vendor/github.com/googleapis/gax-go/v2/invoke.go

   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
  30 package gax
  31
  32 import (
  33         "context"
  34         "strings"
  35         "time"
  36 )
  37
  38 // APICall is a user defined call stub.
  39 type APICall func(context.Context, CallSettings) error
  40
  41 // Invoke calls the given APICall,
  42 // performing retries as specified by opts, if any.
  43 func 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().
  53 func 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
  64 type sleeper func(ctx context.Context, d time.Duration) error
  65
  66 // invoke implements Invoke, taking an additional sleeper argument for testing.
  67 func 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                 // Never retry permanent certificate errors. (e.x. if ca-certificates
  78                 // are not installed). We should only make very few, targeted
  79                 // exceptions: many (other) status=Unavailable should be retried, such
  80                 // as if there's a network hiccup, or the internet goes out for a
  81                 // minute. This is also why here we are doing string parsing instead of
  82                 // simply making Unavailable a non-retried code elsewhere.
  83                 if strings.Contains(err.Error(), "x509: certificate signed by unknown authority") {
  84                         return err
  85                 }
  86                 if retryer == nil {
  87                         if r := settings.Retry(); r != nil {
  88                                 retryer = r
  89                         } else {
  90                                 return err
  91                         }
  92                 }
  93                 if d, ok := retryer.Retry(err); !ok {
  94                         return err
  95                 } else if err = sp(ctx, d); err != nil {
  96                         return err
  97                 }
  98         }
  99 }