dir2config: templates: 'default' fn

cmd/dkl-dir2config/render-context.go

@@ -234,6 +234,24 @@ func (ctx *renderContext) templateFuncs(ctxMap map[string]interface{}) map[strin
 
 	funcs := clusterFuncs(ctx.Cluster)
 	for k, v := range map[string]interface{}{
+		"default": func(value, defaultValue any) any {
+			switch v := value.(type) {
+			case string:
+				if v != "" {
+					return v
+				}
+			case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, float32, float64:
+				if v != 0 {
+					return v
+				}
+
+			default:
+				if v != nil {
+					return v
+				}
+			}
+			return defaultValue
+		},
 		"tls_key": func(name string) (string, error) {
 			return getKeyCert(name, "tls_key")
 		},