check postfix and cyrus-imapd health with expect

mailsystem_check_restart.sh

#!/bin/bash

# Copyright (C) <year>  <name of author>
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <https://www.gnu.org/licenses/>.
#
#    mailsystem_check_restart.sh uses expect to establish a connection to cyrus-imapd
#    and postfix with openssl. If the services do not react as expected, they are restarted.
#    The script should work with any SMTP and IMAP server.
#
#    Author: Henning Hollermann - laclaro@mail.com - 2020

do_restart_cyrus() {
    echo "No reply from cyrus on port 993. Restarting cyrus-imapd."
    /usr/sbin/service cyrus-imapd restart
    if [ $? != 0 ]; then
        echo "cyrus-imapd hangs, killing it by force..."
        /usr/bin/killall -9 cyrus-master
        /usr/sbin/service cyrus-imapd restart
    fi
    return 0
}

do_restart_postfix() {
    echo "No reply from postfix on port 25. Restarting cyrus-imapd."
    /usr/sbin/service postfix restart
    return 0
}

check_cyrus() {
/usr/bin/expect -c '
set server hollermann.eu
set port 993
set timeout 5
spawn openssl s_client -crlf -connect $server:$port
expect {
    timeout {
        puts stdout "timeout while connecting to $server"; 
        exit 1;
    }
    "* OK" { exit 0; }
    eof { exit 1; }
}
  }' > /dev/null
return $?
}

check_postfix() {
/usr/bin/expect -c '
set timeout 5
set server hollermann.eu
set port 25
spawn openssl s_client -starttls smtp -connect $server:$port
expect {
    timeout {
        puts stdout "timeout while connecting to $server"; 
        exit 1;
    }
    "250 DSN" { exit 0; }
    eof { exit 1; }
}' > /dev/null
return $?
}

if [ "x$1" == "xforce" ]; then
    do_restart_cyrus
    do_restart_postfix
else
    echo "Info: Use \"$0 force\" to force the restart of cyrus-imapd and postfix"
    check_cyrus || do_restart_cyrus
    check_postfix || do_restart_postfix
fi