Schema

Every GraphQL API has a schema and that is used to define all the functionalities for an API. A schema is defined by passing 3 object types: Query, Mutation and Subscription.

Mutation and Subscription are optional, meanwhile Query has to always be there.

This is an example of a schema defined using Strawberry:

import strawberry

@strawberry.type
class Query:
    @strawberry.field
    def hello(self) -> str:
        return "Hello World"

schema = strawberry.Schema(Query)

API reference

class Schema(Query, mutation=None, subscription=None, **kwargs)

query: Type

The root query Strawberry type. Usually called Query.

mutation: Optional[Type] = None

The root mutation type. Usually called Mutation.

subscription: Optional[Type] = None

The root subscription type. Usually called Subscription.

config: Optional[StrawberryConfig] = None

Pass a StrawberryConfig object to configure how the schema is generated. Read more.

types: List[Type] = []

List of extra types to register with the Schema that are not directly linked to from the root Query.

from datetime import date
import strawberry

@strawberry.interface
class Customer:
    name: str

@strawberry.type
class Individual(Customer):
    date_of_birth: date

@strawberry.type
class Company(Customer):
    founded: date

@strawberry.type
class Query:
    @strawberry.field
    def get_customer(self, id: strawberry.ID) -> Customer  # note we're returning the interface here
        if id == "mark":
            return Individual(name="Mark", date_of_birth=date(1984, 5, 14))

        if id == "facebook":
            return Company(name="Facebook", founded=date(2004, 2, 1))

schema = strawberry.Schema(Query, types=[Individual, Company])

extensions: List[Type[Extension]] = []

List of extensions to add to your Schema.

scalar_overrides: Optional[Dict[object, ScalarWrapper]] = None

Override the implementation of the built in scalars. More information.

Methods

.execute() (async)

Executes a GraphQL operation against a schema (async)

async def execute(query, variable_values, context_value, root_value, operation_name)

query: str

The GraphQL document to be executed.

variable_values: Optional[Dict[str, Any]] = None

The variables for this operation.

context_value: Optional[Any] = None

The value of the context that will be passed down to resolvers.

root_value: Optional[Any] = None

The value for the root value that will passed to root resolvers.

operation_name: Optional[str] = None

The name of the operation you want to execute, useful when sending a document with multiple operations. If no operation_name is specified the first operation in the document will be executed.

.execute_sync()

Executes a GraphQL operation against a schema

def execute_sync(query, variable_values, context_value, root_value, operation_name)`

query: str

The GraphQL document to be executed.

variable_values: Optional[Dict[str, Any]] = None

The variables for this operation.

context_value: Optional[Any] = None

The value of the context that will be passed down to resolvers.

root_value: Optional[Any] = None

The value for the root value that will passed to root resolvers.

operation_name: Optional[str] = None

The name of the operation you want to execute, useful when sending a document with multiple operations. If no operation_name is specified the first operation in the document will be executed.

Handling execution errors

By default Strawberry will log any errors encountered during a query execution to a strawberry.execution logger. This behaviour can be changed by overriding the process_errors function on the strawberry.Schema class.

The default functionality looks like this:

# strawberry/schema/schema.py
from strawberry.types import ExecutionContext
 
logger = logging.getLogger("strawberry.execution")

class Schema:
    ...

    def process_errors(self, errors: List[GraphQLError], execution_context: ExecutionContext) -> None:
        for error in errors:
            # A GraphQLError wraps the underlying error so we have to access it
            # through the `original_error` property
            # https://graphql-core-3.readthedocs.io/en/latest/modules/error.html#graphql.error.GraphQLError
            actual_error = error.original_error or error
            logger.error(actual_error, exc_info=actual_error)