zmq_pub_sub_no_topic_hello_world.rb

require 'ffi-rzmq'
require 'timeout'

socket_path = 'tcp://127.0.0.1:5050'
# socket_path = 'ipc://zmq_pub_sub.ipc'

ctx = ZMQ::Context.create

# Subscriber
sub_thread = Thread.new do
  sub_sock = ctx.socket ZMQ::SUB
  sub_sock.setsockopt ZMQ::SUBSCRIBE, '' #Subscribe to everything.
  sub_sock.bind socket_path

  message = ''
  Timeout.timeout 5 do
    sub_sock.recv_string message
  end

  puts "SUB Message: #{message}"
  sub_sock.close
end

# Publisher
pub_sock = ctx.socket ZMQ::PUB
pub_sock.connect socket_path

sleep 0.1 # Let the subscriber spin up.

pub_sock.send_string 'Hello'
pub_sock.close

# Cleanup
sub_thread.join
ctx.terminate