I added a new mini project to github: msmtpq_notify .
The following is the content of the README file:
When using msmtpq in front of msmtp all failed connection attempts to the mailserver results in the mail being silently added to the queue.
While this is a desired behaviour in most cases it may be fatal when msmtp or the mail server is misconfigured. In this case msmtp may always fails and mail never becomes delivered.
This script is a wrapper script which can be run itself in front of msmtQ.
After the call to msmtpQ it informs the user about the number of entries in the
queue. It does so by checking the queue before and after the call to msmtpQ
with msmtpq -d.
So the user has the chance to be informed if something still hangs in the queue
an can manually intervent. Alternatively the latest versions of msmtpq also
run/flush the queue on the next call to msmtpQ.
msmtpq_notify.py uses the the deskop notification daemon which is available in
most modern Linux desktop environments. To be able to communicate with the
daeamon you need to install notify-send before. In Ubuntu it is available in
the package libnotify-bin.
msmtpq_notify.py passes stdin and all arguments over to msmtpq and returns its
exit code back (although the last version seems to always return with 0, even
if msmtp reported some error). For debugging purposes create a symlink
msmtpq_notify_debug.py. If called as msmtpq_notify_debug.py it will output
additional traces.