Update to shutdown worker for WAL checkpointing mode

configs/config-demo.json

@@ -21,6 +21,7 @@
   ],
   "metric-store": {
     "checkpoints": {
+      "file-format": "wal",
       "interval": "12h"
     },
     "retention-in-memory": "48h",

pkg/metricstore/metricstore.go

@@ -294,7 +294,7 @@ func Shutdown() {
 		var hostDirs []string
 		files, hostDirs, err = ms.ToCheckpointWAL(Keys.Checkpoints.RootDir, from.Unix(), time.Now().Unix())
 		if err == nil {
-			RotateWALFiles(hostDirs)
+			RotateWALFilesAfterShutdown(hostDirs)
 		}
 	} else {
 		files, err = ms.ToCheckpoint(Keys.Checkpoints.RootDir, from.Unix(), time.Now().Unix())

pkg/metricstore/walCheckpoint.go

@@ -116,7 +116,6 @@ type walFileState struct {
 // Also handles WAL rotation requests from the checkpoint goroutine.
 func WALStaging(wg *sync.WaitGroup, ctx context.Context) {
 	wg.Go(func() {
-
 		if Keys.Checkpoints.FileFormat == "json" {
 			return
 		}
@@ -235,6 +234,17 @@ func RotateWALFiles(hostDirs []string) {
 	}
 }
 
+// RotateWALFiles sends rotation requests for the given host directories
+// and blocks until all rotations complete.
+func RotateWALFilesAfterShutdown(hostDirs []string) {
+	for _, dir := range hostDirs {
+		walPath := path.Join(dir, "current.wal")
+		if err := os.Remove(walPath); err != nil && !os.IsNotExist(err) {
+			cclog.Errorf("[METRICSTORE]> WAL: remove %s: %v", walPath, err)
+		}
+	}
+}
+
 // buildWALPayload encodes a WALMessage into a binary payload (without magic/length/CRC).
 func buildWALPayload(msg *WALMessage) []byte {
 	size := 8 + 2 + len(msg.MetricName) + 1 + 4