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

strawberry.Schema(
    query: Type,
    mutation: Type = None,
    subscription: Type = None
    validate_queries: bool = True
)

Creates a GraphQL schema

• query: The root query type
• mutation: The root mutation type
• subscription: The root subscription type

.execute() (async)

Executes a GraphQL operation against a schema (async)

execute(query, variable_values, context_value, root_value, operation_name, validate_queries)

.execute_sync()

Executes a GraphQL operation against a schema

execute_sync(query, variable_values, context_value, root_value, operation_name, validate_queries)

Query validation

When creating a schema you can decide to disable the validation of the queries sent from clients. This can be useful to improve performances in some specific cases, for example when dealing with internal APIs where queries can be trusted.

⚠️ NOTE: make sure you understand the trade-offs of disabling validation, for example when asking for field that don't exist the GraphQL schema won't return any error, which is something that breaks the safety of having a typed schema.

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)