Run as Service/Daemon

A daemon is a computer program that runs continuously as a background process.

After Bots installation there are no service/daemon processes active. This is recommended for a production environment. Bots has several parts that you may want to run as services/daemons:

  • bots-webserver.py
  • bots-jobqueueserver.py (bots >= 3.0.0, is optional)
  • bots-dirmonitor.py (bots >= 3.0.0, is optional)

Note

bots-engine itself is not a daemon process; bots-engine is best scheduled.

How these daemons are created and managed depends on the operating system being used:

Linux Daemons

Below are some examples that run bots-webserver or jobqueserver as a daemon:

Example 1

I have been starting bots-webserver on my Linux (CentOS) servers via an entry in rc.local and wanted to provide a means to gracefully shut down the process on reboot. There have been other examples of init scripts posted which do the trick, but I wanted to put something together that conformed to LSB. I took an example script I found online and configured it for the bots.webserver process. Since CentOS doesn’t handle pid files correctly when using LSB functions, I tweaked it to work around the issue, and it should work on most distributions without a lot of modification

### BEGIN INIT INFO
# Provides:          bots-webserver
# Required-Start:    $remote_fs $network
# Required-Stop:     $remote_fs $network
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: BOTS webserver daemon
# Description:       BOTS webserver daemon
### END INIT INFO

# Using the lsb functions to perform the operations.
. /lib/lsb/init-functions
# Process name ( For display )
NAME=bots-webserver
# Daemon name, where is the actual executable
DAEMON=/usr/bin/bots-webserver.py
# pid file for the daemon
PIDFILE=/var/run/bots-webserver.pid
# Arguments for the daemon
ARGS="> /dev/null 2>&1 &"

# If the daemon is not there, then exit.
test -x $DAEMON || exit 5

case $1 in
 start)
  # Checked the PID file exists and check the actual status of process
  if [ -e $PIDFILE ]; then
   pidofproc -p $PIDFILE $DAEMON && status="0" || status="$?"
   # If the status is SUCCESS then don't need to start again.
   if [ $status = "0" ]; then
    log_success_msg "$NAME process is already running"
    exit # Exit
   fi
  fi
  # Start the daemon.
  # Start the daemon with the help of start-stop-daemon
  # Log the message appropriately
  if start_daemon -p $PIDFILE $DAEMON $ARGS; then
   # For older LSB functions that don't handle -p argument correctly (i.e. CentOS)
   if [ ! -e $PIDFILE ]; then
    pidofproc $DAEMON > $PIDFILE
   fi
   log_success_msg "Starting the process $NAME"
  else
   log_failure_msg "Failed to start the process $NAME"
  fi
  ;;
 stop)
  # Stop the daemon.
  if [ -e $PIDFILE ]; then
   pidofproc -p $PIDFILE $DAEMON > /dev/null && status="0" || status="$?"
   if [ "$status" = 0 ]; then
    killproc -p $PIDFILE $DAEMON
    /bin/rm -f $PIDFILE
    log_success_msg "Stoppping the $NAME process"
   fi
  else
   log_warning_msg "$NAME process is not running"
  fi
  ;;
 restart)
  # Restart the daemon.
  $0 stop && sleep 2 && $0 start
  ;;
 status)
  # Check the status of the process.
  if [ -e $PIDFILE ]; then
   pidofproc -p $PIDFILE $DAEMON > /dev/null && log_success_msg "$NAME process is running" && exit 0 || exit $?
  else
   log_warning_msg "$NAME process is not running"
  fi
  ;;
 reload)
  # Reload the process. Basically sending some signal to a daemon to reload
  # it configurations.
  if [ -e $PIDFILE ]; then
   killproc -p $PIDFILE $DAEMON -signal USR1
   log_success_msg "$NAME process reloaded successfully"
  else
   log_failure_msg "$PIDFILE does not exists"
  fi
  ;;
 \*)
  # For invalid arguments, print the usage message.
  echo "Usage: $0 {start|stop|restart|reload|status}"
  exit 2
  ;;
esac

Example 2

Works on debian/ubuntu servers and uses start-stop-daemon.

