| // 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 filelock |
| |
| import ( |
| "context" |
| "fmt" |
| "os" |
| "path/filepath" |
| "time" |
| ) |
| |
| import ( |
| "github.com/gofrs/flock" |
| ) |
| |
| func lock( |
| ctx context.Context, |
| filePath string, |
| options ...LockOption, |
| ) (Unlocker, error) { |
| return lockForFunc( |
| ctx, |
| filePath, |
| (*flock.Flock).TryLockContext, |
| options..., |
| ) |
| } |
| |
| func rlock( |
| ctx context.Context, |
| filePath string, |
| options ...LockOption, |
| ) (Unlocker, error) { |
| return lockForFunc( |
| ctx, |
| filePath, |
| (*flock.Flock).TryRLockContext, |
| options..., |
| ) |
| } |
| |
| func lockForFunc( |
| ctx context.Context, |
| filePath string, |
| tryLockContextFunc func(*flock.Flock, context.Context, time.Duration) (bool, error), |
| options ...LockOption, |
| ) (Unlocker, error) { |
| lockOptions := newLockOptions() |
| for _, option := range options { |
| option(lockOptions) |
| } |
| // mkdir is an atomic operation |
| if err := os.MkdirAll(filepath.Dir(filePath), 0o755); err != nil { |
| return nil, err |
| } |
| var cancel context.CancelFunc |
| if lockOptions.timeout != 0 { |
| ctx, cancel = context.WithTimeout(ctx, lockOptions.timeout) |
| defer cancel() |
| } |
| flock := flock.New(filePath) |
| locked, err := tryLockContextFunc(flock, ctx, lockOptions.retryDelay) |
| if err != nil { |
| return nil, fmt.Errorf("could not get file lock %q: %w", filePath, err) |
| } |
| if !locked { |
| return nil, fmt.Errorf("could not lock %q", filePath) |
| } |
| return flock, nil |
| } |
| |
| type lockOptions struct { |
| timeout time.Duration |
| retryDelay time.Duration |
| } |
| |
| func newLockOptions() *lockOptions { |
| return &lockOptions{ |
| timeout: DefaultLockTimeout, |
| retryDelay: DefaultLockRetryDelay, |
| } |
| } |