Alternative to "borg mount -f" for debugging a script?

[Grunthos]

Have you checked borgbackup docs, FAQ, and open Github issues?

Yes

Is this a BUG / ISSUE report or a QUESTION?

QUESTION

Borg Version 1.1.9 on Debian 10.6.

Question:

I have a series of processes that run as follows (each process locks the other one from running):

PROCESS A -- regular rsync to local FS of a remote repository PROCESS B -- Mount the rsynced repository and back it up to another local repository

PROCESS B periodically crashes with "Transport endpoint is not connected"

I have found several people reporting this in the past and the general comment is that many things can cause it, the best diagnosis is to run borg mount -f.... Unfortunately this is an intermittent error, and when I rerun manually with -f it works. What I need is to log the mount output for each command until it fails.

How can I do this in a script that also needs to capture the return status of the mount command (in case it fails)? It also needs to wait until the mount is 'complete' before continuing, so a subprocess with the mount command is not a good fit.

Does borg have a logging option for borg mount? Standard output would be acceptable.