Benson Wong
66639e83f7
The fsnotify-based config watcher does not work reliably when the config file is bind-mounted into a Docker container as an individual file, and mishandles k8s ConfigMap projections (atomically swapped symlinks). Replace it with a small os.Stat-polling watcher and add SIGHUP as an explicit reload signal. - new proxy/configwatcher package: 2s os.Stat poller, follows symlinks, fires on mtime/size change and on missing -> present transitions - SIGHUP triggers reload unconditionally (works without --watch-config) via the same ConfigFileChangedEvent pipeline so the UI sees identical state transitions - watcher goroutine now exits cleanly on shutdown via a context - drop github.com/fsnotify/fsnotify dependency fixes #682
86 lines
1.9 KiB
Go
86 lines
1.9 KiB
Go
// Package configwatcher provides a simple cross-platform file watcher based
|
|
// on os.Stat polling. It works correctly inside Docker containers where the
|
|
// config file is bind-mounted as an individual file, and for k8s ConfigMap
|
|
// projections (which present the file as a symlink to an atomically swapped
|
|
// target) — both cases where inotify-based watchers are unreliable.
|
|
package configwatcher
|
|
|
|
import (
|
|
"context"
|
|
"errors"
|
|
"io/fs"
|
|
"log"
|
|
"os"
|
|
"time"
|
|
)
|
|
|
|
const DefaultInterval = 2 * time.Second
|
|
|
|
type Watcher struct {
|
|
Path string
|
|
Interval time.Duration
|
|
OnChange func()
|
|
}
|
|
|
|
type snapshot struct {
|
|
exists bool
|
|
modTime time.Time
|
|
size int64
|
|
}
|
|
|
|
// Run blocks until ctx is canceled. It polls Path on Interval and invokes
|
|
// OnChange whenever the file's modification time or size changes, or when
|
|
// the file reappears after being missing. The baseline poll establishes
|
|
// initial state and does not fire OnChange.
|
|
func (w *Watcher) Run(ctx context.Context) {
|
|
interval := w.Interval
|
|
if interval <= 0 {
|
|
interval = DefaultInterval
|
|
}
|
|
|
|
prev := stat(w.Path)
|
|
|
|
ticker := time.NewTicker(interval)
|
|
defer ticker.Stop()
|
|
|
|
for {
|
|
select {
|
|
case <-ctx.Done():
|
|
return
|
|
case <-ticker.C:
|
|
cur := stat(w.Path)
|
|
if changed(prev, cur) && w.OnChange != nil {
|
|
w.OnChange()
|
|
}
|
|
prev = cur
|
|
}
|
|
}
|
|
}
|
|
|
|
func stat(path string) snapshot {
|
|
fi, err := os.Stat(path)
|
|
if err != nil {
|
|
if !errors.Is(err, fs.ErrNotExist) {
|
|
log.Printf("configwatcher: stat %s: %v", path, err)
|
|
}
|
|
return snapshot{}
|
|
}
|
|
return snapshot{
|
|
exists: true,
|
|
modTime: fi.ModTime(),
|
|
size: fi.Size(),
|
|
}
|
|
}
|
|
|
|
func changed(prev, cur snapshot) bool {
|
|
// Present → missing: stay quiet (likely a transient rename-style write).
|
|
// Missing → present: fire so we reload as soon as the file comes back.
|
|
if !cur.exists {
|
|
return false
|
|
}
|
|
if !prev.exists {
|
|
return true
|
|
}
|
|
return !prev.modTime.Equal(cur.modTime) || prev.size != cur.size
|
|
}
|