chipmunk/vendor/cloud.google.com/go/internal/retry.go
2017-01-24 18:27:39 -08:00

56 lines
1.7 KiB
Go

// Copyright 2016 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package internal
import (
"fmt"
"time"
gax "github.com/googleapis/gax-go"
"golang.org/x/net/context"
)
// Retry calls the supplied function f repeatedly according to the provided
// backoff parameters. It returns when one of the following occurs:
// When f's first return value is true, Retry immediately returns with f's second
// return value.
// When the provided context is done, Retry returns with ctx.Err().
func Retry(ctx context.Context, bo gax.Backoff, f func() (stop bool, err error)) error {
return retry(ctx, bo, f, gax.Sleep)
}
func retry(ctx context.Context, bo gax.Backoff, f func() (stop bool, err error),
sleep func(context.Context, time.Duration) error) error {
var lastErr error
for {
stop, err := f()
if stop {
return err
}
// Remember the last "real" error from f.
if err != nil && err != context.Canceled && err != context.DeadlineExceeded {
lastErr = err
}
p := bo.Pause()
if cerr := sleep(ctx, p); cerr != nil {
if lastErr != nil {
return fmt.Errorf("%v; last function err: %v", cerr, lastErr)
}
return cerr
}
}
}