85 lines
2.4 KiB
Go
85 lines
2.4 KiB
Go
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/*
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Copyright 2015 Google Inc. All Rights Reserved.
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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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// This is ia snapshot from github.com/googleapis/gax-go with minor modifications.
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package gax
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import (
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"math/rand"
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"time"
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"golang.org/x/net/context"
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"google.golang.org/grpc"
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"google.golang.org/grpc/codes"
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"log"
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"os"
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)
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var logger *log.Logger = log.New(os.Stderr, "", log.LstdFlags)
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// A user defined call stub.
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type APICall func(context.Context) error
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// scaleDuration returns the product of a and mult.
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func scaleDuration(a time.Duration, mult float64) time.Duration {
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ns := float64(a) * mult
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return time.Duration(ns)
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}
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// invokeWithRetry calls stub using an exponential backoff retry mechanism
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// based on the values provided in callSettings.
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func invokeWithRetry(ctx context.Context, stub APICall, callSettings CallSettings) error {
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retrySettings := callSettings.RetrySettings
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backoffSettings := callSettings.RetrySettings.BackoffSettings
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delay := backoffSettings.DelayTimeoutSettings.Initial
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for {
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// If the deadline is exceeded...
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if ctx.Err() != nil {
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return ctx.Err()
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}
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err := stub(ctx)
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code := grpc.Code(err)
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if code == codes.OK {
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return nil
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}
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if !retrySettings.RetryCodes[code] {
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return err
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}
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// Sleep a random amount up to the current delay
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d := time.Duration(rand.Int63n(int64(delay)))
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delayCtx, _ := context.WithTimeout(ctx, delay)
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logger.Printf("Retryable error: %v, retrying in %v", err, d)
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<-delayCtx.Done()
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delay = scaleDuration(delay, backoffSettings.DelayTimeoutSettings.Multiplier)
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if delay > backoffSettings.DelayTimeoutSettings.Max {
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delay = backoffSettings.DelayTimeoutSettings.Max
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}
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}
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}
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// Invoke calls stub with a child of context modified by the specified options.
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func Invoke(ctx context.Context, stub APICall, opts ...CallOption) error {
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settings := &CallSettings{}
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callOptions(opts).Resolve(settings)
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if len(settings.RetrySettings.RetryCodes) > 0 {
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return invokeWithRetry(ctx, stub, *settings)
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}
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return stub(ctx)
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}
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