Linux - Running a Node Service (Forever)

linux_running_a_node_service_with_forever.md

#Linux - Running a Node Service (Forever) This is based on the excellent post at http://www.exratione.com/2013/02/nodejs-and-forever-as-a-service-simple-upstart-and-init-scripts-for-ubuntu/.

Forever is a useful tool for running a Node.js process with monitoring; it can be set to restart a failed process, and has a few other helpful features along the same lines. In this post you'll find a couple of exceedingly simple scripts for running a Node.js process as a service on Ubuntu using Forever.

##Install Forever Forever must be installed globally.

npm -g install forever

##Upstart Upstart is an alternative to using standard issue init scripts and is installed by default on Ubuntu. A script resides in the /etc/init folder and has a .conf file extension, e.g. /etc/init/my-application.conf. Run or check on the script and its process with the following commands:

start my-application
status my-application
restart my-application
stop my-application

###Upstart Script Most upstart scripts are set to automatically start and stop for specific run levels in the same way as init scripts. Here is an example Upstart script for a Node.js service running under Forever:

#!upstart
#
# An example upstart script for running a Node.js process as a service
# using Forever as the process monitor. For more configuration options
# associated with Forever, see: https://github.com/nodejitsu/forever
#
# You will need to set the environment variables noted below to conform to
# your use case, and should change the description.
#
description "Example upstart script for a Node.js process"

start on startup
stop on shutdown

# This line is needed so that Upstart reports the pid of the Node.js process
# started by Forever rather than Forever's pid.
expect fork

# The following environment variables must be set so as to define
# where Node.js and Forever binaries and the Node.js source code
# can be found.
#
# The example environment variables below assume that Node.js is
# installed into /home/node/local/node by building from source as outlined
# here:
# http://www.exratione.com/2011/07/running-a-nodejs-server-as-a-service-using-forever/
#
# It should be easy enough to adapt to the paths to be appropriate to a
#
# It should be easy enough to adapt to the paths to be appropriate to a
# package installation, but note that the packages available for Ubuntu in
# the default repositories are far behind the times. Most users will be
# building from source to get a more recent Node.js version.
#
# The full path to the directory containing the node and forever binaries.
# env NODE_BIN_DIR="/home/node/local/node/bin"
# Set the NODE_PATH to the Node.js main node_modules directory.
# env NODE_PATH="/home/node/local/node/lib/node_modules"
# The directory containing the application Javascript file.
# env APPLICATION_DIRECTORY="/home/node/my-application"
# The application start Javascript filename.
# env APPLICATION_START="start-my-application.js"
# Log file path.
# env LOG="/var/log/my-application.log"

env NODE_BIN_DIR="/usr/local/bin"
env NODE_PATH="/usr/local/lib/node_modules"
env APPLICATION_DIRECTORY="/var/www/api.nodenx.com"
env APPLICATION_START="server.js"
env LOG="/var/log/nodlog.log"
env NODE_ENV="production"

script
    # Add the node executables to the path, which includes Forever if it is
    # installed globally, which it should be.
    PATH=$NODE_BIN_DIR:$PATH

    # installed globally, which it should be.
    PATH=$NODE_BIN_DIR:$PATH
    # The minUptime and spinSleepTime settings stop Forever from thrashing if
    # the application fails immediately on launch. This is generally necessary to
    # avoid loading development servers to the point of failure every time
    # someone makes an error in application initialization code, or bringing down
    # production servers the same way if a database or other critical service
    # suddenly becomes inaccessible.
    exec forever --sourceDir $APPLICATION_DIRECTORY -a -l $LOG \
         --minUptime 5000 --spinSleepTime 2000 start $APPLICATION_START
end script

pre-stop script
    # Add the node executables to the path.
    PATH=$NODE_BIN_DIR:$PATH
    # Here we're using the pre-stop script to stop the Node.js application
    # process so that Forever is given a chance to do its thing and tidy up
    # its data. Note that doing it this way means that each application that
    # runs under Forever must have a different start file name, regardless of
    # which directory it is in.
    exec forever stop $APPLICATION_START >> $LOG
end script

You then need to register the service using:

update-rc.d nodlog defaults

This will use the default settings which is to start in runlevels 2-5 and stop in runlevels 0,1 and 6. You can specify exactly which runlevels you want if you wish.

##Run the Service at Startup You can run the service at startup by adding it to the /etc/rc.local file (/etc/rc.d/rc.local in Red Hat/CentOS).

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

service nodlog start

exit 0