99 lines
2.3 KiB
Go
99 lines
2.3 KiB
Go
/*
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Copyright 2016 The Kubernetes 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 watch
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import (
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"log"
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"os"
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"path"
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"path/filepath"
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"strings"
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"github.com/fsnotify/fsnotify"
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)
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// FileWatcher is an interface we use to watch changes in files
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type FileWatcher interface {
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Close() error
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}
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// OSFileWatcher defines a watch over a file
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type OSFileWatcher struct {
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file string
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watcher *fsnotify.Watcher
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// onEvent callback to be invoked after the file being watched changes
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onEvent func()
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}
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// NewFileWatcher creates a new FileWatcher
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func NewFileWatcher(file string, onEvent func()) (FileWatcher, error) {
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fw := OSFileWatcher{
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file: file,
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onEvent: onEvent,
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}
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err := fw.watch()
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return fw, err
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}
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// Close ends the watch
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func (f OSFileWatcher) Close() error {
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return f.watcher.Close()
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}
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// watch creates a fsnotify watcher for a file and create of write events
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func (f *OSFileWatcher) watch() error {
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watcher, err := fsnotify.NewWatcher()
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if err != nil {
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return err
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}
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f.watcher = watcher
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realFile, err := filepath.EvalSymlinks(f.file)
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if err != nil {
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return err
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}
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dir, file := path.Split(f.file)
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go func(file string) {
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for {
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select {
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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 finfo, err := os.Lstat(event.Name); err != nil {
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log.Printf("can not lstat file: %v\n", err)
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} else if finfo.Mode()&os.ModeSymlink != 0 {
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if currentRealFile, err := filepath.EvalSymlinks(f.file); err == nil &&
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currentRealFile != realFile {
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f.onEvent()
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realFile = currentRealFile
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}
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continue
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}
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if strings.HasSuffix(event.Name, file) {
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f.onEvent()
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}
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}
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case err := <-watcher.Errors:
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if err != nil {
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log.Printf("error watching file: %v\n", err)
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}
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}
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}
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}(file)
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return watcher.Add(dir)
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}
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