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: