Heroku Buildpack: Python

This is the official Heroku buildpack for Python apps, powered by Pipenv, 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.

Python packages with C dependencies that are not available on the stack image are generally not supported, unless manylinux wheels are provided by the package maintainers (common). For recommended solutions, check out this article for more information.

See it in Action

Deploying a Python application couldn't be easier:

$ ls
Pipfile		Pipfile.lock	Procfile	web.py

$ heroku create --buildpack heroku/python

$ git push heroku master
…
-----> Python app detected
-----> Installing python-3.6.6
-----> Installing pip
-----> Installing requirements with Pipenv 2018.5.18…
       ...
       Installing dependencies from Pipfile…
-----> Discovering process types
       Procfile declares types -> (none)

A Pipfile or requirements.txt 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 in your Pipfile:

[requires]
python_version = "2.7"

Or, more specifically:

[requires]
python_full_version = "2.7.15"

Or, with a runtime.txt file:

$ cat runtime.txt
python-2.7.15

Runtime options include:

• python-3.7.0
• python-3.6.6
• python-2.7.15

Tests

The buildpack tests use Docker to simulate Heroku's stack images.

To run the test suite:

make test

Or to test in a particular stack:

make test-heroku-18
make test-heroku-16

The tests are run via the vendored shunit2 test framework.