Inter-process communication in UNIX

unix_ipc.rb

# IPC 1 - IO.pipe to set up the UNIX-pipe-based interprocess communication

in_r, in_w = IO.pipe; out_r, out_w = IO.pipe; err_r, err_w = IO.pipe

pid = spawn('cat -n', in: in_r, out: out_w, err: err_w)

[in_r, out_w, err_w].each(&:close)

in_w.puts("signal to process")
in_w.close

puts out_r.read
Process.waitpid(pid)

# IPC 2 - UNIX DOMAIN SOCKETS
# SERVER
require "socket"

server = UNIXServer.new('/tmp/simple.sock')

puts "==== Waiting for connection"
socket = server.accept               # block executaion and wait for client connection to the socket

puts "==== Got Request:"
puts socket.readline                 # block execution and wait till the EOL

puts "==== Sending Response"
socket.write("I read you loud and clear, good buddy!")

socket.close

# CLIENT
require "socket"

socket = UNIXSocket.new('/tmp/simple.sock')

puts "==== Sending"
socket.write("Hello server, can you hear me?\n")

puts "==== Getting Response"
puts socket.readline 

socket.close