Flask

Dependency injection for Flask is available in the wireup.integration.flask module.

Features:

• Dependency injection in function-based and class-based views (sync and async)
• Request-scoped container lifecycle management.

---

Initialize the integration

To initialize the integration, call wireup.integration.flask.setup after adding all views and configuration.

from wireup import Inject, Injected, service

app = Flask(__name__)
app.config["FOO"] = "bar"

container = wireup.create_sync_container(
    # service_modules is a list of top-level modules with service registrations.
    service_modules=[services],
    parameters={
        **app.config, # Optionally expose flask configuration to the container.
        "FOO": "bar"
    }
)

# Initialize the integration.
# Must be called after views and configuration have been added.
wireup.integration.flask.setup(container, app)

Inject in Flask Views

To inject dependencies, add the type to the views' signature and annotate them as necessary. See Annotations for more details.

Flask View

@app.get("/random")
def get_random(random: Injected[RandomService]):
    return {"lucky_number": random.get_random()}

@app.get("/env")
def get_environment(
    is_debug: Annotated[bool, Inject(param="DEBUG")], 
    foo: Annotated[str, Inject(param="FOO")]
):
    return {"debug": is_debug, "foo": foo}

Accessing the Container

If you ever need to access the Wireup container directly, use the provided functions:

from wireup.integration.flask import get_app_container, get_request_container

# Get application-wide container
app_container = get_app_container(app)

# Get request-scoped container
request_container = get_request_container()

Testing

For general testing tips with Wireup refer to the test docs. With the Flask integration, you can override dependencies in the container as follows.

test_thing.py

from wireup.integration.flask import get_app_container

def test_override():
    class DummyGreeter(GreeterService):
        def greet(self, name: str) -> str:
            return f"Hi, {name}"

    with get_app_container(app).override.service(GreeterService, new=DummyGreeter()):
        res = self.client.get("/greet?name=Test")

See Flask integration tests for more examples.

API Reference

• flask_integration