7. Architecture

Axes is based on the existing Django authentication backend architecture and framework for recognizing users and aims to be compatible with the stock design and implementation of Django while offering extensibility and configurability for using the Axes authentication monitoring and logging for users of the package as well as 3rd party package vendors such as Django REST Framework, Django Allauth, Python Social Auth and so forth.

The development of custom 3rd party package support are active goals, but you should check the up-to-date documentation and implementation of Axes for current compatibility before using Axes with custom solutions and make sure that authentication monitoring is working correctly.

This document describes the Django authentication flow and how Axes augments it to achieve authentication and login monitoring and lock users out on too many access attempts.

Django Axes authentication flow

Axes offers a few additions to the Django authentication flow that implement the login monitoring and lockouts through a swappable handler API and configuration flags that users and package vendors can use to customize Axes or their own projects as they best see fit.

The following diagram visualizes the Django login flow and highlights the following extra steps that Axes adds to it with the 1. Authentication backend, 2. Signal receivers, and 3. Middleware.

Django Axes augmented authentication flow with custom authentication backend, signal receivers, and middleware

When a user tries to log in in Django, the login is usually performed by running a number of authentication backends that check user login information by calling the authenticate function, which either returns a Django compatible User object or a None.

If an authentication backend does not approve a user login, it can raise a PermissionDenied exception, which immediately skips the rest of the authentication backends, triggers the user_login_failed signal, and then returns a None to the calling function, indicating that the login failed.

Axes implements authentication blocking with the custom AxesBackend authentication backend which checks every request coming through the Django authentication flow and verifies they are not blocked, and allows the requests to go through if the check passes.

If the authentication attempt matches a lockout rule, e.g. it is from a blacklisted IP or exceeds the maximum configured authentication attempts, it is blocked by raising the PermissionDenied exception in the backend.

Axes monitors logins with the user_login_failed signal receiver and records authentication failures from both the AxesBackend and other authentication backends and tracks the failed attempts by tracking the attempt IP address, username, user agent, or all of them.

If the lockout rules match, then Axes marks the request as locked by setting a special attribute into the request. The AxesMiddleware then processes the request, returning a lockout response to the user, if the flag has been set.

Axes assumes that the login views either call the authenticate method to log in users or otherwise take care of notifying Axes of authentication attempts and failures the same way Django does via authentication signals.

The login flows can be customized and the Axes authentication backend, middleware, and signal receivers can easily be swapped to alternative implementations.