How to start a rails task as a service

Question

I have a TCP server written in the rails application as a rails task. However it can be started from as:

  rails socketing:start  

and the process will start executing if wanted it to be a task that keep on running in the beckground them change it as:

nohup rails socketing:start &

and will be keep on working in backgroup as the tcp server has multi threading implemented into it if there is an error that will stop only 1 thread.

Now I would like this process to be started by the service at the boottime of the ubuntu server for that created a service and enabled it. But the code break can you please suggest a way out My service is written as:

[Unit]
Description = TCP at 51234
After = network.target

[Service]
Environment="HOME=/home/vidur"
ExecStart = /home/vidur/rails_app/tukaweb/custom_script.sh

[Install]
WantedBy = multi-user.target

My custom_script.sh as:

#!/bin/bash

 cd /home/vidur/rails_app/project_dir
/home/vidur/.rbenv/shims/bundler exec rails socketing:start

Start the service as:

sudo systemctl start socketing.service

It give o/p as:

Jun 10 17:45:31 Vidur-PC systemd[1]: Started TCP at 51234.
Jun 10 17:45:31 Vidur-PC systemd[1]: socketing.service: Succeeded.

But did not start the rails task or even recognise rails environment: I have rails task as:

  task start: :environment do
    require 'socket'
    puts "Started TCP Server at PORT 53492"
    server = TCPServer.new 51324 # Server bound to port 51234
   loop do
      Thread.start(server.accept) do |client|
      client.close
    end
   end

    p "result = #{result}"
    p 'Bye'
  end

This code gives following error:

Jun 10 19:16:40 Vidur-PC systemd[1]: Started TCP at 53492.
Jun 10 19:16:43 Vidur-PC custom_script.sh[60012]: rake aborted!
Jun 10 19:16:43 Vidur-PC custom_script.sh[60012]: ArgumentError: couldn't find login name -- expanding `~'
Jun 10 19:16:43 Vidur-PC custom_script.sh[60012]: /home/vidur/rails_app/tukaweb/config/application.rb:8:in `<top (required)>'
Jun 10 19:16:43 Vidur-PC custom_script.sh[60012]: /home/vidur/rails_app/tukaweb/Rakefile:4:in `require_relative'
Jun 10 19:16:43 Vidur-PC custom_script.sh[60012]: /home/vidur/rails_app/tukaweb/Rakefile:4:in `<top (required)>'
Jun 10 19:16:43 Vidur-PC custom_script.sh[60012]: /home/vidur/.rbenv/versions/2.7.2/bin/bundler:23:in `load'
Jun 10 19:16:43 Vidur-PC custom_script.sh[60012]: /home/vidur/.rbenv/versions/2.7.2/bin/bundler:23:in `<main>'
Jun 10 19:16:43 Vidur-PC custom_script.sh[60012]: (See full trace by running task with --trace)
Jun 10 19:16:44 Vidur-PC systemd[1]: socketing.service: Main process exited, code=exited, status=1/FAILURE
Jun 10 19:16:44 Vidur-PC systemd[1]: socketing.service: Failed with result 'exit-code'.

updated application.rb file:

require_relative 'boot'

require 'rails/all'

# Require the gems listed in Gemfile, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(*Rails.groups)

module TukaWeb
  class Application < Rails::Application
    # Initialize configuration defaults for originally generated Rails version.
    config.load_defaults 5.1
    if Rails.env.development?
        config.active_job.queue_adapter  = :async
      else
        config.active_job.queue_adapter  = :sidekiq
    end

    config.generators.javascript_engine = :js

    config.action_dispatch.default_headers = {
        'Access-Control-Allow-Origin' => 'https://tukadata.tukatech.com',
        'Access-Control-Request-Method' => %w{GET POST OPTIONS}.join(",")
    }
    # Settings in config/environments/* take precedence over those specified here.
    # Application configuration should go into files in config/initializers
    # -- all .rb files in that directory are automatically loaded.
  end
end

It stated the tcp process rake task but for the root user only.

DB Error left:

`connect': Access denied for user 'root'@'localhost'

but if run the process normal then it run.

Answer 1

file would be inside folder: /etc/systemd/system:

[Unit]
Description=TCP Service
After=network.target

[Service]
#Environment="HOME=/home/vidur"
ExecStart=/home/vidur/rails_apps/jquery_app/custom_script.sh
Restart=always

[Install]
WantedBy = multi-user.target

Also use following commands as required:

sudo systemctl enable tcpstart
sudo ufw allow 3005
sudo service tcpstart start
sudo service tcpstart status