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oauth2-proxy/watcher.go
Mike Bland 020a35e85f Remove file watch upon interruption
TestValidatorOverwriteEmailListViaRenameAndReplace was deadlocking on
Windows because, on Windows, fsnotify.Watcher will continue to watch a
renamed file using its new name. On other systems, it appears the watch on
a file is removed after a rename.

The fix is to explicitly remove the watch to ensure the watch is resumed
under the original name.
2015-05-14 07:57:30 -04:00

71 lines
1.8 KiB
Go

// +build go1.3
// +build !plan9,!solaris
package main
import (
"log"
"os"
"path/filepath"
"time"
"gopkg.in/fsnotify.v1"
)
func WaitForReplacement(filename string, op fsnotify.Op,
watcher *fsnotify.Watcher) {
const sleep_interval = 50 * time.Millisecond
// Avoid a race when fsnofity.Remove is preceded by fsnotify.Chmod.
if op&fsnotify.Chmod != 0 {
time.Sleep(sleep_interval)
}
for {
if _, err := os.Stat(filename); err == nil {
if err := watcher.Add(filename); err == nil {
log.Printf("watching resumed for %s", filename)
return
}
}
time.Sleep(sleep_interval)
}
}
func WatchForUpdates(filename string, done <-chan bool, action func()) bool {
filename = filepath.Clean(filename)
watcher, err := fsnotify.NewWatcher()
if err != nil {
log.Fatal("failed to create watcher for ", filename, ": ", err)
}
go func() {
defer watcher.Close()
for {
select {
case _ = <-done:
log.Printf("Shutting down watcher for: %s",
filename)
return
case event := <-watcher.Events:
// On Arch Linux, it appears Chmod events precede Remove events,
// which causes a race between action() and the coming Remove event.
// If the Remove wins, the action() (which calls
// UserMap.LoadAuthenticatedEmailsFile()) crashes when the file
// can't be opened.
if event.Op&(fsnotify.Remove|fsnotify.Rename|fsnotify.Chmod) != 0 {
log.Printf("watching interrupted on event: %s", event)
watcher.Remove(filename)
WaitForReplacement(filename, event.Op, watcher)
}
log.Printf("reloading after event: %s", event)
action()
case err := <-watcher.Errors:
log.Printf("error watching %s: %s", filename, err)
}
}
}()
if err = watcher.Add(filename); err != nil {
log.Fatal("failed to add ", filename, " to watcher: ", err)
}
return true
}