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91 lines
2.8 KiB
91 lines
2.8 KiB
8 years ago
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// Copyright 2016, Google Inc.
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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package gax
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import (
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"time"
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"golang.org/x/net/context"
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)
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// A user defined call stub.
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type APICall func(context.Context, CallSettings) error
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// Invoke calls the given APICall,
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// performing retries as specified by opts, if any.
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func Invoke(ctx context.Context, call APICall, opts ...CallOption) error {
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var settings CallSettings
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for _, opt := range opts {
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opt.Resolve(&settings)
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}
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return invoke(ctx, call, settings, Sleep)
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}
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// Sleep is similar to time.Sleep, but it can be interrupted by ctx.Done() closing.
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// If interrupted, Sleep returns ctx.Err().
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func Sleep(ctx context.Context, d time.Duration) error {
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t := time.NewTimer(d)
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select {
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case <-ctx.Done():
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t.Stop()
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return ctx.Err()
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case <-t.C:
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return nil
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}
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}
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type sleeper func(ctx context.Context, d time.Duration) error
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// invoke implements Invoke, taking an additional sleeper argument for testing.
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func invoke(ctx context.Context, call APICall, settings CallSettings, sp sleeper) error {
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var retryer Retryer
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for {
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err := call(ctx, settings)
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if err == nil {
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return nil
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}
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if settings.Retry == nil {
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return err
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}
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if retryer == nil {
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if r := settings.Retry(); r != nil {
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retryer = r
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} else {
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return err
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}
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}
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if d, ok := retryer.Retry(err); !ok {
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return err
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} else if err = sp(ctx, d); err != nil {
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return err
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}
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}
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}
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