Django and Heroku Cookbook

Collection of snippets and scripts that solve certain problems when deploying Django apps to Heroku.

Scripts in the bin directory are post-compile hooks that are invoked by the heroku-buildpack-python's compile step. You can install them by copying the bin directory into the root directory of your Heroku application repository.

Installing NodeJS and Less compiler for static assets compilation in your Django app

Heroku provides a bunch of different buildpacks that target many popular platforms like Python, Ruby, NodeJS and Java web apps and backends. While this is great and allows you to deploy virtually anything with a simple git command, the out-of-the-box solutions offer a limited set of utilities that are available during the Slug compilation phase. In particular no NodeJS, NPM or LESS Compiler is available in the heroku-buildpack-python. This means that there is no straightforward way of compiling .less stylesheets during the app deployment.

Fortunately, the Python buildpack provides hooks for running pre-compile and post-compile scripts. This can be used for customizing the compilation step and running additional commands without the necessity of maintaining a separate fork of Heroku's buildpack. The only thing you need to do is to create a proper bin/post_compile bash script in the root directory of your application.

The bin and .heroku directories contain a set of scripts that can be used to install NodeJS/Less and invoke manage.py collectstatic and manage.py compress commands in your Django application:

• bin/post_compile
• bin/install_nodejs
• bin/install_less
• bin/run_collectstatic
• bin/run_compress
• .heroku/collectstatic_disabled

Just copy them over to your app reposiory and have your Less stylesheets compiled with an assets compressor like Django Compressor.

Note: the empty /.heroku/collectstatic_disabled file deactivates the default collectstatic build step that is part of the Heroku's buildpack. This will prevent the build script from doing unnecessary work that is already handled by the above scripts.

A note on hosting static files on Amazon S3. Remember to enable the environment variables if you are using django-storages and uploading static assets to S3:

heroku labs:enable user-env-compile

Automatic Django configuration and utilities for Heroku

django-herokuify is a Django settings helper that makes is very easy to configure database, cache, storage, email and other common services for your Django project running on Heroku:

import herokuify

from herokuify.common import *              # Common settings, SSL proxy header
from herokuify.aws import *                 # AWS access keys as configured in env
from herokuify.mail.mailgun import *        # Email settings for Mailgun add-on

DATABASES = herokuify.get_db_config()       # Database config
CACHES = herokuify.get_cache_config()       # Cache config for Memcache/MemCachier

See the project page for more information.

All in one

Django Modern Template is a project template for easy bootstrapping a Django project that can be deployed on Heroku.

Clean virtualenv

Heroku caches Python virtual environment and all installed packages between project deploys.

Since the CLEAN_VIRTUALENV flag has been removed from the buildpack, currently the only way to clean app cache is by changing the runtime.