Module: Unicorn::Launcher

Defined in:
lib/unicorn/launcher.rb

Class Method Summary collapse

Class Method Details

.daemonize!(options) ⇒ Object

We don’t do a lot of standard daemonization stuff:

* umask is whatever was set by the parent process at startup
  and can be set in config.ru and config_file, so making it
  0000 and potentially exposing sensitive log data can be bad
  policy.
* don't bother to chdir("/") here since unicorn is designed to
  run inside APP_ROOT.  Unicorn will also re-chdir() to
  the directory it was started in when being re-executed
  to pickup code changes if the original deployment directory
  is a symlink or otherwise got replaced.



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# File 'lib/unicorn/launcher.rb', line 22

def self.daemonize!(options)
  cfg = Unicorn::Configurator
  $stdin.reopen("/dev/null")

  # We only start a new process group if we're not being reexecuted
  # and inheriting file descriptors from our parent
  unless ENV['UNICORN_FD']
    # grandparent - reads pipe, exits when master is ready
    #  \_ parent  - exits immediately ASAP
    #      \_ unicorn master - writes to pipe when ready

    rd, wr = IO.pipe
    grandparent = $$
    if fork
      wr.close # grandparent does not write
    else
      rd.close # unicorn master does not read
      Process.setsid
      exit if fork # parent dies now
    end

    if grandparent == $$
      # this will block until HttpServer#join runs (or it dies)
      master_pid = (rd.readpartial(16) rescue nil).to_i
      unless master_pid > 1
        warn "master failed to start, check stderr log for details"
        exit!(1)
      end
      exit 0
    else # unicorn master process
      options[:ready_pipe] = wr
    end
  end
  # $stderr/$stderr can/will be redirected separately in the Unicorn config
  cfg::DEFAULTS[:stderr_path] ||= "/dev/null"
  cfg::DEFAULTS[:stdout_path] ||= "/dev/null"
  cfg::RACKUP[:daemonized] = true
end