pre_forking.rb

include Process

# puts " ROOT: #{pid} of #{ppid}"
# at_exit { puts " EXIT: #{pid} of #{ppid}" }

$running = true
$workers = []
def start_worker
  $workers << fork do
    Signal.trap "INT", "DEFAULT"
    # puts "START: #{pid} of #{ppid}"
    sleep 2 + 5*rand
  end
rescue # meh?
end

Signal.trap("INT") {
  puts "caught INT; killing"
  $running = false
  $workers.each {|pid| kill 'KILL', pid }
  # kill 0 kills, subprocesses AND this process
  # use process groups to get better control
  # kill 'KILL', 0 
  puts "waitall - #{waitall}"
  # sleep 2
  # exit
}

Thread.new do
  loop do
    puts "#{$workers.length}: #{$workers}"
    system "ps ho pid,state,cmd -H -p #{pid},#{$workers.join ','}"
    sleep 0.2
  end
end

begin
  loop do
    # puts "MAIN LOOP (#{$workers})"
    if $running
      start_worker until $workers.length >= 5
    end
    $workers.delete wait
    sleep 1
  end
rescue SystemCallError => e
  puts "caught SystemCallError\ngg wp"
end