Class: AlchemyServer::ProcessHelper

Inherits:
Object
  • Object
show all
Defined in:
lib/alchemy/runner.rb

Instance Method Summary collapse

Constructor Details

#initialize(log_file = nil, pid_file = nil, user = nil, group = nil) ⇒ ProcessHelper

Returns a new instance of ProcessHelper.



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# File 'lib/alchemy/runner.rb', line 148

def initialize(log_file = nil, pid_file = nil, user = nil, group = nil)
  @log_file = log_file
  @pid_file = pid_file
  @user = user
  @group = group
end

Instance Method Details

#close_io_handles ⇒ Object 



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# File 'lib/alchemy/runner.rb', line 192

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

#daemonize ⇒ Object 



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# File 'lib/alchemy/runner.rb', line 166

def daemonize
  sess_id = detach_from_terminal
  exit if pid = safefork

  Dir.chdir("/")
  File.umask 0000

  close_io_handles
  redirect_io

  return sess_id
end

#detach_from_terminal ⇒ Object 



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# File 'lib/alchemy/runner.rb', line 179

def detach_from_terminal
  srand
  safefork and exit

  unless sess_id = Process.setsid
    raise "Couldn't detache from controlling terminal."
  end

  trap 'SIGHUP', 'IGNORE'

  sess_id
end

#redirect_io ⇒ Object 



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# File 'lib/alchemy/runner.rb', line 203

def redirect_io
  begin; STDIN.reopen('/dev/null'); rescue Exception; end

  if @log_file
    begin
      STDOUT.reopen(@log_file, "a")
      STDOUT.sync = true
    rescue Exception
      begin; STDOUT.reopen('/dev/null'); rescue Exception; end 
    end
  else
    begin; STDOUT.reopen('/dev/null'); rescue Exception; end
  end

  begin; STDERR.reopen(STDOUT); rescue Exception; end
  STDERR.sync = true
end

#remove_pid_file ⇒ Object 



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# File 'lib/alchemy/runner.rb', line 234

def remove_pid_file
  return unless @pid_file
  File.unlink(@pid_file) if File.exists?(@pid_file)
end

#rescue_exception ⇒ Object 



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# File 'lib/alchemy/runner.rb', line 221

def rescue_exception
  begin
    yield
  rescue Exception
  end
end

#running? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/alchemy/runner.rb', line 239

def running?
  return false unless @pid_file

  pid = File.read(@pid_file).chomp.to_i rescue nil
  pid = nil if pid == 0
  return false unless pid

  begin
    Process.kill(0, pid)
    return pid
  rescue Errno::ESRCH
    return nil
  rescue Errno::EPERM
    return pid
  end
end

#safefork ⇒ Object 



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# File 'lib/alchemy/runner.rb', line 155

def safefork
  begin
    if pid = fork
      return pid
    end
  rescue Errno::EWOULDBLOCK
    sleep 5
    retry
  end
end

#write_pid_file ⇒ Object 



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# File 'lib/alchemy/runner.rb', line 228

def write_pid_file
  return unless @pid_file
  File.open(@pid_file, "w") { |f| f.write(Process.pid) }
  File.chmod(0644, @pid_file)
end