Freezing requirements with pip-tools#

Create a requirements.in#

The requirements.in file contains your un-pinned requirements. Mine ended up looking like this:

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Django~=4.0
2
gunicorn
3
whitenoise
4
psycopg2-binary
5
dj-database-url
6
pytest-django
7
django-extensions
8
django-htmx
9
pytz
10
bs4
11
httpx
12
sentry-sdk
13
pytest-httpx
14
ics==0.7

Django~=4.0 means version Django 4.0 or higher, but less than 4.1. I pinned it like this because I saw a warning from django-extensions:

django.utils.deprecation.RemovedInDjango41Warning: 'django_extensions' defines default_app_config = 'django_extensions.apps.DjangoExtensionsConfig'.

I’m pinning ics to the exact version 0.7 due to a broken test I experienced with more recent versions.

Compiling requirements.txt from requirements.in#

The pip-compile command runs against a requirements.in file and writes requirements.txt in the current directory with pinned versions of the packages.

You have to pip install pip-tools first to get that command.

I ran it like this:

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pip-compile --upgrade --generate-hashes requirements.in

The --upgrade option here causes it to check PyPI for the maximum version of each package that matches the lines in requirements.in - without this it may settle for packages that are currently in your local cache.

--generate-hashes adds hashes to the generated file, as a security measure.

I then committed both requirements.in and requirements.txt to the repo.

Here’s the generated requirements.txt.

Updating requirements locally with pip-sync#

The other tool installed by pip-tools is pip-sync. It’s useful for keeping your local development environment updated with the exact packages from requirements.txt.

Run it like this:

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pip-sync

It will uninstall and reinstall packages in your virtual environment until they exactly match requirements.txt.