Module: Revenant::Manager

Extended by:
Manager
Included in:
Manager
Defined in:
lib/revenant/manager.rb

Instance Method Summary collapse

Instance Method Details

#close_open_files ⇒ Object

Close anything that is not one of the three standard IO streams.



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# File 'lib/revenant/manager.rb', line 28

def close_open_files
  ObjectSpace.each_object(IO) do |io|
    next if [STDIN, STDOUT, STDERR].include?(io)
    begin
      io.close unless io.closed?
    rescue ::Exception
    end
  end
end

#daemonize(name, log_file = nil) ⇒ Object 



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# File 'lib/revenant/manager.rb', line 5

def daemonize(name, log_file = nil)
  # Firstly, get rid of the filthy dirty original process.
  exit!(0) if fork

  # Now that we aren't attached to a terminal, we can become
  # a session leader.
  begin
    Process.setsid
  rescue Errno::EPERM
    raise SystemCallError, "setsid failed. terminal failed to detach?"
  end
  trap 'SIGHUP', 'IGNORE' # don't do anything crazy when this process exits

  # Finally, time to create a daemonized process
  exit!(0) if fork

  $0 = name.to_s # set the process name
  close_open_files
  redirect_io_to(log_file)
  srand # re-seed the PRNG with our 'final' pid
end

#redirect_io_to(log_file) ⇒ Object

Redirects STDIN, STDOUT, and STDERR to the specified log_file or to /dev/null if none is given.



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# File 'lib/revenant/manager.rb', line 40

def redirect_io_to(log_file)
  log_file ||= "/dev/null"
  reopen_io STDIN, "/dev/null"
  reopen_io STDOUT, log_file, "a"
  reopen_io STDERR, STDOUT
  STDERR.sync = STDOUT.sync = true
end

#reopen_io(io, path, mode = nil) ⇒ Object

Attempts to reopen an IO object.



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# File 'lib/revenant/manager.rb', line 49

def reopen_io(io, path, mode = nil)
  begin
    if mode
      io.reopen(path, mode)
    else
      io.reopen(path)
    end
    io.binmode
  rescue ::Exception
  end
end