1// Copyright 2016, Google Inc. 2// All rights reserved. 3// 4// Redistribution and use in source and binary forms, with or without 5// modification, are permitted provided that the following conditions are 6// met: 7// 8// * Redistributions of source code must retain the above copyright 9// notice, this list of conditions and the following disclaimer. 10// * Redistributions in binary form must reproduce the above 11// copyright notice, this list of conditions and the following disclaimer 12// in the documentation and/or other materials provided with the 13// distribution. 14// * Neither the name of Google Inc. nor the names of its 15// contributors may be used to endorse or promote products derived from 16// this software without specific prior written permission. 17// 18// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30package gax 31 32import ( 33 "time" 34 35 "golang.org/x/net/context" 36) 37 38// A user defined call stub. 39type APICall func(context.Context, CallSettings) error 40 41// Invoke calls the given APICall, 42// performing retries as specified by opts, if any. 43func Invoke(ctx context.Context, call APICall, opts ...CallOption) error { 44 var settings CallSettings 45 for _, opt := range opts { 46 opt.Resolve(&settings) 47 } 48 return invoke(ctx, call, settings, Sleep) 49} 50 51// Sleep is similar to time.Sleep, but it can be interrupted by ctx.Done() closing. 52// If interrupted, Sleep returns ctx.Err(). 53func Sleep(ctx context.Context, d time.Duration) error { 54 t := time.NewTimer(d) 55 select { 56 case <-ctx.Done(): 57 t.Stop() 58 return ctx.Err() 59 case <-t.C: 60 return nil 61 } 62} 63 64type sleeper func(ctx context.Context, d time.Duration) error 65 66// invoke implements Invoke, taking an additional sleeper argument for testing. 67func invoke(ctx context.Context, call APICall, settings CallSettings, sp sleeper) error { 68 var retryer Retryer 69 for { 70 err := call(ctx, settings) 71 if err == nil { 72 return nil 73 } 74 if settings.Retry == nil { 75 return err 76 } 77 if retryer == nil { 78 if r := settings.Retry(); r != nil { 79 retryer = r 80 } else { 81 return err 82 } 83 } 84 if d, ok := retryer.Retry(err); !ok { 85 return err 86 } else if err = sp(ctx, d); err != nil { 87 return err 88 } 89 } 90} 91