Enums

A Enum is a special GraphQL type that represents a set of symbolic names (members) bound to unique, constant values.

Definition

You can create an Enum using classes:

import graphene

class Episode(graphene.Enum):
    NEWHOPE = 4
    EMPIRE = 5
    JEDI = 6

But also using instances of Enum:

Episode = graphene.Enum('Episode', [('NEWHOPE', 4), ('EMPIRE', 5), ('JEDI', 6)])

Value descriptions

It’s possible to add a description to an enum value, for that the enum value needs to have the description property on it.

class Episode(graphene.Enum):
    NEWHOPE = 4
    EMPIRE = 5
    JEDI = 6

    @property
    def description(self):
        if self == Episode.NEWHOPE:
            return 'New Hope Episode'
        return 'Other episode'

Usage with Python Enums

In case the Enums are already defined it’s possible to reuse them using the Enum.from_enum function.

graphene.Enum.from_enum(AlreadyExistingPyEnum)

Enum.from_enum supports a description and deprecation_reason lambdas as input so you can add description etc. to your enum without changing the original:

graphene.Enum.from_enum(AlreadyExistingPyEnum, description=lambda value: return 'foo' if value == AlreadyExistingPyEnum.Foo else 'bar')

Notes

graphene.Enum uses enum.Enum internally (or a backport if that’s not available) and can be used in a similar way, with the exception of member getters.

In the Python Enum implementation you can access a member by initing the Enum.

from enum import Enum
class Color(Enum):
    RED = 1
    GREEN = 2
    BLUE = 3

assert Color(1) == Color.RED

However, in Graphene Enum you need to call get to have the same effect:

from graphene import Enum
class Color(Enum):
    RED = 1
    GREEN = 2
    BLUE = 3

assert Color.get(1) == Color.RED