Unicorn::Launcher

Public Class Methods

daemonize!(options = nil) 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 = nil)
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:       if options
29:         # grandparent - reads pipe, exits when master is ready
30:         #  \_ parent  - exits immediately ASAP
31:         #      \_ unicorn master - writes to pipe when ready
32: 
33:         rd, wr = IO.pipe
34:         grandparent = $$
35:         if fork
36:           wr.close # grandparent does not write
37:         else
38:           rd.close # unicorn master does not read
39:           Process.setsid
40:           exit if fork # parent dies now
41:         end
42: 
43:         if grandparent == $$
44:           # this will block until HttpServer#join runs (or it dies)
45:           master_pid = (rd.readpartial(16) rescue nil).to_i
46:           unless master_pid > 1
47:             warn "master failed to start, check stderr log for details"
48:             exit!(1)
49:           end
50:           exit 0
51:         else # unicorn master process
52:           options[:ready_pipe] = wr
53:         end
54:       else # backwards compat
55:         exit if fork
56:         Process.setsid
57:         exit if fork
58:       end
59:       # $stderr/$stderr can/will be redirected separately in the Unicorn config
60:       Unicorn::Configurator::DEFAULTS[:stderr_path] = "/dev/null"
61:       Unicorn::Configurator::DEFAULTS[:stdout_path] = "/dev/null"
62:     end
63:   end

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Unicorn::Launcher

Public Class Methods