Flask Integration

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

• Automatic Dependency Management

  ---

  Inject dependencies in routes and automatically manage container lifecycle.

• Shared business logic

  ---

  Wireup is framework-agnostic. Share the service layer between web applications and other interfaces, such as a CLI.

Initialize the integration

First, create a sync container with your service modules:

from flask import Flask
from wireup import Inject, Injected, service

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

container = wireup.create_sync_container(
    service_modules=[services],
    parameters={
        **app.config,  # Optionally expose flask configuration to the container
        "API_KEY": "secret"
    }
)

Then initialize the integration by calling wireup.integration.flask.setup after adding all views and configuration:

# 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

To access the Wireup container directly, use the following 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