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Improve config file watcher resilience #148

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Improve config file watcher resilience #148

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34 changes: 29 additions & 5 deletions cmd/idrac_exporter/config.go
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,8 @@ import (
"github.com/mrlhansen/idrac_exporter/internal/log"
)

// ...existing code...

func ReloadConfig(filename string) {
cfg := config.NewConfig()
old := config.Config
Expand Down Expand Up @@ -67,23 +69,43 @@ func WatchConfig(filename string) {
return
}

var retryCount int
var lastRetryTime time.Time
for {
select {
case event, ok := <-watcher.Events:
if !ok {
log.Error("Watcher events channel closed unexpectedly. Restarting watcher...")
go WatchConfig(filename)
return
}
if time.Since(lastReload) < time.Second {
break // needed to deduplicate e.g. multiple write events
break // deduplicate multiple write events
}
reload := false
if event.Has(fsnotify.Write) {
reload = true
} else if event.Has(fsnotify.Remove) {
} else if event.Has(fsnotify.Remove) || event.Has(fsnotify.Rename) {
watcher.Remove(event.Name)
err := watcher.Add(filename)
if err != nil {
return
now := time.Now()
if lastRetryTime.IsZero() || now.Sub(lastRetryTime) > 24*time.Hour {
retryCount = 0 // Expire retry count after 24 hours
}
lastRetryTime = now
for i := retryCount; i < 5; i++ {
err := watcher.Add(filename)
if err == nil {
retryCount = 0
break
}
log.Error("Failed to re-add watcher for %s (attempt %d): %v", filename, i+1, err)
time.Sleep(500 * time.Millisecond)
retryCount++
if retryCount == 5 {
log.Error("Watcher could not be re-added after multiple attempts. Restarting watcher...")
go WatchConfig(filename)
return
}
}
reload = true
}
Expand All @@ -93,6 +115,8 @@ func WatchConfig(filename string) {
}
case err, ok := <-watcher.Errors:
if !ok {
log.Error("Watcher errors channel closed unexpectedly. Restarting watcher...")
go WatchConfig(filename)
return
}
log.Error("File watcher error: %v", err)
Expand Down