How to find the local port a rails instance is running on?

Question

So I would like my Rails app instances to register themselves on a \"I\'m up\" kind of thing I\'m playing with, and I\'d like it to be able to mention what local port it\'s

Answer 1

For Rails 5.1 development server.

if Rack::Server.new.options[:Port] != 9292 # rals s -p PORT
  local_port = Rack::Server.new.options[:Port]
else
  local_port = (ENV['PORT'] || '3000').to_i # ENV['PORT'] for foreman
end