respawn_unicorn_children.rb

#!/usr/bin/env ruby
#
# 2010/12/21 Kazuki Ohta <[email protected]>
# Respawn unicorn child processes.
#

rails_root =  ENV["RAILS_HOME"]

# master
unicorn_master_pid_file = File.expand_path("tmp/pids/unicorn.pid", rails_root)
unicorn_master_pid = File.read(unicorn_master_pid_file).to_i

# children
ps_output = `ps w --ppid #{unicorn_master_pid}`
ps_output_lines = ps_output.split("\n")

children = []
ps_output_lines.each do |line|
  chunks = line.strip.split(/\s+/, 5)
  pid, pcmd = chunks[0], chunks[4]
  next if pid !~ /\A\d+\z/ or pcmd !~ /worker/
  children << pid.to_i
end

children.each { |pid|
  Process.kill :QUIT, pid
}