generate falgs based on struct options instead of defining them externally

utils/default.go

@@ -0,0 +1,41 @@
+package utils
+
+import (
+	"fmt"
+	"github.com/fatih/structs"
+	"reflect"
+	"strconv"
+)
+
+func ApplyDefaultValues(struct_ interface{}) (err error) {
+	o := structs.New(struct_)
+
+	for _, field := range o.Fields() {
+		defaultValue := field.Tag("default")
+		if defaultValue == "" {
+			continue
+		}
+		var val interface{}
+		switch field.Kind() {
+		case reflect.String:
+			val = defaultValue
+		case reflect.Bool:
+			if defaultValue == "true" {
+				val = true
+			} else if defaultValue == "false" {
+				val = false
+			} else {
+				return fmt.Errorf("invalid bool expression: %v, use true/false", defaultValue)
+			}
+		case reflect.Int:
+			val, err = strconv.Atoi(defaultValue)
+			if err != nil {
+				return err
+			}
+		default:
+			val = field.Value()
+		}
+		field.Set(val)
+	}
+	return nil
+}