Installation

  1. Make sure you have gcloud tools installed, and you've installed the Datastore Emulator
  2. For local development, you'll want to pip install gcloud-tasks-emulator and gcloud-storage-emulator from PyPi
  3. Create a Django project, add app.yaml and main.py to the root. Make sure Django 2.2+ is in your project and importable.
  4. Add a requirements.txt to the root of your project, add djangae to it and install in your environment
  5. Add 'djangae' to INSTALLED_APPS, and probably also 'djangae.tasks'. This must come before any django apps.
  6. We also recommend that you:
    • Add 'djangae.contrib.security' to INSTALLED_APPS'.
    • Add 'djangae.contrib.security.middleware.AppEngineSecurityMiddleware' to MIDDLEWARE_CLASSES.
  7. At the top of your settings.py, insert the following line to setup some default settings:
from djangae.settings_base import *

In app.yaml add the following handlers:

runtime: python37

handlers:
# This configures Google App Engine to serve the files in the app's static
# directory.
- url: /static
  static_dir: static/

# This handler routes all requests not caught above to your main app. It is
# required when static routes are defined, but can be omitted (along with
# the entire handlers section) when there are no static files defined.
- url: /.*
  script: auto

Make your manage.py look something like this:

#!/usr/bin/env python
import os
import sys

if __name__ == '__main__':
    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'myapp.settings')
    try:
        from django.core.management import execute_from_command_line
    except ImportError as exc:
        raise ImportError(
            "Couldn't import Django. Are you sure it's installed and "
            "available on your PYTHONPATH environment variable? Did you "
            "forget to activate a virtual environment?"
        ) from exc

    from djangae.sandbox import start_emulators, stop_emulators

    try:
        # Start all emulators, persisting data if we're not testing
        start_emulators(persist_data="test" not in sys.argv)
        execute_from_command_line(sys.argv)
    finally:
        # Stop all emulators
        stop_emulators()

Use the Django WSGI handler in your main.py, something like

from .wsgi import application
app = application

It is recommended that for improved security you add djangae.contrib.security.middleware.AppEngineSecurityMiddleware as the first of your middleware classes. This middleware patches a number of insecure parts of the Python and App Engine libraries and warns if your Django settings aren't as secure as they could be.

Deployment

Deploying your application is the same as deploying any Google App Engine project.

Cache Backend

By default, Djangae uses FileBasedCache storing data in .cache/ in your local env and in /tmp when deployed to GAE. This provides an in-memory caching system (/tmp is an in-memory filesystem), which is not shared across instances. If you need cross-instances cache we recommend using Memorystore for Redis with django-redis-cache. Make sure you configure VPC for your project to allow access to the redis instance from your GAE standard environment app. Your configuration should look something like this:

# ...
from djangae.settings_base import *

CACHES = {
    'default': {
        'BACKEND': 'redis_cache.RedisCache',
        'LOCATION': '10.237.7.251:6379',
    },
}

System views

Djangae ships handlers for various system functions. To enable them include djangae.urls in your url patterns. E.g.

urlpatterns = [
    path('_ah/', include('djangae.urls')),
]

The _ah/ path is important as the views handle the built-in App Engine requests to /_ah/warmup, /_ah/start, and /_ah/stop.

Additionally Djangae implements a view at /_ah/clearsessions to handle clearing expired Django sessions from the database. You should configure cron to post to this URL (see sessions.md)