This presentation is Part 29 of the EWD 3 Training Course. It explains how to run QEWD Node.js as a background service on Windows and Linux systems, instead of running it as a foreground process in a Command Prompt or Terminal window.

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EWD 3 Training Course
Part 29
Running QEWD as a Service
Rob Tweed
Director, M/Gateway Developments Ltd
Twitter: @rtweed

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The QEWD Node.js process
• So far we've run it in a Command Prompt
or Terminal window
– This OK for demonstration
– But not for production
• It needs to run as a service
– Automatically start at boot time
– Restart on error
– Pipe console.log to a log file

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Running QEWD as a Service
• Different approaches needed for
– Windows
– Linux
• Many different options available, but the
following are two that seem to work well

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Running QEWD as a Service
• Windows:
– NSSM
• Linux
– PM2

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Windows: NSSM
• http://nssm.cc/
• Free Service Manager for Windows
• Works very well with Node.js and QEWD
• Click download and get the latest version
– 2.24 (at time of writing these notes)

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Install NSSM
• Drill down into the downloaded file
– Downloads/nssm-2.24.zip
• Find the /win64 directory
– Downloads/nssm-2.24.zip/nssm-2.24/win64/nssm.exe
• Copy nssm.exe to a directory that is
already in your PATH for executables, eg:
– C:Program Filesnodejs

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Log file for piped output
• Create a suitable directory, eg:
– C:qewdlog
• Create an empty file in it:
– qewd.log

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Dependency on Caché
• When NSSM starts up, it must wait to
make sure Caché has already started
– We need the dependency information
• Control Panel:
– System and Security
• Administrative Tools
– Services

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Dependency on Caché
• In the Services Window that opens up, find
the Service named:
– Caché Controller for Cachexxxx
• Right click on it and select Properties
• At the top you'll see the Service Name
– eg: Cache c- intersystems_cache2015-2
• Copy this to your clipboard

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Start NSSM Installer
• In a Command Prompt window type:
nssm install
• Application Path:
– C:Program Filesnodejsnode.exe
• Startup Directory:
– C:ewd3 (or wherever you start ewd-xpress)
• Arguments:
– ewd-xpress
• Click on Dependencies Tab
– Paste the Caché Service string from clipboard
• Click on I/O tab
– Input: leave blank
– Output: C:qewdlogqewd.log
– Error: C:qewdlogqewd.log
• Give your new service a name:
– QEWD
• Click Install Service

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Start the QEWD Service
• Switch to the Services window
• Click Refresh button
• QEWD should appear in the list of services
• Right-click on it and select Properties
– Service Status will be stopped
– Click Start
• QEWD should now be running
– Test by starting the qewd-monitor application

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Log File
• Look in C:qewdlogqewd.log
• You should see all the console.log activity
being piped there

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Controlling the Service
• Standard Windows Service
• Use the Services panel and find QEWD
– Stop
– Start
– Restart
• If an error occurs that stops the master process,
the QEWD service will automatically restart
• The QEWD service will start automatically when
Windows is re-booted

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NSSM additional features
• Lots more functionality
• Worth exploring documentation at
http://nssm.cc
• To edit your service definition:
– Open Command Prompt window
nssm edit QEWD

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Linux: PM2
• Advanced Node.js Process Manager
– http://pm2.keymetrics.io/
• Install:
– -g option makes pm2 available as a command
cd ~
sudo npm install –g pm2

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Start QEWD as a Service
cd ~/qewd
pm2 start qewd.js
Assuming that qewd.js is the name of your
QEWD startup file.

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Start QEWD as a Service
cd ~/qewd
pm2 start qewd.js
This will be now the PM2 Service name

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Monitor PM2 Services
cd ~/qewd
pm2 status
Displays the status of all your PM2 Services
- online
- stopped

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Stop the QEWD PM2 Service
cd ~/qewd
pm2 stop qewd

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Restart the QEWD PM2 Service
cd ~/qewd
pm2 start qewd
If you've already started QEWD as a service,
and if it appears as stopped in pm2 status,
you don't need to specify the .js file extension

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Restart the QEWD PM2 Service
cd ~/qewd
pm2 restart qewd
To stop and start QEWD again in 1 command

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Logging the output
• PM2 automatically pipes console.log and
error output to log files:
– ~/qewd/.pm2/logs
– You should find:
• ~/.pm2/logs/qewd-out-0.log

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Logging the output
• PM2 automatically pipes console.log and
error output to log files:
– ~/qewd/.pm2/logs
– You should find:
• ~/.pm2/logs/qewd-out-0.log
This number may vary

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Logging the output
• Use the tail command to monitor QEWD
activity in real-time
tail –f ~/.pm2/logs/qewd-out-0.log

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PM2 will auto-restart QEWD
• If an error brings down the QEWD master
process, PM2 will automatically restart it
• Try stopping the master process using
qewd-monitor while tailing the log file
– Watch it stop and immediately restart