Heroku Buildpack: Python

This is the official Heroku buildpack for Python apps, powered by pip and other excellent software.

Recommended web frameworks include Django and Flask. The recommended webserver is Gunicorn. There are no restrictions around what software can be used (as long as it's pip-installable). Web processes must bind to $PORT, and only the HTTP protocol is permitted for incoming connections.

Some Python packages with obscure C dependencies (e.g. scipy) are not compatible.

See it in Action

Deploying a Python application couldn't be easier:

$ ls
Procfile  requirements.txt  web.py

$ heroku create --buildpack heroku/python

$ git push heroku master
...
-----> Python app detected
-----> Installing python-2.7.11
     $ pip install -r requirements.txt
       Collecting requests (from -r requirements.txt (line 1))
         Downloading requests-2.9.1-py2.py3-none-any.whl (501kB)
       Installing collected packages: requests
       Successfully installed requests-2.9.1
       
-----> Discovering process types
       Procfile declares types -> (none)

A requirements.txt file must be present at the root of your application's repository.

You can also specify the latest production release of this buildpack for upcoming builds of an existing application:

$ heroku buildpacks:set heroku/python

Specify a Python Runtime

Specific versions of the Python runtime can be specified with a runtime.txt file:

$ cat runtime.txt
python-3.5.1

Runtime options include:

• python-2.7.11
• python-3.5.1
• pypy-5.0.1 (unsupported, experimental)

Other unsupported runtimes are available as well. Use at your own risk.

Add custom environment variables

You may need to add custom environment variables during the build. They can be specified with a .heroku-env file:

$ cat .heroku-env
PYTHONPATH=/app/.heroku/python/lib/python3.4/site-packages:/app/.heroku/miniconda/envs/condaenv/lib/python3.4/site-packages:$PYTHONPATH

They will be exported before installing packages with pip, and before the Django Collectstatic runner.