politico-staff-auth 0.0.6

Staff authentication via Slack, the POLITICO way.

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POLITICO staff auth

This app stores a handful of useful utilities we use across our various Django apps at POLITICO to integrate our staff authorization and authentication, which is implemented with Slack via Python Social Auth.

Requirements

• Python 3.6 — brew install python

• Pipenv — brew install pipenv

• Django (tested on versions 2.1.x and 2.2.x)

• A Slack workspace with users

• A Slack app connected to that workspace, with a "Redirect URL" entry matching the following pattern:

  http://<your server name>/social/complete/slack/

  (Note: you can have multiple "Redirect URLs" for the same app. For local development, you'll be aliasing localhost to a subdomain of your choosing, as described in the "Domain resolution" section below.)

• Optional: PostgreSQL — brew install postgresql

What's inside

./staff_auth/

The app that handles staff Slack authorization and authentication.

./staff_auth/templates/admin/login.html and ./staff_auth/static/staff_auth/css/custom-login.css

Custom HTML and CSS to add a "Staff login (with Slack)" button to the standard Django admin login form.

staff_auth.backend.WorkspaceSpecificSlackOAuth2

A subclass of Python Social Auth's Slack authentication backend. Unlike the original, this variant forces users to log in with credentials from the specified Slack workspace (rather than from any Slack workspace).

staff_auth.middleware.InvalidWorkspaceErrorMiddleware

A middleware that listens for Python Social Auth's AuthForbidden exceptions and maps them to rich output in a StaffAuthErrorView page.

staff_auth.pipeline.associate_by_email

A function that finds any existing Django users with the same email address as the sign-er in-er, and ties this new sign-in to the same account — but only if that user has previously had a separate social-auth tie in.

staff_auth.pipeline.promote_staffer_to_staff

A function that promotes all Slack-authenticated users to "staff" status (meaning they can log into the Django admin) when they first sign in with their Slack credentials.

staff_auth.pipeline.promote_manager_to_superuser

A function that promotes all Slack-authenticated users to "superuser" status (meaning they can log into the Django admin) when they first sign in with their Slack credentials — if the email address on their Slack account matches an email address found in the settings.MANAGERS list.

staff_auth.views.StaffAuthErrorView

An error page shown to users if they try and log in via a different Slack workspace.

(Note that the HTML and CSS for this view live at ./staff_auth/templates/staff_auth/auth-error.html and ./staff_auth/static/staff_auth/css/page-styles.css, respectively.)

./example/

An example Django project that shows how we implement staff Slack access.

Inside this directory you'll find a standard (if threadbare) Django app, with an example .env file, a Pipfile and a manage.py script at the top level.

Inside the exampleapp subdirectory is this example app's settings.py file (where you can see an example implementation of politico-staff-auth's required configuration variables), along with a urls.py file to demonstrate how that piece of wiring should be performed. Standard helper files including wsgi.py can also be found in this subdirectory.

Launching the example app

1. Change into the ./example/ directory one level below this README and install dependencies.

   cd ./example/
   pipenv install
   

2. Create a .env file from the .env.example template, and insert appropriate values.

   cp .env.example .env
   

   See the "Configuration" section below for more information about what goes in each setting.

3. Create a new blank database, then populate it with the necessary tables.

   make database
   pipenv run python manage.py migrate
   

4. Start the Django test server.

   pipenv run python manage.py runserver
   

5. Navigate to the admin site on your test server and click the "Staff login" button.

Installation

1. Install from PyPI:

   pipenv install politico-staff-auth
   

2. Add staff_auth and social_django to the list of apps installed into Django.

   In your project's settings.py:

   INSTALLED_APPS = [
     "staff_auth",
   
     # ...
     # Existing installed apps
     # ...
   
     "social_django",
   ]
   

   NOTE: The staff_auth app must be first in this list (or, at least, must appear before the pre-existing line django.contrib.admin). The social_django line should appear after all apps that are distributed with Django itself.

