io_pipe

io_pipe.rb

require 'json'

# r, w = IO.pipe
# w << 'secret'
# w << ' message'
# w.close_write
# r.read #=> "secret message"

# if fork
#   wr.close
#   puts "Parent got: <#{rd.read}>"
#   rd.close
#   Process.wait
# else
#   rd.close
#   puts "Sending message to parent"
#   wr << "Hi Dad" << " Bye Mom"
#   wr.close
# end

# the pipe
rd, wr = IO.pipe

# creates a new process
# this should happen in the worker
process_pid = fork do
  Signal.trap("HUP") do 
    puts "Ouch!"; exit 
  end
  
  for i in (1..12)
    sleep 1
    wr << "{no_of_messages:#{i}}\n" unless i == 5
    if i == 5
      wr << "{end:true}\n"      
    end
  end
end

# gets messages
# this should be in the manager
until rd.closed? do
  buf = rd.readpartial(4096)
  puts buf
  if buf == "{end:true}\n" then
    rd.close_read
    Process.kill("HUP", process_pid)  
  end
end

# Process.wait
# wr.close_write
# puts rd.read
# puts rd.flush.inspect

# aux = rd.readpartial(4096)

# puts 'before'
# rd.each_line do |l|
#   puts l
#   puts rd.inspect
#   
#   Process.kill("HUP", process_pid) if l == "{end:true}\n"
#   break if rd.closed?
# end
# puts 'after'

# res = aux.split(',') 
# puts res.inspect
# 
# res.each |r|
#   puts JSON.parse(r).inspect  
# end