feat: optimize retry #284
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,134 @@ | ||
| /* | ||
| * Licensed to the Apache Software Foundation (ASF) under one or more | ||
| * contributor license agreements. See the NOTICE file distributed with | ||
| * this work for additional information regarding copyright ownership. | ||
| * The ASF licenses this file to You 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. | ||
| */ | ||
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| package backoff | ||
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| import ( | ||
| "context" | ||
| "flag" | ||
| "fmt" | ||
| "math/rand" | ||
| "time" | ||
| ) | ||
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| // Config configures a Backoff | ||
| type Config struct { | ||
| MinBackoff time.Duration `yaml:"min_period"` // start backoff at this level | ||
| MaxBackoff time.Duration `yaml:"max_period"` // increase exponentially to this level | ||
| MaxRetries int `yaml:"max_retries"` // give up after this many; zero means infinite retries | ||
| } | ||
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| // RegisterFlagsWithPrefix for Config. | ||
| func (cfg *Config) RegisterFlagsWithPrefix(prefix string, f *flag.FlagSet) { | ||
| f.DurationVar(&cfg.MinBackoff, prefix+".backoff-min-period", 100*time.Millisecond, "Minimum delay when backing off.") | ||
| f.DurationVar(&cfg.MaxBackoff, prefix+".backoff-max-period", 10*time.Second, "Maximum delay when backing off.") | ||
| f.IntVar(&cfg.MaxRetries, prefix+".backoff-retries", 10, "Number of times to backoff and retry before failing.") | ||
| } | ||
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| // Backoff implements exponential backoff with randomized wait times | ||
| type Backoff struct { | ||
| cfg Config | ||
| ctx context.Context | ||
| numRetries int | ||
| nextDelayMin time.Duration | ||
| nextDelayMax time.Duration | ||
| } | ||
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| // New creates a Backoff object. Pass a Context that can also terminate the operation. | ||
| func New(ctx context.Context, cfg Config) *Backoff { | ||
| return &Backoff{ | ||
| cfg: cfg, | ||
| ctx: ctx, | ||
| nextDelayMin: cfg.MinBackoff, | ||
| nextDelayMax: doubleDuration(cfg.MinBackoff, cfg.MaxBackoff), | ||
| } | ||
| } | ||
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| // Reset the Backoff back to its initial condition | ||
| func (b *Backoff) Reset() { | ||
| b.numRetries = 0 | ||
| b.nextDelayMin = b.cfg.MinBackoff | ||
| b.nextDelayMax = doubleDuration(b.cfg.MinBackoff, b.cfg.MaxBackoff) | ||
| } | ||
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| // Ongoing returns true if caller should keep going | ||
| func (b *Backoff) Ongoing() bool { | ||
| // Stop if Context has errored or max retry count is exceeded | ||
| return b.ctx.Err() == nil && (b.cfg.MaxRetries == 0 || b.numRetries < b.cfg.MaxRetries) | ||
| } | ||
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| // Err returns the reason for terminating the backoff, or nil if it didn't terminate | ||
| func (b *Backoff) Err() error { | ||
| if b.ctx.Err() != nil { | ||
| return b.ctx.Err() | ||
| } | ||
| if b.cfg.MaxRetries != 0 && b.numRetries >= b.cfg.MaxRetries { | ||
| return fmt.Errorf("terminated after %d retries", b.numRetries) | ||
| } | ||
| return nil | ||
| } | ||
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| // NumRetries returns the number of retries so far | ||
| func (b *Backoff) NumRetries() int { | ||
| return b.numRetries | ||
| } | ||
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| // Wait sleeps for the backoff time then increases the retry count and backoff time | ||
| // Returns immediately if Context is terminated | ||
| func (b *Backoff) Wait() { | ||
| // Increase the number of retries and get the next delay | ||
| sleepTime := b.NextDelay() | ||
|
There was a problem hiding this comment. This statement can be put into the if range There was a problem hiding this comment.
