Parakeet

A framework for creating Ruby background processes that can be started, stopped, or run in interactive mode for debugging.

Usage

To create a process it's necessary to define a main process that will run. The most minimal form is this:

require 'parakeet'

Parakeet::Instance.new.main do
  loop do
    puts "Main process."

    sleep(1)
  end
end.parse!(ARGV)

It's necessary to have some kind of event-loop running if this process is to be persistent otherwise that block will terminate prematurely.

If this is saved in example.rb then this program can be launched:

ruby example.rb run

In this mode the output from the program is directed to the console. To stop the process use ^C.

It can also be run as a background process if the location of any log files and the PID file used to track status are defined:

require 'parakeet'

Parakeet::Instance.new.options do |program, options|
  options.pid_path = 'example.pid'
  options.log_path = 'example.log'
end.main do
  loop do
    puts "Main process."

    sleep(1)
  end
end.parse!(ARGV)

Then this can be launched as a background process:

ruby example.rb start

Which, once running, will log to that directory instead of STDOUT. The status of this process can be checked:

ruby example.rb status

You can also stop this process any time:

ruby example.rb stop

If the process finishes normally, that is does not return a non-zero exit code, then it's presumed that the shutdown was deliberate and the process is allowed to stop. If not, it's presumed there was an error or exception and after a short delay it's restarted.