Schema Directives

Strawberry supports schema directives, which are directives that don't change the behavior of your GraphQL schema but instead provide a way to add additional metadata to it.

For example our Apollo Federation integration is based on schema directives.

Let's see how you can implement a schema directive in Strawberry, here we are creating a directive called keys that can be applied to Object types definitions and accepts one parameter called fields. Note that directive names, by default, are converted to camelCase on the GraphQL schema.

Here's how we can use it in our schema:

import strawberry
from strawberry.schema_directive import Location


@strawberry.schema_directive(locations=[Location.OBJECT])
class Keys:
    fields: str


from .directives import Keys


@strawberry.type(directives=[Keys(fields="id")])
class User:
    id: strawberry.ID
    name: str

This will result in the following schema:

type User @keys(fields: "id") {
  id: ID!
  name: String!
}

Overriding field names

You can use strawberry.directive_field to override the name of a field:

@strawberry.schema_directive(locations=[Location.OBJECT])
class Keys:
    fields: str = strawberry.directive_field(name="as")

Locations

Schema directives can be applied to many different parts of a schema. Here's the list of all the allowed locations: