| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 retry |
| |
| import ( |
| "errors" |
| "fmt" |
| "time" |
| |
| "github.com/apache/dubbo-kubernetes/test" |
| ) |
| |
| const ( |
| // DefaultTimeout the default timeout for the entire retry operation |
| DefaultTimeout = time.Second * 30 |
| |
| // DefaultDelay the default delay between successive retry attempts |
| DefaultDelay = time.Millisecond * 10 |
| |
| // DefaultConverge the default converge, requiring something to succeed one time |
| DefaultConverge = 1 |
| ) |
| |
| var defaultConfig = config{ |
| timeout: DefaultTimeout, |
| delay: DefaultDelay, |
| converge: DefaultConverge, |
| } |
| |
| type config struct { |
| error string |
| timeout time.Duration |
| delay time.Duration |
| converge int |
| } |
| |
| // Option for a retry operation. |
| type Option func(cfg *config) |
| |
| // Timeout sets the timeout for the entire retry operation. |
| func Timeout(timeout time.Duration) Option { |
| return func(cfg *config) { |
| cfg.timeout = timeout |
| } |
| } |
| |
| // Delay sets the delay between successive retry attempts. |
| func Delay(delay time.Duration) Option { |
| return func(cfg *config) { |
| cfg.delay = delay |
| } |
| } |
| |
| // Converge sets the number of successes in a row needed to count a success. |
| // This is useful to avoid the case where tests like `coin.Flip() == HEADS` will always |
| // return success due to random variance. |
| func Converge(successes int) Option { |
| return func(cfg *config) { |
| cfg.converge = successes |
| } |
| } |
| |
| // Message defines a more detailed error message to use when failing |
| func Message(errorMessage string) Option { |
| return func(cfg *config) { |
| cfg.error = errorMessage |
| } |
| } |
| |
| // RetriableFunc a function that can be retried. |
| type RetriableFunc func() (result interface{}, completed bool, err error) |
| |
| // UntilSuccess retries the given function until success, timeout, or until the passed-in function returns nil. |
| func UntilSuccess(fn func() error, options ...Option) error { |
| _, e := Do(func() (interface{}, bool, error) { |
| err := fn() |
| if err != nil { |
| return nil, false, err |
| } |
| |
| return nil, true, nil |
| }, options...) |
| |
| return e |
| } |
| |
| // UntilSuccessOrFail calls UntilSuccess, and fails t with Fatalf if it ends up returning an error |
| func UntilSuccessOrFail(t test.Failer, fn func() error, options ...Option) { |
| t.Helper() |
| err := UntilSuccess(fn, options...) |
| if err != nil { |
| t.Fatalf("retry.UntilSuccessOrFail: %v", err) |
| } |
| } |
| |
| var ErrConditionNotMet = errors.New("expected condition not met") |
| |
| // Until retries the given function until it returns true or hits the timeout timeout |
| func Until(fn func() bool, options ...Option) error { |
| return UntilSuccess(func() error { |
| if !fn() { |
| return getErrorMessage(options) |
| } |
| return nil |
| }, options...) |
| } |
| |
| // UntilOrFail calls Until, and fails t with Fatalf if it ends up returning an error |
| func UntilOrFail(t test.Failer, fn func() bool, options ...Option) { |
| t.Helper() |
| err := Until(fn, options...) |
| if err != nil { |
| t.Fatalf("retry.UntilOrFail: %v", err) |
| } |
| } |
| |
| func getErrorMessage(options []Option) error { |
| cfg := defaultConfig |
| for _, option := range options { |
| option(&cfg) |
| } |
| if cfg.error == "" { |
| return ErrConditionNotMet |
| } |
| return errors.New(cfg.error) |
| } |
| |
| // Do retries the given function, until there is a timeout, or until the function indicates that it has completed. |
| func Do(fn RetriableFunc, options ...Option) (interface{}, error) { |
| cfg := defaultConfig |
| for _, option := range options { |
| option(&cfg) |
| } |
| |
| successes := 0 |
| var lasterr error |
| to := time.After(cfg.timeout) |
| for { |
| select { |
| case <-to: |
| return nil, fmt.Errorf("timeout while waiting (last error: %v)", lasterr) |
| default: |
| } |
| |
| result, completed, err := fn() |
| if completed { |
| if err == nil { |
| successes++ |
| } else { |
| successes = 0 |
| } |
| if successes >= cfg.converge { |
| return result, err |
| } |
| |
| // Skip delay if we have a success |
| continue |
| } else { |
| successes = 0 |
| } |
| if err != nil { |
| lasterr = err |
| } |
| |
| <-time.After(cfg.delay) |
| } |
| } |