mirror of https://github.com/dapr/kit.git
76 lines
2.0 KiB
Go
76 lines
2.0 KiB
Go
/*
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Copyright 2022 The Dapr Authors
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package fswatcher
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import (
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"context"
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"fmt"
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"strings"
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"time"
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"github.com/fsnotify/fsnotify"
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)
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// Watch for changes to a directory on the filesystem and sends a notification to eventCh every time a file in the folder is changed.
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// Although it's possible to watch for individual files, that's not recommended; watch for the file's parent folder instead.
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// Note that changes are batched for 0.5 seconds before notifications are sent
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func Watch(ctx context.Context, dir string, eventCh chan<- struct{}) error {
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watcher, err := fsnotify.NewWatcher()
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if err != nil {
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return fmt.Errorf("failed to create watcher: %w", err)
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}
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defer watcher.Close()
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err = watcher.Add(dir)
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if err != nil {
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return fmt.Errorf("watcher error: %w", err)
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}
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batchCh := make(chan struct{}, 1)
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defer close(batchCh)
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for {
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select {
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// Watch for events
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case event := <-watcher.Events:
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if event.Op&fsnotify.Create == fsnotify.Create ||
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event.Op&fsnotify.Write == fsnotify.Write {
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if strings.Contains(event.Name, dir) {
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// Batch the change
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select {
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case batchCh <- struct{}{}:
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go func() {
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time.Sleep(500 * time.Millisecond)
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<-batchCh
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eventCh <- struct{}{}
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}()
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default:
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// There's already a change in the batch - nop
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}
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}
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}
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// Abort in case of errors
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case err = <-watcher.Errors:
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return fmt.Errorf("watcher listen error: %w", err)
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// Stop on context canceled
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case <-ctx.Done():
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return ctx.Err()
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}
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}
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}
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