address pr comments

libbeat/processors/cache/config.go

@@ -103,7 +103,7 @@ type memConfig struct {
 
 type fileConfig struct {
 	ID            string        `config:"id"`
-	WriteOutEvery time.Duration `config:"write_frequency"`
+	WriteOutEvery time.Duration `config:"write_interval"`
 }
 
 func (cfg *storeConfig) Validate() error {

libbeat/processors/cache/config_test.go

@@ -48,7 +48,7 @@ put:
 backend:
   file:
     id: aidmaster
-    write_frequency: 15m
+    write_interval: 15m
 put:
   ttl: 168h
   key_field: crowdstrike.aid

libbeat/processors/cache/file_store.go

@@ -169,7 +169,12 @@ func (c *fileStore) readState() {
 		err = dec.Decode(&e)
 		if err != nil {
 			if err != io.EOF {
-				c.log.Errorw("failed to read state element", "error", err)
+				switch err := err.(type) {
+				case *json.SyntaxError:
+					c.log.Errorw("failed to read state element", "error", err, "path", c.path, "offset", err.Offset)
+				default:
+					c.log.Errorw("failed to read state element", "error", err, "path", c.path)
+				}
 			}
 			break
 		}
@@ -219,19 +224,24 @@ func (c *fileStore) writeState(final bool) {
 		}
 		return
 	}
-	f, err := os.CreateTemp("", "")
+	f, err := os.CreateTemp(filepath.Dir(c.path), "")
 	if err != nil {
 		c.log.Errorw("failed to open file to write state", "error", err)
 		return
 	}
-	// We are writing into tmp, so make sure we are private.
+	// Try to make sure we are private.
 	err = os.Chmod(f.Name(), 0o600)
 	if err != nil {
 		c.log.Errorw("failed to set state file mode", "error", err)
 		return
 	}
 	tmp := f.Name()
 	defer func() {
+		err = f.Sync()
+		if err != nil {
+			c.log.Errorw("failed to sync file after writing state", "error", err)
+			return
+		}
 		err = f.Close()
 		if err != nil {
 			c.log.Errorw("failed to close file after writing state", "error", err)