Enum rules

EnumRules describe the constraints applied to enum values.

const

const requires the field value to exactly match the specified enum value. If the field value doesn't match, an error message is generated.

enum.const example

enum MyEnum {
  MY_ENUM_UNSPECIFIED = 0;
  MY_ENUM_VALUE1 = 1;
  MY_ENUM_VALUE2 = 2;
}

message MyMessage {
  // The field `value` must be exactly MY_ENUM_VALUE1.
  MyEnum value = 1 [(buf.validate.field).enum.const = 1];
}

defined_only

defined_only requires the field value to be one of the defined values for this enum, failing on any undefined value.

enum.defined_only example

enum MyEnum {
  MY_ENUM_UNSPECIFIED = 0;
  MY_ENUM_VALUE1 = 1;
  MY_ENUM_VALUE2 = 2;
}

message MyMessage {
  // The field `value` must be a defined value of MyEnum.
  MyEnum value = 1 [(buf.validate.field).enum.defined_only = true];
}

in

in requires the field value to be equal to one of the specified enum values. If the field value doesn't match any of the specified values, an error message is generated.

enum.in example

enum MyEnum {
  MY_ENUM_UNSPECIFIED = 0;
  MY_ENUM_VALUE1 = 1;
  MY_ENUM_VALUE2 = 2;
}

message MyMessage {
  // The field `value` must be equal to one of the specified values.
  MyEnum value = 1 [(buf.validate.field).enum = { in: [1, 2]}];
}

not_in

not_in requires the field value to be not equal to any of the specified enum values. If the field value matches one of the specified values, an error message is generated.

enum.not_in example

enum MyEnum {
  MY_ENUM_UNSPECIFIED = 0;
  MY_ENUM_VALUE1 = 1;
  MY_ENUM_VALUE2 = 2;
}

message MyMessage {
  // The field `value` must not be equal to any of the specified values.
  MyEnum value = 1 [(buf.validate.field).enum = { not_in: [1, 2]}];
}

example

example specifies values that the field may have. These values SHOULD conform to other constraints. example values will not impact validation but may be used as helpful guidance on how to populate the given field.

enum.example example

enum MyEnum {
  MY_ENUM_UNSPECIFIED = 0;
  MY_ENUM_VALUE1 = 1;
  MY_ENUM_VALUE2 = 2;
}

message MyMessage {
    (buf.validate.field).enum.example = 1,
    (buf.validate.field).enum.example = 2
}