poller_remove.rb

require 'thread'
require 'ffi-rzmq'

def broker
  ctx = ZMQ::Context.new
  socket = ctx.socket(ZMQ::ROUTER)
  socket.setsockopt ZMQ::LINGER, 0
  socket.bind 'tcp://*:55555'

  poller = ZMQ::Poller.new
  poller.register socket, ZMQ::POLLIN

  loop do
    items = poller.poll :blocking
    if items > 0
      message = []
      @socket.recv_strings message
      @socket.send_strings message
    end
  end
end

def worker
  ctx = ZMQ::Context.new
  poller = ZMQ::Poller.new
  socket = get_socket ctx

  poller.register socket, ZMQ::POLLIN

  loop do
    puts "sockets in poller: #{poller.size}"
    items = poller.poll 1000
    if items > 0
    else
      # What should I do here to deregister? Can't find documentation about this
      poller.deregister socket, ZMQ::POLLIN
      # poller.delete socket
      socket = get_socket ctx
      poller.register socket, ZMQ::POLLIN
    end
  end

end

def get_socket ctx
  socket = ctx.socket ZMQ::DEALER
  socket.setsockopt ZMQ::LINGER, 0
  socket.connect 'tcp://localhost:55555'
  socket
end

threads = []
threads << Thread.start do
  begin
    broker
  rescue Exception => e
    puts e
    e.backtrace.each { |line| puts line }
  end
end

worker

# Expected output:
# sockets in poller: 1
# sockets in poller: 1
# sockets in poller: 1
# sockets in poller: 1
# sockets in poller: 1
# sockets in poller: 1
# sockets in poller: 1
#
# Real output:
# sockets in poller: 1
# sockets in poller: 2
# sockets in poller: 3
# sockets in poller: 4
# sockets in poller: 5
# sockets in poller: 6
# sockets in poller: 7