oauth2-proxy/watcher.go
Mitsuo Heijo dd05e7ff0b
Add new linters (#486)
* add new linters and fix issues

* fix deprecated warnings

* simplify return

* update CHANGELOG

* fix staticcheck issues

* remove a deprecated linter, minor fixes of variable initialization
2020-04-14 09:36:44 +01:00

73 lines
2.0 KiB
Go

// +build go1.3,!plan9,!solaris
package main
import (
"os"
"path/filepath"
"time"
"github.com/fsnotify/fsnotify"
"github.com/oauth2-proxy/oauth2-proxy/pkg/logger"
)
// WaitForReplacement waits for a file to exist on disk and then starts a watch
// for the file
func WaitForReplacement(filename string, op fsnotify.Op,
watcher *fsnotify.Watcher) {
const sleepInterval = 50 * time.Millisecond
// Avoid a race when fsnofity.Remove is preceded by fsnotify.Chmod.
if op&fsnotify.Chmod != 0 {
time.Sleep(sleepInterval)
}
for {
if _, err := os.Stat(filename); err == nil {
if err := watcher.Add(filename); err == nil {
logger.Printf("watching resumed for %s", filename)
return
}
}
time.Sleep(sleepInterval)
}
}
// WatchForUpdates performs an action every time a file on disk is updated
func WatchForUpdates(filename string, done <-chan bool, action func()) {
filename = filepath.Clean(filename)
watcher, err := fsnotify.NewWatcher()
if err != nil {
logger.Fatal("failed to create watcher for ", filename, ": ", err)
}
go func() {
defer watcher.Close()
for {
select {
case <-done:
logger.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 {
logger.Printf("watching interrupted on event: %s", event)
watcher.Remove(filename)
WaitForReplacement(filename, event.Op, watcher)
}
logger.Printf("reloading after event: %s", event)
action()
case err = <-watcher.Errors:
logger.Printf("error watching %s: %s", filename, err)
}
}
}()
if err = watcher.Add(filename); err != nil {
logger.Fatal("failed to add ", filename, " to watcher: ", err)
}
logger.Printf("watching %s for updates", filename)
}