Running tapeimgr in GUI mode on BitCurator / Ubuntu 18.04LTS (Bionic)

[bitsgalore]

The current launcher uses gksudo to run tapeimgr as root. But gksudo is not installed by default on BitCurator / Ubuntu 18.04LTS (Bionic). BitCurator does have the pkexec tool (which it uses to launch Guymager as root), but running the command:

pkexec tapeimgr

Results in this error:

_tkinter.TclError: no display name and no $DISPLAY environment variable

It seems that this not a bug, but a result of the pkexec/PolicyKit policy settings. See also:

https://groups.google.com/forum/#!topic/comp.lang.python/s4WMWIdkXMY

More on differences between pkexec and gksudo:

https://askubuntu.com/questions/78352/when-to-use-pkexec-vs-gksu-gksudo

And specifically on Python:

https://askubuntu.com/questions/288087/can-i-use-pkexec-in-a-python-script-or-a-desktop-file

[bitsgalore]

Additional info: updated everything to pkexec, but now for some reason the launcher script tapeimgr-pkexec is not extracted during pip install (even though it is in the tarball!).

[bitsgalore]

Missing pkexec fixed by:

1250313

Next problem:

• Now initial dir is /root
• Extraction freezes after 1st file; looks like something going wrong with the permissions (chown).

This happens because SUDO_UID, SUDO_GID and SUDO_USER are all undefined when running under pkexec!

Running pkexec with --user $USER at least results in a valid SUDO_USER BUT in that case we run as normal user and cannot access the tape device!

Apparently pkexec deliberately blocks most environment variables:

https://stackoverflow.com/questions/42960140/environment-variables-missing-when-executing-via-pkexec

Guymagr (which also uses pkexec) also uses /root as the starting dir.

A possible way to at least start tapeimgr with the user home dir as the default, would be to inject in a config file which is then read back.

[bitsgalore]

All works now.