forked from TrueCloudLab/distribution
85 lines
2.5 KiB
Go
85 lines
2.5 KiB
Go
// Copyright 2016 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package internal
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import (
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"context"
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"fmt"
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"time"
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gax "github.com/googleapis/gax-go/v2"
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"google.golang.org/grpc/status"
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)
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// Retry calls the supplied function f repeatedly according to the provided
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// backoff parameters. It returns when one of the following occurs:
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// When f's first return value is true, Retry immediately returns with f's second
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// return value.
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// When the provided context is done, Retry returns with an error that
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// includes both ctx.Error() and the last error returned by f.
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func Retry(ctx context.Context, bo gax.Backoff, f func() (stop bool, err error)) error {
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return retry(ctx, bo, f, gax.Sleep)
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}
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func retry(ctx context.Context, bo gax.Backoff, f func() (stop bool, err error),
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sleep func(context.Context, time.Duration) error) error {
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var lastErr error
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for {
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stop, err := f()
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if stop {
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return err
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}
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// Remember the last "real" error from f.
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if err != nil && err != context.Canceled && err != context.DeadlineExceeded {
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lastErr = err
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}
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p := bo.Pause()
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if ctxErr := sleep(ctx, p); ctxErr != nil {
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if lastErr != nil {
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return wrappedCallErr{ctxErr: ctxErr, wrappedErr: lastErr}
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}
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return ctxErr
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}
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}
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}
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// Use this error type to return an error which allows introspection of both
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// the context error and the error from the service.
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type wrappedCallErr struct {
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ctxErr error
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wrappedErr error
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}
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func (e wrappedCallErr) Error() string {
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return fmt.Sprintf("retry failed with %v; last error: %v", e.ctxErr, e.wrappedErr)
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}
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func (e wrappedCallErr) Unwrap() error {
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return e.wrappedErr
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}
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// Is allows errors.Is to match the error from the call as well as context
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// sentinel errors.
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func (e wrappedCallErr) Is(err error) bool {
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return e.ctxErr == err || e.wrappedErr == err
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}
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// GRPCStatus allows the wrapped error to be used with status.FromError.
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func (e wrappedCallErr) GRPCStatus() *status.Status {
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if s, ok := status.FromError(e.wrappedErr); ok {
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return s
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}
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return nil
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}
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