Track system log for error messages and show desktop notifications (Linux, systemd-journal, libnotify)

monitor_journal.sh

#!/bin/bash
##
## Description:
##   Track system log for error messages and show desktop notifications.
##

## filter messages that shouldn't show a notification
filter() {
    grep --line-buffered -vE \
        -e ': gkr-pam: unable to locate daemon control file$' \
        -e ' pulseaudio\S+: ALSA woke us up to \S+ new data \S+ the device, but there was actually nothing to \S+.$' \
        -e ' pulseaudio\S+: Most likely this is a bug in the ALSA driver .snd_hda_intel.. Please report this issue to the ALSA developers.$' \
        -e ' pulseaudio\S+: We were woken up with POLL\S+ set -- however a subsequent snd_pcm_avail.. returned 0 or another value < min_avail.$' \
        -e ' libvirtd\S+: internal error: End of file from qemu monitor$' \
        ###
}

## filter messages that should only show a 'normal' notification instead of 'critical'
not_critical() {
    ! grep -q -vE \
        -e 'kernel: \[drm:amdgpu_gem_va_ioctl \[amdgpu\]\] \*ERROR\* Couldn.t update BO_VA \(-16\)$' \
        ###
}

#------------------------------------------------------------------------------

if pidof -o "$$" -x "$0" > /dev/null; then
    echo "${0##*/}: An instance of this script is already running!"
    exit 1
fi

journalctl -f -q -b -perr |
filter |
while read -r line; do
    buffer="$line"
    # collect a sequence of messages over one second into a single desktop notification
    while read -t1 line; do
        buffer="$buffer"$'\n'"$line"
    done
    # echo "-->"
    # echo "$buffer"
    # echo "<--"
    if not_critical <<< "$buffer"; then
        notify-send -t 7000 -i dialog-warning -u normal -- "Error!" "$buffer"
    else
        notify-send -t 0 -i dialog-error -u critical -- "Error!" "$buffer"
    fi
done