Save output as user not root? + harmless errors?

[polarathene]

I've tried to print from a local dev server(provided the host network and port), the delay is to get around a toast notification when the page is loaded(BrowserSync based). This all works good.

$ docker run --net="host" --rm -v $(pwd):/converted/ arachnysdocker/athenapdf athenapdf http://localhost:3000 --delay 5000
Xlib:  extension "RANDR" missing on display ":99".
Xlib:  extension "RANDR" missing on display ":99".
libudev: udev_has_devtmpfs: name_to_handle_at on /dev: Operation not permitted
Converted 'http://localhost:3000' to PDF: '2bf0fa1d7db9ecd60b2c436978513d3c1c5536a8.pdf'
PDF Conversion: 5517.037ms

$ ls -la
-rw-r--r--   1 root root  167730 Nov 11 18:53 2bf0fa1d7db9ecd60b2c436978513d3c1c5536a8.pdf

The errors don't seem to be causing any problems, the PDF is written, it's just done so as the root user(due to running via Docker I guess). The file doesn't show up in my file browser, I have to open an instance of the file browser as root. A docker setting can get around this I guess?(if this isn't the case for you it could be due to my distro/package settings for docker too, I'm in a group called docker).

EDIT: Just saw the libudev suppression note here. Still looking into the file ownership issue, seems using gosu with an entrypoint script should do the trick.