Add min/max properties validation

pkg/crd/markers/validation.go

@@ -40,6 +40,8 @@ var ValidationMarkers = mustMakeAllWithPrefix("kubebuilder:validation", markers.
 	ExclusiveMaximum(false),
 	ExclusiveMinimum(false),
 	MultipleOf(0),
+	MinProperties(0),
+	MaxProperties(0),
 
 	// string markers
 
@@ -145,6 +147,14 @@ type MinItems int
 // UniqueItems specifies that all items in this list must be unique.
 type UniqueItems bool
 
+// +controllertools:marker:generateHelp:category="CRD validation"
+// MaxProperties restricts the number of keys in an object
+type MaxProperties int
+
+// +controllertools:marker:generateHelp:category="CRD validation"
+// MinProperties restricts the number of keys in an object
+type MinProperties int
+
 // +controllertools:marker:generateHelp:category="CRD validation"
 // Enum specifies that this (scalar) field is restricted to the *exact* values specified here.
 type Enum []interface{}
@@ -289,6 +299,24 @@ func (m UniqueItems) ApplyToSchema(schema *apiext.JSONSchemaProps) error {
 	return nil
 }
 
+func (m MinProperties) ApplyToSchema(schema *apiext.JSONSchemaProps) error {
+	if schema.Type != "object" {
+		return fmt.Errorf("must apply minproperties to an object")
+	}
+	val := int64(m)
+	schema.MinProperties = &val
+	return nil
+}
+
+func (m MaxProperties) ApplyToSchema(schema *apiext.JSONSchemaProps) error {
+	if schema.Type != "object" {
+		return fmt.Errorf("must apply maxproperties to an object")
+	}
+	val := int64(m)
+	schema.MaxProperties = &val
+	return nil
+}
+
 func (m Enum) ApplyToSchema(schema *apiext.JSONSchemaProps) error {
 	// TODO(directxman12): this is a bit hacky -- we should
 	// probably support AnyType better + using the schema structure