Ruby script as service

Question

Well, the title say it all. I have a ruby script I want running as a service (one I can start and stop) on my Linux box. I was able to find how to do it on Windows here

Answer 1

Posting my answer after more than a decade Original Poster asked the question.

First, let's create a simple ruby script, which will run an infinite loop:

# mydaemon.rb 
$stdout.reopen('/home/rmishra/mydaemon.log', 'a')
$stdout.sync = true
loop.with_index do |_, i|
  puts i
  sleep(3)
end

You can run the script in the background by appending ampersand:

/home/rmishra$ ruby mydaemon.rb &
[1] *pid*

To start this script automatically and restart it whenever it was stopped or crashed, we will create a service.

# mydaemon.service
[Unit]
Description=Simple supervisor

[Service]
User=username
Group=username
WorkingDirectory=/home/username
Restart=always
ExecStart=/usr/bin/ruby mydaemon.rb

[Install]
WantedBy=multi-user.target

Now, let's copy this service file to systemd directory:

sudo cp mydaemon.service /lib/systemd/system -v

Finally, use the enable command to ensure that the service starts whenever the system boots:

sudo systemctl enable mydaemon.service

The service can be started, stopped or restarted using standard systemd commands:

sudo systemctl status mydaemon
sudo systemctl start mydaemon
sudo systemctl stop mydaemon
sudo systemctl restart mydaemon

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