chore: Remove wrapper script for fail2ban service (#3032)

* chore: Remove the wrapper script for `fail2ban`

- This does not appear necessary. The server can be run with foreground mode.
- `daemons-stack.sh` removal of the socket can be handled by the fail2ban server when using the `-x` option.

* chore: Remove `touch /var/log/auth.log`

These were both added as supposed fixes in 2016 for the then Ubuntu 2014 base image.

Removing them causes no failures in tests.

* fix: Install optional python packages for `fail2ban`

These have barely any overhead in layer weight. The DNS package may provide some QoL improvements, while the `pyinotify` is a better alternative than polling logs to check for updates.

We have `gamin` package installed but `fail2ban` would complain in the log that it was not able to initialize the module for it. There only appears to be a `python-gamin` dependent on EOL python 2, no longer available from Debian Bullseye.

Dockerfile

@@ -240,7 +240,6 @@ RUN <<EOF
   rm -rf /usr/share/locale/*
   rm -rf /usr/share/man/*
   rm -rf /usr/share/doc/*
-  touch /var/log/auth.log
   update-locale
   rm /etc/postsrsd.secret
   rm /etc/cron.daily/00logwatch

target/scripts/build/packages.sh

@@ -153,6 +153,7 @@ function _install_fail2ban
   local FAIL2BAN_GPG_PUBLIC_KEY_SERVER='hkps://keyserver.ubuntu.com'
 
   _log 'debug' 'Installing Fail2ban'
+  apt-get "${QUIET}" --no-install-recommends install python3-pyinotify python3-dnspython
 
   gpg --keyserver "${FAIL2BAN_GPG_PUBLIC_KEY_SERVER}" --recv-keys "${FAIL2BAN_GPG_PUBLIC_KEY_ID}" 2>&1
 

target/scripts/startup/daemons-stack.sh

@@ -56,11 +56,6 @@ function _start_daemon_postgrey
 
 function _start_daemon_fail2ban
 {
-  touch /var/log/auth.log
-
-  # delete fail2ban.sock that probably was left here after container restart
-  [[ -e /var/run/fail2ban/fail2ban.sock ]] && rm /var/run/fail2ban/fail2ban.sock
-
   _default_start_daemon 'fail2ban'
 }
 

target/scripts/wrapper/fail2ban-wrapper.sh

@@ -1,31 +0,0 @@
-#!/bin/bash
-
-# You cannot start fail2ban in some foreground mode and
-# it's more or less important that docker doesn't kill
-# fail2ban and its chilren if you stop the container.
-#
-# Use this script with supervisord and it will take
-# care about starting and stopping fail2ban correctly.
-#
-# supervisord config snippet for fail2ban-wrapper:
-#
-# [program:fail2ban]
-# process_name = fail2ban
-# command = /path/to/fail2ban-wrapper.sh
-# startsecs = 0
-# autorestart = false
-#
-
-trap "/usr/bin/fail2ban-client stop" SIGINT
-trap "/usr/bin/fail2ban-client stop" SIGTERM
-trap "/usr/bin/fail2ban-client reload" SIGHUP
-
-/usr/bin/fail2ban-client start
-sleep 5
-
-# wait until fail2ban is dead (triggered by trap)
-while kill -0 "$(< /var/run/fail2ban/fail2ban.pid)"
-do
-  sleep 5
-done
-

target/supervisor/conf.d/supervisor-app.conf

@@ -40,7 +40,7 @@ autostart=false
 autorestart=true
 stdout_logfile=/var/log/supervisor/%(program_name)s.log
 stderr_logfile=/var/log/supervisor/%(program_name)s.log
-command=/usr/local/bin/fail2ban-wrapper.sh
+command=/usr/bin/fail2ban-server -xf start
 
 [program:opendkim]
 startsecs=0