Slack has been spamming my systemd journal logs with useless info level debug logs. I’ve tried starting slack with --silent and setting the log level to fatal using --logLevel, but the log spamming hasn’t stopped.
The solution is to filter these messages using rsyslog.
Create the following configuration under /etc/rsyslog.d/20-slack.conf:
# Drop info log messages from Slack
if $rawmsg contains "slack.desktop" then stop
Verify the configuration, then restart rsyslog:
$ sudo rsyslogd -N1
$ sudo systemctl restart rsyslog