Partially handle case of not found tokens

cmd/revad/pkg/config/templates.go

@@ -132,7 +132,8 @@ func applyTemplateString(l Lookuper, p setter, v reflect.Value) error {
 			return err
 		}
 		if val == nil {
-			val = ""
+			// key was not found, just keep it but stop further parsing
+			break
 		}
 
 		new, err := replaceTemplate(s, tmpl, val)
@@ -175,7 +176,8 @@ func applyTemplateInterface(l Lookuper, p setter, v reflect.Value) error {
 			return err
 		}
 		if val == nil {
-			val = ""
+			// key was not found, just keep it but stop further parsing
+			break
 		}
 
 		new, err := replaceTemplate(s, tmpl, val)
@@ -214,7 +216,10 @@ func replaceTemplate(original, tmpl string, val any) (any, error) {
 	if !ok {
 		return nil, fmt.Errorf("value %v cannot be converted as string in the template %s", val, original)
 	}
-	return strings.Replace(original, tmpl, s, 1), nil
+	if s != "" {
+		return strings.Replace(original, tmpl, s, 1), nil
+	}
+	return original, nil
 }
 
 func convertToString(val any) (string, bool) {

cmd/revad/pkg/config/templates_test.go

@@ -96,10 +96,11 @@ func TestApplyTemplate(t *testing.T) {
 						Config: map[string]any{
 							"drivers": map[string]any{
 								"sql": map[string]any{
-									"db_username": "{{ vars.db_username }}",
-									"db_password": "{{ vars.db_password }}",
-									"key":         "value",
-									"port":        "{{ vars.port }}",
+									"db_username":    "{{ vars.db_username }}",
+									"db_password":    "{{ vars.db_password }}",
+									"key":            "value",
+									"port":           "{{ vars.port }}",
+                                                                        "user_and_token": "{{ vars.db_username }} and {{.Token}}",
 								},
 							},
 						},
@@ -125,10 +126,11 @@ func TestApplyTemplate(t *testing.T) {
 	assert.ErrorIs(t, err, nil)
 	assert.Equal(t, "localhost:1901", cfg2.Shared.GatewaySVC)
 	assert.Equal(t, map[string]any{
-		"db_username": "root",
-		"db_password": "secretpassword",
-		"key":         "value",
-		"port":        1000,
+		"db_username":    "root",
+		"db_password":    "secretpassword",
+		"key":            "value",
+		"port":           1000,
+                "user_and_token": "root and {{.Token}}",
 	}, cfg2.GRPC.Services["authregistry"][0].Config["drivers"].(map[string]any)["sql"])
 	assert.Equal(t, map[string]any{
 		"db_host": "http://localhost:1000",