git.iko.soy/typeable/oauth2-proxy
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typeable/oauth2-proxy/watcher.go
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1// +build go1.3,!plan9,!solaris
3package main
5import (
6 "os"
7 "path/filepath"
8 "time"
10 "github.com/pusher/oauth2_proxy/pkg/logger"
11 fsnotify "gopkg.in/fsnotify/fsnotify.v1"
14// WaitForReplacement waits for a file to exist on disk and then starts a watch
15// for the file
16func WaitForReplacement(filename string, op fsnotify.Op,
17 watcher *fsnotify.Watcher) {
18 const sleepInterval = 50 * time.Millisecond
20 // Avoid a race when fsnofity.Remove is preceded by fsnotify.Chmod.
21 if op&fsnotify.Chmod != 0 {
22 time.Sleep(sleepInterval)
23 }
24 for {
25 if _, err := os.Stat(filename); err == nil {
26 if err := watcher.Add(filename); err == nil {
27 logger.Printf("watching resumed for %s", filename)
28 return
29 }
30 }
31 time.Sleep(sleepInterval)
32 }
35// WatchForUpdates performs an action every time a file on disk is updated
36func WatchForUpdates(filename string, done <-chan bool, action func()) {
37 filename = filepath.Clean(filename)
38 watcher, err := fsnotify.NewWatcher()
39 if err != nil {
40 logger.Fatal("failed to create watcher for ", filename, ": ", err)
41 }
42 go func() {
43 defer watcher.Close()
44 for {
45 select {
46 case _ = <-done:
47 logger.Printf("Shutting down watcher for: %s", filename)
48 return
49 case event := <-watcher.Events:
50 // On Arch Linux, it appears Chmod events precede Remove events,
51 // which causes a race between action() and the coming Remove event.
52 // If the Remove wins, the action() (which calls
53 // UserMap.LoadAuthenticatedEmailsFile()) crashes when the file
54 // can't be opened.
55 if event.Op&(fsnotify.Remove|fsnotify.Rename|fsnotify.Chmod) != 0 {
56 logger.Printf("watching interrupted on event: %s", event)
57 watcher.Remove(filename)
58 WaitForReplacement(filename, event.Op, watcher)
59 }
60 logger.Printf("reloading after event: %s", event)
61 action()
62 case err = <-watcher.Errors:
63 logger.Printf("error watching %s: %s", filename, err)
64 }
65 }
66 }()
67 if err = watcher.Add(filename); err != nil {
68 logger.Fatal("failed to add ", filename, " to watcher: ", err)
69 }
70 logger.Printf("watching %s for updates", filename)