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 "context" 34 "time" 35) 36 37// A user defined call stub. 38type APICall func(context.Context, CallSettings) error 39 40// Invoke calls the given APICall, 41// performing retries as specified by opts, if any. 42func Invoke(ctx context.Context, call APICall, opts ...CallOption) error { 43 var settings CallSettings 44 for _, opt := range opts { 45 opt.Resolve(&settings) 46 } 47 return invoke(ctx, call, settings, Sleep) 48} 49 50// Sleep is similar to time.Sleep, but it can be interrupted by ctx.Done() closing. 51// If interrupted, Sleep returns ctx.Err(). 52func Sleep(ctx context.Context, d time.Duration) error { 53 t := time.NewTimer(d) 54 select { 55 case <-ctx.Done(): 56 t.Stop() 57 return ctx.Err() 58 case <-t.C: 59 return nil 60 } 61} 62 63type sleeper func(ctx context.Context, d time.Duration) error 64 65// invoke implements Invoke, taking an additional sleeper argument for testing. 66func invoke(ctx context.Context, call APICall, settings CallSettings, sp sleeper) error { 67 var retryer Retryer 68 for { 69 err := call(ctx, settings) 70 if err == nil { 71 return nil 72 } 73 if settings.Retry == nil { 74 return err 75 } 76 if retryer == nil { 77 if r := settings.Retry(); r != nil { 78 retryer = r 79 } else { 80 return err 81 } 82 } 83 if d, ok := retryer.Retry(err); !ok { 84 return err 85 } else if err = sp(ctx, d); err != nil { 86 return err 87 } 88 } 89} 90