感觉是个优化项，不是问题，比如： if b.Ongoing() { There was a problem hiding this comment. 你这个不太好。目前这个实现已经很简洁了 |
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| if b.Ongoing() { | ||
| select { | ||
| case <-b.ctx.Done(): | ||
| case <-time.After(sleepTime): | ||
| } | ||
| } | ||
| } | ||
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| func (b *Backoff) NextDelay() time.Duration { | ||
| b.numRetries++ | ||
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| // Handle the edge case where the min and max have the same value | ||
| // (or due to some misconfig max is < min) | ||
| if b.nextDelayMin >= b.nextDelayMax { | ||
| return b.nextDelayMin | ||
| } | ||
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| // Add a jitter within the next exponential backoff range | ||
| sleepTime := b.nextDelayMin + time.Duration(rand.Int63n(int64(b.nextDelayMax-b.nextDelayMin))) | ||
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| // Apply the exponential backoff to calculate the next jitter | ||
| // range, unless we've already reached the max | ||
| if b.nextDelayMax < b.cfg.MaxBackoff { | ||
| b.nextDelayMin = doubleDuration(b.nextDelayMin, b.cfg.MaxBackoff) | ||
| b.nextDelayMax = doubleDuration(b.nextDelayMax, b.cfg.MaxBackoff) | ||
| } | ||
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| return sleepTime | ||
| } | ||
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| func doubleDuration(value time.Duration, max time.Duration) time.Duration { | ||
| value = value * 2 | ||
|
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| if value <= max { | ||
| return value | ||
| } | ||
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| return max | ||
| } | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,120 @@ | ||
| /* | ||
| * Licensed to the Apache Software Foundation (ASF) under one or more | ||
| * contributor license agreements. See the NOTICE file distributed with | ||
| * this work for additional information regarding copyright ownership. | ||
| * The ASF licenses this file to You 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. | ||
| */ | ||
|
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| package backoff | ||
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| import ( | ||
| "context" | ||
| "testing" | ||
| "time" | ||
| ) | ||
|
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| func TestBackoff_NextDelay(t *testing.T) { | ||
| t.Parallel() | ||
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| tests := map[string]struct { | ||
| minBackoff time.Duration | ||
| maxBackoff time.Duration | ||
| expectedRanges [][]time.Duration | ||
| }{ | ||
| "exponential backoff with jitter honoring min and max": { | ||
| minBackoff: 100 * time.Millisecond, | ||
| maxBackoff: 10 * time.Second, | ||
| expectedRanges: [][]time.Duration{ | ||
| {100 * time.Millisecond, 200 * time.Millisecond}, | ||
| {200 * time.Millisecond, 400 * time.Millisecond}, | ||
| {400 * time.Millisecond, 800 * time.Millisecond}, | ||
| {800 * time.Millisecond, 1600 * time.Millisecond}, | ||
| {1600 * time.Millisecond, 3200 * time.Millisecond}, | ||
| {3200 * time.Millisecond, 6400 * time.Millisecond}, | ||
| {6400 * time.Millisecond, 10000 * time.Millisecond}, | ||
| {6400 * time.Millisecond, 10000 * time.Millisecond}, | ||
| }, | ||
| }, | ||
| "exponential backoff with max equal to the end of a range": { | ||
| minBackoff: 100 * time.Millisecond, | ||
| maxBackoff: 800 * time.Millisecond, | ||
| expectedRanges: [][]time.Duration{ | ||
| {100 * time.Millisecond, 200 * time.Millisecond}, | ||
| {200 * time.Millisecond, 400 * time.Millisecond}, | ||
| {400 * time.Millisecond, 800 * time.Millisecond}, | ||
| {400 * time.Millisecond, 800 * time.Millisecond}, | ||
| }, | ||
| }, | ||
| "exponential backoff with max equal to the end of a range + 1": { | ||
| minBackoff: 100 * time.Millisecond, | ||
| maxBackoff: 801 * time.Millisecond, | ||
| expectedRanges: [][]time.Duration{ | ||
| {100 * time.Millisecond, 200 * time.Millisecond}, | ||
| {200 * time.Millisecond, 400 * time.Millisecond}, | ||
| {400 * time.Millisecond, 800 * time.Millisecond}, | ||
| {800 * time.Millisecond, 801 * time.Millisecond}, | ||
| {800 * time.Millisecond, 801 * time.Millisecond}, | ||
| }, | ||
| }, | ||
| "exponential backoff with max equal to the end of a range - 1": { | ||
| minBackoff: 100 * time.Millisecond, | ||
| maxBackoff: 799 * time.Millisecond, | ||
| expectedRanges: [][]time.Duration{ | ||
| {100 * time.Millisecond, 200 * time.Millisecond}, | ||
| {200 * time.Millisecond, 400 * time.Millisecond}, | ||
| {400 * time.Millisecond, 799 * time.Millisecond}, | ||
| {400 * time.Millisecond, 799 * time.Millisecond}, | ||
| }, | ||
| }, | ||
| "min backoff is equal to max": { | ||
| minBackoff: 100 * time.Millisecond, | ||
| maxBackoff: 100 * time.Millisecond, | ||
| expectedRanges: [][]time.Duration{ | ||
| {100 * time.Millisecond, 100 * time.Millisecond}, | ||
| {100 * time.Millisecond, 100 * time.Millisecond}, | ||
| {100 * time.Millisecond, 100 * time.Millisecond}, | ||
| }, | ||
| }, | ||
| "min backoff is greater then max": { | ||
| minBackoff: 200 * time.Millisecond, | ||
| maxBackoff: 100 * time.Millisecond, | ||
| expectedRanges: [][]time.Duration{ | ||
| {200 * time.Millisecond, 200 * time.Millisecond}, | ||
| {200 * time.Millisecond, 200 * time.Millisecond}, | ||
| {200 * time.Millisecond, 200 * time.Millisecond}, | ||
| }, | ||
| }, | ||
| } | ||
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| for testName, testData := range tests { | ||
| testData := testData | ||
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| t.Run(testName, func(t *testing.T) { | ||
| t.Parallel() | ||
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| b := New(context.Background(), Config{ | ||
| MinBackoff: testData.minBackoff, | ||
| MaxBackoff: testData.maxBackoff, | ||
| MaxRetries: len(testData.expectedRanges), | ||
| }) | ||
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| for _, expectedRange := range testData.expectedRanges { | ||
| delay := b.NextDelay() | ||
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| if delay < expectedRange[0] || delay > expectedRange[1] { | ||
| t.Errorf("%d expected to be within %d and %d", delay, expectedRange[0], expectedRange[1]) | ||
| } | ||
| } | ||
| }) | ||
| } | ||
| } |
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这个log级别是不是应该提升为 Error 级别。另外这个log和115行的log感觉是重复的，保留一个应该就可以了。