Unicorn::Launcher

Public Class Methods

daemonize!(options) click to toggle source

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.

    # File lib/unicorn/launcher.rb, line 22
22:   def self.daemonize!(options)
23:     $stdin.reopen("/dev/null")
24: 
25:     # We only start a new process group if we're not being reexecuted
26:     # and inheriting file descriptors from our parent
27:     unless ENV['UNICORN_FD']
28:       # grandparent - reads pipe, exits when master is ready
29:       #  \_ parent  - exits immediately ASAP
30:       #      \_ unicorn master - writes to pipe when ready
31: 
32:       rd, wr = IO.pipe
33:       grandparent = $$
34:       if fork
35:         wr.close # grandparent does not write
36:       else
37:         rd.close # unicorn master does not read
38:         Process.setsid
39:         exit if fork # parent dies now
40:       end
41: 
42:       if grandparent == $$
43:         # this will block until HttpServer#join runs (or it dies)
44:         master_pid = (rd.readpartial(16) rescue nil).to_i
45:         unless master_pid > 1
46:           warn "master failed to start, check stderr log for details"
47:           exit!(1)
48:         end
49:         exit 0
50:       else # unicorn master process
51:         options[:ready_pipe] = wr
52:       end
53:     end
54:     # $stderr/$stderr can/will be redirected separately in the Unicorn config
55:     Unicorn::Configurator::DEFAULTS[:stderr_path] ||= "/dev/null"
56:     Unicorn::Configurator::DEFAULTS[:stdout_path] ||= "/dev/null"
57:     Unicorn::Configurator::RACKUP[:daemonized] = true
58:   end

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Unicorn::Launcher

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