Running uv in dev containers & github actions

Over the weekend I spent some time getting uv running on to see what the hubbub was about. As it turns out, it was harder than expected because of permission issues inside of dev containers & github actions.

The existing documentation on the uv github repo as well as docker instructions from ryxcommar’s blog are not pointed at my scenario, which is running it in a docker image and in CI. This blog post is up so if others run into this issue, they can find it and add it to their set up as well.

How to run uv in a dev container

Since we are using system python with uv, we need to tweak some settings in our dev container. There are two changes to make: (1) run as root user, and (2) add ““chmod 777 /tmp to your postCreateCommand. In your devcontainer.json, add or modify the following lines:

"postCreateCommand": "chmod 777 /tmp",
"remoteUser": "root"

Then you can run `uv pip install --system -r requirements.txt in your devcontainer to add libraries as needed.

How to run uv in Github Actions

Now that we are using system python in our dev container, we also need to add one step to get the perms setup in CI. And that step is to add a python setup step in the Github action before running uv.

      - name: Set up Python
        uses: actions/setup-python@v2
          python-version: '3.11'

Using the “actions/setup-python@v2” github action step will set up your runtime environment to properly interact with `uv pip install --system. Shout out to Charlie, of course, who very helpfully PR’d this into the mdsinabox repo.

Hope you find this useful! Please feel free to drop me a line on twitter @matsonj if you have any comments or feedback.