fix(pkg/storage): write creation date in storage pkg

pkg/storage/storage.go

@@ -106,24 +106,28 @@ func Round(measuredValues []*types.MeasuredValue, round float64) {
 // data. The scheme must be matched to a storage provider, if the scheme is not
 // implemented, the function returns an error
 func Write(ctx context.Context, measuredValues []*types.MeasuredValue, storageEndpoint *url.URL) error {
+	writeCreationDate(measuredValues)
 	switch storageEndpoint.Scheme {
 	case "file":
 		measuredValueLogfile := logfile.New(storageEndpoint.Path)
-		storedMeasuredValues, err := measuredValueLogfile.Read()
-		if err != nil {
-			return err
-		}
-		storedMeasuredValues = append(storedMeasuredValues, measuredValues...)
-		return measuredValueLogfile.Write(storedMeasuredValues)
+		return measuredValueLogfile.Write(measuredValues)
 	case "postgres":
 		database, err := db.New(storageEndpoint)
 		if err != nil {
 			return err
 		}
 		defer database.Close()
-		if err := database.InsertMeasuredValues(ctx, measuredValues); err != nil {
-			return err
+		return database.InsertMeasuredValues(ctx, measuredValues)
+	default:
+		return fmt.Errorf("No supported scheme")
+	}
+}
+
+func writeCreationDate(measuredValues []*types.MeasuredValue) {
+	now := format.FormatedTime()
+	for _, measuredValue := range measuredValues {
+		if measuredValue.CreationDate == nil {
+			measuredValue.CreationDate = &now
 		}
 	}
-	return fmt.Errorf("No supported scheme")
 }