3. Add the credentials for your staff's Slack workspace.

   In your project's settings.py:

   STAFF_AUTH_SLACK_KEY = "auth-key"
   
   STAFF_AUTH_SLACK_SECRET = "secret-key"
   
   STAFF_AUTH_SLACK_TEAM = "my-value-here"
   

   For more on these values, see the "Configuration" section below.

   NOTE: We recommend reading these values from environment variables, but there's no accounting for taste.

4. Add the required middleware for rich login error messages.

   In your project's settings.py:

   MIDDLEWARE = [
       # ...
       # Existing middleware
       # ...
   
       "staff_auth.middleware.InvalidWorkspaceErrorMiddleware",
   ]
   

   NOTE: The staff_auth.middleware.InvalidWorkspaceErrorMiddleware entry should go at the end of the existing MIDDLEWARE list.

5. With the previous steps complete, you can now implement the basic staff auth settings.

   In your project's settings.py:

   from staff_auth.configured_settings import configure_staff_auth
   
   staff_auth_settings = configure_staff_auth(
       key=STAFF_AUTH_SLACK_KEY,
       secret=STAFF_AUTH_SLACK_SECRET,
       team=STAFF_AUTH_SLACK_TEAM,
   )
   
   for setting_name, setting_value in staff_auth_settings.items():
       globals()[setting_name] = setting_value
   

6. Set Django to use the Slack auth backend whenever users are asked to log in.

   In your project's settings.py:

   LOGIN_URL = "staff_auth:slack-login"
   

7. Wire up the staff_auth and social_django URLs.

   In your project's top-level URLconf (urls.py file):

   urlpatterns = [
     # ...
     # Existing URL patterns
     # ...
   
     path("social/", include("social_django.urls", namespace="social")),
     path("staff-auth/", include("staff_auth.urls")),
   ]
   

8. Optional: Add pipelines.

   In your project's settings.py:

   SOCIAL_AUTH_PIPELINE = (
       "social_core.pipeline.social_auth.social_details",
       "social_core.pipeline.social_auth.social_uid",
       "social_core.pipeline.social_auth.auth_allowed",
       "social_core.pipeline.social_auth.social_user",
       "social_core.pipeline.user.get_username",
       "social_core.pipeline.user.create_user",
       "social_core.pipeline.social_auth.associate_user",
       "social_core.pipeline.social_auth.load_extra_data",
       "staff_auth.pipeline.promote_staffer_to_staff",
       "staff_auth.pipeline.promote_manager_to_superuser",
       "social_core.pipeline.user.user_details",
   )
   

   You can disable either or both of the staff_auth.pipeline classes listed above, but please take care to preserve the order seen here — re-ordering these pipelines could produce unintended and hard-to-debug consequences.

   NOTE: The behaviors of staff_auth.pipeline.promote_staffer_to_staff and staff_auth.pipeline.promote_manager_to_superuser are described in the "What's inside" section above.

   NOTE 2: If you're not using either staff_auth.pipeline class, skip this step and ensure your project's settings.py file has no SOCIAL_AUTH_PIPELINE value set.

9. Optional: Modify the URLs where users are bounced to when they successfully log in or log out.

   These are standard Django settings, and can take either URLs or named URL patterns (as you would pass to the {% url %} template tag).

   In your project's settings.py:

   LOGIN_REDIRECT_URL = "/my/url/pattern/"
   
   LOGOUT_REDIRECT_URL = "namespace:view-name"
   

   NOTE: For more information, see the Django documentation entries here and here.

Configuration

Setting	What it does
STAFF_AUTH_SLACK_KEY	The 'Client ID' from the Slack "app" you've connected to your workspace for authenticating users. Passed to Python Social Auth as SOCIAL_AUTH_SLACK_KEY.
STAFF_AUTH_SLACK_SECRET	The Client Secret from this Slack "app". Passed to Python Social Auth as SOCIAL_AUTH_SLACK_SECRET.
STAFF_AUTH_SLACK_TEAM	The name of the Slack workspace where your users have accounts. (A handy way of remembering this: it's also the subdomain of slack.com where users log in to use Slack itself.) Passed to Python Social Auth as SOCIAL_AUTH_SLACK_TEAM.

Copyright

© 2019–present POLITICO LLC