Copyright 2014 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package realis
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import (
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"errors"
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"time"
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"math/rand"
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)
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// Jitter returns a time.Duration between duration and duration + maxFactor *
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// duration.
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//
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// This allows clients to avoid converging on periodic behavior. If maxFactor
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// is 0.0, a suggested default value will be chosen.
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func Jitter(duration time.Duration, maxFactor float64) time.Duration {
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if maxFactor <= 0.0 {
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maxFactor = 1.0
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}
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wait := duration + time.Duration(rand.Float64()*maxFactor*float64(duration))
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return wait
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}
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// ConditionFunc returns true if the condition is satisfied, or an error
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// if the loop should be aborted.
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type ConditionFunc func() (done bool, err error)
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// Modified version of the Kubernetes exponential-backoff code.
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// ExponentialBackoff repeats a condition check with exponential backoff.
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//
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// It checks the condition up to Steps times, increasing the wait by multiplying
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// the previous duration by Factor.
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//
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// If Jitter is greater than zero, a random amount of each duration is added
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// (between duration and duration*(1+jitter)).
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//
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// If the condition never returns true, ErrWaitTimeout is returned. All other
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// errors terminate immediately.
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func ExponentialBackoff(backoff Backoff, condition ConditionFunc) error {
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duration := backoff.Duration
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for i := 0; i < backoff.Steps; i++ {
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if i != 0 {
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adjusted := duration
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if backoff.Jitter > 0.0 {
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adjusted = Jitter(duration, backoff.Jitter)
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}
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time.Sleep(adjusted)
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duration = time.Duration(float64(duration) * backoff.Factor)
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}
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ok, err := condition()
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// If the function executed says it succeeded, stop retrying
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if ok {
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return nil
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}
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// Stop retrying if the error is NOT temporary.
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if err != nil {
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if !IsTemporary(err) {
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return err
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}
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}
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}
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return NewTimeoutError(errors.New("Timed out while retrying"))
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}
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