User mapping query

[clbarnes]

I'm using an image based on this one, and am struggling with file permissions.

If do not include a --user argument in docker run, then the artifacts produced by the image are owned by root rather than my local user. However, if I include --user "$(id -u):$(id -g)", then I get a "permission denied" error from tectonic (when there are no root-owned files in the local directory, which is mounted as a volume).

Any thoughts on why this might be and how to work around it?

[PHPirates]

Good question, I don't know the answer. I'd have thought that if you mount /etc/passwd tectonic has all the info it needs, because the user owning the file is the same as the one logged in, but apparently not. The error message does not say what permissions it is missing, maybe you can raise an issue at the Tectonic repo to find more logging.

[WtfJoke]

Sorry to disappoint, but I dont know the answer neither 🙈 . But I could also do some tests.

Can you also reproduce this with the alpine image?

[clbarnes]

Here's a test repo: https://github.com/clbarnes/tectonic-docker-permissions . It has just commands for all of the orders of operations.

While the simple solution would seem to be "don't mix dockerised and non-dockerised builds", it's not quite so simple if e.g. you're using an IDE which runs builds on its own in the background for smart highlighting purposes.