forked from TrueCloudLab/distribution
86 lines
2.5 KiB
Go
86 lines
2.5 KiB
Go
|
// Copyright 2016 Google LLC
|
||
|
|
//
|
||
|
|
// 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 (
|
||
|
|
"context"
|
||
|
|
"fmt"
|
||
|
|
"time"
|
||
|
|
|
||
|
|
gax "github.com/googleapis/gax-go/v2"
|
||
|
|
"google.golang.org/grpc/status"
|
||
|
|
)
|
||
|
|
|
||
|
|
// 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 an error that
|
||
|
|
// includes both ctx.Error() and the last error returned by f.
|
||
|
|
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 ctxErr := sleep(ctx, p); ctxErr != nil {
|
||
|
|
if lastErr != nil {
|
||
|
|
return wrappedCallErr{ctxErr: ctxErr, wrappedErr: lastErr}
|
||
|
|
}
|
||
|
|
return ctxErr
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Use this error type to return an error which allows introspection of both
|
||
|
|
// the context error and the error from the service.
|
||
|
|
type wrappedCallErr struct {
|
||
|
|
ctxErr error
|
||
|
|
wrappedErr error
|
||
|
|
}
|
||
|
|
|
||
|
|
func (e wrappedCallErr) Error() string {
|
||
|
|
return fmt.Sprintf("retry failed with %v; last error: %v", e.ctxErr, e.wrappedErr)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (e wrappedCallErr) Unwrap() error {
|
||
|
|
return e.wrappedErr
|
||
|
|
}
|
||
|
|
|
||
|
|
// Is allows errors.Is to match the error from the call as well as context
|
||
|
|
// sentinel errors.
|
||
|
|
func (e wrappedCallErr) Is(err error) bool {
|
||
|
|
return e.ctxErr == err || e.wrappedErr == err
|
||
|
|
}
|
||
|
|
|
||
|
|
// GRPCStatus allows the wrapped error to be used with status.FromError.
|
||
|
|
func (e wrappedCallErr) GRPCStatus() *status.Status {
|
||
|
|
if s, ok := status.FromError(e.wrappedErr); ok {
|
||
|
|
return s
|
||
|
|
}
|
||
|
|
return nil
|
||
|
|
}
|