mirror of
https://github.com/kennethreitz/heroku-buildpack-python.git
synced 2026-06-05 23:10:16 +00:00
Noah Zoschke
45 lines
1.7 KiB
Markdown
45 lines
1.7 KiB
Markdown
Python Language Pack
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====================
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The Python Language Pack (PLP) is a language pack for running Python and Django
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apps on Heroku.
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If `requirements.txt` is present, the PLP considers the directory a Python app
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with packages to install via pip.
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Furthermore, if `${project}/settings.py` is present, the PLP considers the
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directory a Python/Django app, and patches `settings.py` to parse the Heroku
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DATABASE_URL config vars. It then sets default process types to use the Django
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web server and console.
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Compile Hooks
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-------------
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The PLP uses a Makefile for user-controlled hooks into slug compilation. If
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present, the `make environment` rule will be eval'd in the compile script, allowing
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user-defined exports.
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A sample Makefile to force a re-build of every pip package is:
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environment:
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export PIP_OPTS=--upgrade
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(<a href="https://github.com/heroku/language-pack-python/raw/master/test/canary_django/Makefile">raw file</a>)
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Django settings.py
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------------------
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The PLP injects code into settings.py to alias every Heroku database URL
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config var. Every variable of the format ${NAME}_URL => postgres:// will be
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added to the settings.DATABASES hash.
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On an app with both a shared SHARED_DATABASE_URL and a dedicated
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HEROKU_POSTGRESQL_RED_URL that is promoted to DATABASE_URL, settings will look
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like:
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{
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'DATABASE': {'ENGINE': 'psycopg2', 'NAME': 'dedicated', ...},
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'HEROKU_POSTGRESQL_RED': {'ENGINE': 'psycopg2', 'NAME': 'dedicated', ...},
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'SHARED': {'ENGINE': 'psycopg2', 'NAME': 'shared', ...},
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'default': {'ENGINE': 'psycopg2', 'NAME': 'dedicated', ...},
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}
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These aliases can be referenced and further modified at the end of the settings file.
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