pkg simpleschema: Add simple validation support

Author: DhairyaMajmudar

pkg/simpleschema/markers.go

@@ -50,14 +50,16 @@ const (
 	MarkerTypeMinimum MarkerType = "minimum"
 	// MarkerTypeMaximum represents the `maximum` marker.
 	MarkerTypeMaximum MarkerType = "maximum"
+	// MarkerTypeValidation represents the `validation` marker.
+	MarkerTypeValidation MarkerType = "validation"
 	// MarkerTypeEnum represents the `enum` marker.
 	MarkerTypeEnum MarkerType = "enum"
 )
 
 func markerTypeFromString(s string) (MarkerType, error) {
 	switch MarkerType(s) {
 	case MarkerTypeRequired, MarkerTypeDefault, MarkerTypeDescription,
-		MarkerTypeMinimum, MarkerTypeMaximum, MarkerTypeEnum:
+		MarkerTypeMinimum, MarkerTypeMaximum, MarkerTypeValidation, MarkerTypeEnum:
 		return MarkerType(s), nil
 	default:
 		return "", fmt.Errorf("unknown marker type: %s", s)

pkg/simpleschema/transform.go

@@ -219,6 +219,17 @@ func (tf *transformer) applyMarkers(schema *extv1.JSONSchemaProps, markers []*Ma
 				return fmt.Errorf("failed to parse maximum enum value: %w", err)
 			}
 			schema.Maximum = &val
+		case MarkerTypeValidation:
+			if marker.Value == "" {
+				return fmt.Errorf("validation failed")
+			}
+			validation := []extv1.ValidationRule{
+				{
+					Rule:    marker.Value,
+					Message: "validation failed",
+				},
+			}
+			schema.XValidations = validation
 		case MarkerTypeEnum:
 			var enumJSONValues []extv1.JSON
 

pkg/simpleschema/transform_test.go

@@ -360,6 +360,66 @@ func TestBuildOpenAPISchema(t *testing.T) {
 			want:    nil,
 			wantErr: true,
 		},
+		{
+			name: "Simple string validation",
+			obj: map[string]interface{}{
+				"name": `string | validation="self.name != 'invalid'"`,
+			},
+			want: &extv1.JSONSchemaProps{
+				Type: "object",
+				Properties: map[string]extv1.JSONSchemaProps{
+					"name": {
+						Type: "string",
+						XValidations: []extv1.ValidationRule{
+							{
+								Rule:    "self.name != 'invalid'",
+								Message: "validation failed",
+							},
+						},
+					},
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "Multiple field validations",
+			obj: map[string]interface{}{
+				"age":  `integer | validation="self.age >= 0 && self.age <= 120"`,
+				"name": `string | validation="self.name.length() >= 3"`,
+			},
+			want: &extv1.JSONSchemaProps{
+				Type: "object",
+				Properties: map[string]extv1.JSONSchemaProps{
+					"age": {
+						Type: "integer",
+						XValidations: []extv1.ValidationRule{
+							{
+								Rule:    "self.age >= 0 && self.age <= 120",
+								Message: "validation failed",
+							},
+						},
+					},
+					"name": {
+						Type: "string",
+						XValidations: []extv1.ValidationRule{
+							{
+								Rule:    "self.name.length() >= 3",
+								Message: "validation failed",
+							},
+						},
+					},
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "Empty validation",
+			obj: map[string]interface{}{
+				"age": `integer | validation=""`,
+			},
+			want:    nil,
+			wantErr: true,
+		},
 	}
 
 	for _, tt := range tests {