FastAPI-Azure-Auth

Azure Entra ID Authentication for FastAPI apps made easy.

🚀 Description

FastAPI is a modern, fast (high-performance), web framework for building APIs with Python, based on standard Python type hints.

At Intility we use FastAPI for both internal (single-tenant) and customer-facing (multi-tenant) APIs. This package enables our developers (and you 😊) to create features without worrying about authentication and authorization.

Also, we're hiring!

📚 Resources

The documentation contains a full tutorial on how to configure Azure Entra ID and FastAPI for single- and multi-tenant applications as well as B2C apps. It includes examples on how to lock down your APIs to certain scopes, tenants, roles etc. For first time users it's strongly advised to set up your application exactly how it's described there, and then alter it to your needs later.

MIT License | Documentation | GitHub

⚡ Setup

This is a tl;dr intended to give you an idea of what this package does and how to use it. For a more in-depth tutorial and settings reference you should read the documentation.

1. Install this library:

pip install fastapi-azure-auth
# or
poetry add fastapi-azure-auth

2. Configure your FastAPI app

Include swagger_ui_oauth2_redirect_url and swagger_ui_init_oauth in your FastAPI app initialization:

# file: main.py
app = FastAPI(
    ...
    swagger_ui_oauth2_redirect_url='/oauth2-redirect',
    swagger_ui_init_oauth={
        'usePkceWithAuthorizationCodeGrant': True,
        'clientId': settings.OPENAPI_CLIENT_ID,
    },
)

3. Setup CORS

Ensure you have CORS enabled for your local environment, such as http://localhost:8000.

4. Configure FastAPI-Azure-Auth

Configure either SingleTenantAzureAuthorizationCodeBearer, MultiTenantAzureAuthorizationCodeBearer or B2CMultiTenantAuthorizationCodeBearer

# file: demoproj/api/dependencies.py
from fastapi_azure_auth.auth import SingleTenantAzureAuthorizationCodeBearer

azure_scheme = SingleTenantAzureAuthorizationCodeBearer(
    app_client_id=settings.APP_CLIENT_ID,
    tenant_id=settings.TENANT_ID,
    scopes={
        f'api://{settings.APP_CLIENT_ID}/user_impersonation': 'user_impersonation',
    }
)

or for multi-tenant applications:

# file: demoproj/api/dependencies.py
from fastapi_azure_auth.auth import MultiTenantAzureAuthorizationCodeBearer

azure_scheme = MultiTenantAzureAuthorizationCodeBearer(
    app_client_id=settings.APP_CLIENT_ID,
    scopes={
        f'api://{settings.APP_CLIENT_ID}/user_impersonation': 'user_impersonation',
    },
    validate_iss=False
)

To validate the iss, configure an iss_callable.

5. Configure dependencies

Add azure_scheme as a dependency for your views/routers, using either Security() or Depends().

# file: main.py
from demoproj.api.dependencies import azure_scheme

app.include_router(api_router, prefix=settings.API_V1_STR, dependencies=[Security(azure_scheme, scopes=['user_impersonation'])])

6. Load config on startup

Optional but recommended.

# file: main.py
@app.on_event('startup')
async def load_config() -> None:
    """
    Load OpenID config on startup.
    """
    await azure_scheme.openid_config.load_config()

📄 Example OpenAPI documentation

Your OpenAPI documentation will get an Authorize button, which can be used to authenticate.

The user can select which scopes to authenticate with, based on your configuration.