#! /bin/sh
#
# uses 'start-stop-daemon' , which is used in debian/ubuntu
#
NAME=bots-webserver
PIDFILE="/var/run/$NAME.pid"
DAEMON="/usr/local/bin/bots-webserver.py"
DAEMON_ARGS="-cconfig"

case "$1" in
    start)
        echo "Starting "$NAME" "
        start-stop-daemon --start --verbose --background --pidfile $PIDFILE --make-pidfile --startas $DAEMON -- $DAEMON_ARGS
        ;;
    stop)
        echo "Stopping "$NAME" "
        start-stop-daemon --stop --verbose --pidfile $PIDFILE
        rm -f $PIDFILE
        ;;
    restart)
        echo "Restarting "$NAME" "
        start-stop-daemon --stop --verbose --pidfile $PIDFILE
        rm -f $PIDFILE
        sleep 1
        start-stop-daemon --start --verbose --background --pidfile $PIDFILE --make-pidfile --startas $DAEMON -- $DAEMON_ARGS
        ;;
    \*)
        echo "Usage: ""$(basename "$0")"" {start|stop|restart}"
        echo "    Starts the bots webserver as a daemon."
        echo "    Bots-webserver is part of bots open source edi translator (http://bots.sourceforge.net)."
        exit 1
        ;;
esac

exit 0

Example 3

A script for starting the job queue server as a upstart in Ubuntu. Add the following file: /etc/init/bots-jobqueue.conf

description "Bots Job queue server"
author "bots@yourmail.com"

start on runlevel [2345]
stop on runlevel [!2345]

respawn

exec bots-jobqueueserver.py

Windows Services

If running Bots on a Windows server, you can create services to keep the important background processes running. This is the equivalent of a daemon process in Linux.

Prerequisites

  • srvany.exe - This is a Microsoft utility included in the Windows Server Resource Kit Tools.
  • sc.exe - The SC command is included by default in most Windows installations and is also available in the resource kit.
  • Python and Bots are already installed and working, of course!

Procedure

  • Copy srvany.exe to C:WindowsSystem32.

  • Open a command prompt and enter the following commands, according to the service required. Note: position of equal signs and spaces must be exactly as shown.

    sc create "Bots Webserver" binPath= "C:\Windows\System32\srvany.exe" start= auto DisplayName= "Bots Webserver"
sc description "Bots Webserver" "This is the webserver for Bots EDI translator."

    sc create "Bots Job Queue" binPath= "C:\Windows\System32\srvany.exe" start= auto DisplayName= "Bots Job Queue"
sc description "Bots Job Queue" "Provides job queue and launch functionality for Bots EDI Translator"

    sc create "Bots Directory Monitor" binPath= "C:\Windows\System32\srvany.exe" start= auto DisplayName= "Bots Directory Monitor"
sc description "Bots Directory Monitor" "Monitors one or more directories for new files and creates Bots jobs to process them"

  • Run regedit and navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\<Service Name>

  • In the right hand pane of regedit, right click, New, Key, call it Parameters.

  • Click the new Parameters key to select it.

  • In the right hand pane, right click, New, String value, call it Application.

  • Double click Application, enter the command to run the required Bots script. This will vary according to your installed location and Bots version, eg.

    C:\Python27\python.exe C:\Python27\Scripts\bots-webserver.py
C:\Python27\python.exe C:\Python27\Scripts\bots-jobqueueserver.py
C:\Python27\python.exe C:\Python27\Scripts\bots-dirmonitor.py

  • Run services.msc to start/stop/configure your new services.

If any of the above doesn’t make sense to you, I have created a small free utility program to do it all. This is a general purpose program for creating services. My service configuration for Bots is included; you may need to edit the paths to suit your installation. You can download the program from here.

../_images/CreateWinSrv1.png

Reference links