fd26e617b3
Since they're not types common to all the services but belongs to the configstore. Next step will be to make them local to the configstore and not directly used by other services since these types are also stored.
113 lines
3.5 KiB
Go
113 lines
3.5 KiB
Go
// Copyright 2019 Sorint.lab
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//
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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package util
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import (
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"context"
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"errors"
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"math/rand"
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"time"
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)
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// DefaultRetry is the recommended retry for a conflict where multiple clients
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// are making changes to the same resource.
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var DefaultRetry = Backoff{
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Steps: 5,
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Duration: 10 * time.Millisecond,
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Factor: 1.0,
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Jitter: 0.1,
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}
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// DefaultBackoff is the recommended backoff for a conflict where a client
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// may be attempting to make an unrelated modification to a resource under
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// active management by one or more controllers.
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var DefaultBackoff = Backoff{
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Steps: 4,
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Duration: 10 * time.Millisecond,
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Factor: 5.0,
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Jitter: 0.1,
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}
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// DefaultBackoff is the recommended backoff for a conflict where a client
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// may be attempting to make an unrelated modification to a resource under
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// active management by one or more controllers.
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var FetchFileBackoff = Backoff{
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Steps: 4,
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Duration: 500 * time.Millisecond,
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Factor: 2.0,
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Jitter: 0.1,
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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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// ErrWaitTimeout is returned when the condition exited without success.
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var ErrWaitTimeout = errors.New("timed out waiting for the condition")
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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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// Backoff holds parameters applied to a Backoff function.
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type Backoff struct {
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Duration time.Duration // the base duration
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Factor float64 // Duration is multiplied by factor each iteration
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Jitter float64 // The amount of jitter applied each iteration
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Steps int // Exit with error after this many steps
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}
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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(ctx context.Context, 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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sleepCh := time.NewTimer(adjusted).C
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select {
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case <-ctx.Done():
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return nil
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case <-sleepCh:
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}
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duration = time.Duration(float64(duration) * backoff.Factor)
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}
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if ok, err := condition(); err != nil || ok {
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return err
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}
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}
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return ErrWaitTimeout
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}
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