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Setting Up Mailcatcher as a Service in Debian/Ubuntu

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Setting Up Mailcatcher as a Service in Debian/Ubuntu

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I've recently been changing joind.in's Vagrant system to use Debian and one issue I came across was getting Mailcatcher to start on boot and integrate property with the service command.

To do this, I created an init script which is based off the skeleton and then stored this in /etc/init.d and then ranupdate-rc.d mailcatcher defaults to set up the correct links in the various rc.d directories.

This is the init script:

/etc/init.d/mailcatcher:

#! /bin/sh
### BEGIN INIT INFO
# Provides:          mailcatcher
# Required-Start:    $remote_fs $syslog
# Required-Stop:     $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Example initscript
# Description:       This file should be used to construct scripts to be
#                    placed in /etc/init.d.
### END INIT INFO

# Do NOT "set -e"

# PATH should only include /usr/* if it runs after the mountnfs.sh script
PATH=/sbin:/usr/sbin:/bin:/usr/bin:/usr/local/rvm/gems/ruby-1.9.3-p547/bin
DESC="Super simple SMTP server"
NAME=mailcatcher
DAEMON=/usr/local/rvm/wrappers/default/$NAME
DAEMON_ARGS=" --http-ip 0.0.0.0"
PIDFILE=/var/run/$NAME.pid
SCRIPTNAME=/etc/init.d/$NAME

# Exit if the package is not installed
[ -x "$DAEMON" ] || exit 0

# Read configuration variable file if it is present
[ -r /etc/default/$NAME ] && . /etc/default/$NAME

# Load the VERBOSE setting and other rcS variables
. /lib/init/vars.sh

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.2-14) to ensure that this file is present
# and status_of_proc is working.
. /lib/lsb/init-functions

#
# Function that starts the daemon/service
#
do_start()
{
    # Return
    #   0 if daemon has been started
    #   1 if daemon was already running
    #   2 if daemon could not be started
    start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON --test > /dev/null \
        || return 1
    start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON -- \
        $DAEMON_ARGS \
        || return 2
    # Add code here, if necessary, that waits for the process to be ready
    # to handle requests from services started subsequently which depend
    # on this one.  As a last resort, sleep for some time.
     
    # Create the PIDFILE
    pidof mailcatcher >> $PIDFILE
}

#
# Function that stops the daemon/service
#
do_stop()
{
    # Return
    #   0 if daemon has been stopped
    #   1 if daemon was already stopped
    #   2 if daemon could not be stopped
    #   other if a failure occurred
    
    if [ -f "$PIDFILE" ]
    then
        kill `cat $PIDFILE`
        rm -f $PIDFILE
        return 0
    else
        return 1
    fi
}

#
# Function that sends a SIGHUP to the daemon/service
#
do_reload() {
    #
    # If the daemon can reload its configuration without
    # restarting (for example, when it is sent a SIGHUP),
    # then implement that here.
    #
    start-stop-daemon --stop --signal 1 --quiet --pidfile $PIDFILE --name $NAME
    return 0
}

case "$1" in
  start)
    [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME"
    do_start
    case "$?" in
        0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
        2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
    esac
    ;;
  stop)
    [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
    do_stop
    case "$?" in
        0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
        2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
    esac
    ;;
  status)
    status_of_proc "$DAEMON" "$NAME" && exit 0 || exit $?
    ;;
  #reload|force-reload)
    #
    # If do_reload() is not implemented then leave this commented out
    # and leave 'force-reload' as an alias for 'restart'.
    #
    #log_daemon_msg "Reloading $DESC" "$NAME"
    #do_reload
    #log_end_msg $?
    #;;
  restart|force-reload)
    #
    # If the "reload" option is implemented then remove the
    # 'force-reload' alias
    #
    log_daemon_msg "Restarting $DESC" "$NAME"
    do_stop
    case "$?" in
      0|1)
        do_start
        case "$?" in
            0) log_end_msg 0 ;;
            1) log_end_msg 1 ;; # Old process is still running
            *) log_end_msg 1 ;; # Failed to start
        esac
        ;;
      *)
        # Failed to stop
        log_end_msg 1
        ;;
    esac
    ;;
  *)
    #echo "Usage: $SCRIPTNAME {start|stop|restart|reload|force-reload}" >&2
    echo "Usage: $SCRIPTNAME {start|stop|status|restart|force-reload}" >&2
    exit 3
    ;;
esac

:

As you can probably tell, it's very obviously a tweaked version of /etc/init.d/skeleton, but there are some important changes:

Path to binary
As Mailcatcher is a ruby app, the correct path to the binary is actually/usr/local/rvm/wrappers/default/mailcatcher which is not where which tells you it is. I suspect that my lack of knowledge about Ruby environments is showing…

do_start()
The do_start() function calls through to start-stop-daemon to start mailcatcher. However this doesn't create a pid file in /var/run for us, so we create it ourselves using:

pidof mailcatcher >> $PIDFILE

do_stop()
Mailcatcher is intended to be stopped by pressing the Quit button in the HTML interface, so the default code inskeleton doesn't work. I rewrote it to simply kill the process if the pid file exists:

if [ -f "$PIDFILE" ]
    then
        kill `cat $PIDFILE`
        rm -f $PIDFILE
        return 0
    else
        return 1
    fi

That's it. The most important thing about these changes is that service mailcatcher status now works as expected and so Puppet's ensure => 'running' test actually works correctly.


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Published at DZone with permission of Rob Allen, DZone MVB. See the original article here.

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