diff options
Diffstat (limited to 'vendor/cloud.google.com/go/compute/metadata/retry.go')
-rw-r--r-- | vendor/cloud.google.com/go/compute/metadata/retry.go | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/vendor/cloud.google.com/go/compute/metadata/retry.go b/vendor/cloud.google.com/go/compute/metadata/retry.go new file mode 100644 index 0000000000..0f18f3cda1 --- /dev/null +++ b/vendor/cloud.google.com/go/compute/metadata/retry.go @@ -0,0 +1,114 @@ +// Copyright 2021 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 metadata + +import ( + "context" + "io" + "math/rand" + "net/http" + "time" +) + +const ( + maxRetryAttempts = 5 +) + +var ( + syscallRetryable = func(err error) bool { return false } +) + +// defaultBackoff is basically equivalent to gax.Backoff without the need for +// the dependency. +type defaultBackoff struct { + max time.Duration + mul float64 + cur time.Duration +} + +func (b *defaultBackoff) Pause() time.Duration { + d := time.Duration(1 + rand.Int63n(int64(b.cur))) + b.cur = time.Duration(float64(b.cur) * b.mul) + if b.cur > b.max { + b.cur = b.max + } + return d +} + +// sleep is the equivalent of gax.Sleep without the need for the dependency. +func sleep(ctx context.Context, d time.Duration) error { + t := time.NewTimer(d) + select { + case <-ctx.Done(): + t.Stop() + return ctx.Err() + case <-t.C: + return nil + } +} + +func newRetryer() *metadataRetryer { + return &metadataRetryer{bo: &defaultBackoff{ + cur: 100 * time.Millisecond, + max: 30 * time.Second, + mul: 2, + }} +} + +type backoff interface { + Pause() time.Duration +} + +type metadataRetryer struct { + bo backoff + attempts int +} + +func (r *metadataRetryer) Retry(status int, err error) (time.Duration, bool) { + if status == http.StatusOK { + return 0, false + } + retryOk := shouldRetry(status, err) + if !retryOk { + return 0, false + } + if r.attempts == maxRetryAttempts { + return 0, false + } + r.attempts++ + return r.bo.Pause(), true +} + +func shouldRetry(status int, err error) bool { + if 500 <= status && status <= 599 { + return true + } + if err == io.ErrUnexpectedEOF { + return true + } + // Transient network errors should be retried. + if syscallRetryable(err) { + return true + } + if err, ok := err.(interface{ Temporary() bool }); ok { + if err.Temporary() { + return true + } + } + if err, ok := err.(interface{ Unwrap() error }); ok { + return shouldRetry(status, err.Unwrap()) + } + return false +} |