112 lines
2.3 KiB
Go
112 lines
2.3 KiB
Go
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// Copyright © 2016 Abcum Ltd
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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 hook
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import (
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"context"
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"time"
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)
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const (
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Static Kind = iota
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Backoff
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)
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// Kind specifies the policy type.
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type Kind int
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// Policy represents a retryable function policy.
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type Policy struct {
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// Type is the policy type
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Type Kind
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// Attempts to retry
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Retry int
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// Factor is the backoff rate
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Factor int
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// Sleep is the initial duration to wait before retrying
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Sleep time.Duration
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}
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// New creates a new static retryable policy, which retries
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// after the duration of 'sleep', until the number of retries
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// has been reached.
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func NewStatic(retry int, sleep time.Duration) *Policy {
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return &Policy{
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Type: Static,
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Retry: retry,
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Sleep: sleep,
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}
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}
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// New creates a new backoff retryable policy, which increases
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// the delay between subsequent retries by the secified factor,
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// until the number of retries has been reached.
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func NewBackoff(retry, factor int, sleep time.Duration) *Policy {
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return &Policy{
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Type: Backoff,
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Retry: retry,
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Sleep: sleep,
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Factor: factor,
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}
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}
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// Run executes a function until:
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// 1. A nil error is returned,
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// 2. The max number of retries has been reached,
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// 3. The specified context has been cancelled or timedout.
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func (p *Policy) Run(ctx context.Context, fnc func() error) error {
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c := make(chan error, 1)
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go func() { c <- p.run(ctx, fnc) }()
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select {
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case <-ctx.Done():
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return ctx.Err()
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case err := <-c:
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return err
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}
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}
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func (p *Policy) run(ctx context.Context, fnc func() error) error {
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select {
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case <-ctx.Done():
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return ctx.Err()
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default:
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if err := fnc(); err != nil {
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if p.Retry > 0 {
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p.sleep()
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p.Retry = p.Retry - 1
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return p.run(ctx, fnc)
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}
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}
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}
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return nil
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}
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func (p *Policy) sleep() {
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time.Sleep(p.Sleep)
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if p.Type == Backoff {
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p.Sleep = p.Sleep * time.Duration(p.Factor)
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}
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}
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