Is there a way to pass a param from one completely separate ruby program to another on the same network and/or machine?

Question

I am replacing existing programs with ruby little by little so as not break any existing functionality. The need for separate ruby programs may/ has arrived but I still need them to be able to interact with each other.

Geoff Parsons · Answer

You've got a few options for this depending on your setup.
If both programs are running on the same machine and one will be executing the other you could simply pass command line parameters to the ruby script using the system method (http://www.ruby-doc.org/core-2.2.0/Kernel.html#method-i-system) and ARGV (http://ruby-doc.org/core-2.1.5/ARGF.html#method-i-argv). This can get quite fragile though so you may want to consider some other options.
You could also use low level sockets via the Socket (http://www.ruby-doc.org/stdlib-2.1.5/libdoc/socket/rdoc/Socket.html) class in the standard library.
```server.rb
require 'socket'
server = TCPServer.new 2000 # Server bound to port 2000
loop do
  client = server.accept    # Wait for a client to connect
  client.puts "Hello !"
  client.puts "Time is #{Time.now}"
  client.close
end
```
```client.rb
require 'socket'
s = TCPSocket.new 'localhost', 2000
while line = s.gets # Read lines from socket
  puts line         # and print them
end
s.close             # close socket when done
```
There are many other options including web services, messaging queues (e.g. resque or sidekiq), etc.

Welcome to the Treehouse Community

Looking to learn something new?

Nick Hennen

Nick Hennen

Is there a way to pass a param from one completely separate ruby program to another on the same network and/or machine?

1 Answer

Geoff Parsons

Geoff Parsons