Class: God::Process

Inherits:
Object
  • Object
show all
Defined in:
lib/god/process.rb

Constant Summary collapse

WRITES_PID = 
[:start, :restart].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Process

Returns a new instance of Process.



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# File 'lib/god/process.rb', line 11

def initialize
  self.log = '/dev/null'

  @pid_file = nil
  @tracking_pid = true
  @user_log = false
  @pid = nil
  @unix_socket = nil
  @log_cmd = nil
  @stop_timeout = God::STOP_TIMEOUT_DEFAULT
  @stop_signal = God::STOP_SIGNAL_DEFAULT
end

Instance Attribute Details

#chroot ⇒ Object

Returns the value of attribute chroot.



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# File 'lib/god/process.rb', line 7

def chroot
  @chroot
end

#dir ⇒ Object

Returns the value of attribute dir.



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# File 'lib/god/process.rb', line 7

def dir
  @dir
end

#env ⇒ Object

Returns the value of attribute env.



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# File 'lib/god/process.rb', line 7

def env
  @env
end

#err_log ⇒ Object

Returns the value of attribute err_log.



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# File 'lib/god/process.rb', line 7

def err_log
  @err_log
end

#err_log_cmd ⇒ Object

Returns the value of attribute err_log_cmd.



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# File 'lib/god/process.rb', line 7

def err_log_cmd
  @err_log_cmd
end

#gid ⇒ Object

Returns the value of attribute gid.



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# File 'lib/god/process.rb', line 7

def gid
  @gid
end

#log ⇒ Object

Returns the value of attribute log.



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# File 'lib/god/process.rb', line 7

def log
  @log
end

#log_cmd ⇒ Object

Returns the value of attribute log_cmd.



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# File 'lib/god/process.rb', line 7

def log_cmd
  @log_cmd
end

#name ⇒ Object

Returns the value of attribute name.



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# File 'lib/god/process.rb', line 7

def name
  @name
end

#restart ⇒ Object

Returns the value of attribute restart.



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# File 'lib/god/process.rb', line 7

def restart
  @restart
end

#start ⇒ Object

Returns the value of attribute start.



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# File 'lib/god/process.rb', line 7

def start
  @start
end

#stop ⇒ Object

Returns the value of attribute stop.



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# File 'lib/god/process.rb', line 7

def stop
  @stop
end

#stop_signal ⇒ Object

Returns the value of attribute stop_signal.



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# File 'lib/god/process.rb', line 7

def stop_signal
  @stop_signal
end

#stop_timeout ⇒ Object

Returns the value of attribute stop_timeout.



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# File 'lib/god/process.rb', line 7

def stop_timeout
  @stop_timeout
end

#uid ⇒ Object

Returns the value of attribute uid.



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# File 'lib/god/process.rb', line 7

def uid
  @uid
end

#umask ⇒ Object

Returns the value of attribute umask.



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# File 'lib/god/process.rb', line 7

def umask
  @umask
end

#unix_socket ⇒ Object

Returns the value of attribute unix_socket.



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# File 'lib/god/process.rb', line 7

def unix_socket
  @unix_socket
end

Instance Method Details

#alive? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/god/process.rb', line 24

def alive?
  if pid
    System::Process.new(pid).exists?
  else
    false
  end
end

#call_action(action) ⇒ Object 



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# File 'lib/god/process.rb', line 210

def call_action(action)
  command = send(action)

  if action == :stop && command.nil?
    pid = self.pid
    command = lambda do
      applog(self, :info, "#{name} stop: default lambda killer")

      ::Process.kill(@stop_signal, pid) rescue nil
      applog(self, :info, "#{name} sent SIG#{@stop_signal}")

      # Poll to see if it's dead
      pid_not_found = false
      @stop_timeout.times do
        if pid
          begin
            ::Process.kill(0, pid)
          rescue Errno::ESRCH
            # It died. Good.
            applog(self, :info, "#{name} process stopped")
            return
          end
        else
          applog(self, :warn, "#{name} pid not found in #{pid_file}") unless pid_not_found
          pid_not_found = true
        end

        sleep 1
      end

      ::Process.kill('KILL', pid) rescue nil
      applog(self, :warn, "#{name} still alive after #{@stop_timeout}s; sent SIGKILL")
    end
  end

  case command
  when String
    if [:start, :restart].include?(action) && @tracking_pid
      # double fork god-daemonized processes
      # we don't want to wait for them to finish
      r, w = IO.pipe
      begin
        opid = fork do
          $stdout.reopen(w)
          r.close
          pid = self.spawn(command)
          puts pid # send pid back to forker
          exit!(0)
        end

        ::Process.waitpid(opid, 0)
        w.close
        pid = r.gets.chomp
      ensure
        # make sure the file descriptors get closed no matter what
        r.close rescue nil
        w.close rescue nil
      end
    else
      # single fork self-daemonizing processes
      # we want to wait for them to finish
      pid = self.spawn(command)
      status = ::Process.waitpid2(pid, 0)
      exit_code = status[1] >> 8

      applog(self, :warn, "#{name} #{action} command exited with non-zero code = #{exit_code}") if exit_code != 0

      ensure_stop if action == :stop
    end

    if @tracking_pid || (@pid_file.nil? && WRITES_PID.include?(action))
      File.write(default_pid_file, pid)

      @tracking_pid = true
      @pid_file = default_pid_file
    end
  when Proc
    # lambda command
    command.call
  else
    raise NotImplementedError
  end
end

#default_pid_file ⇒ Object 



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# File 'lib/god/process.rb', line 206

def default_pid_file
  File.join(God.pid_file_directory, "#{name}.pid")
end

#ensure_stop ⇒ Object

Ensure that a stop command actually stops the process. Force kill if necessary.

Returns nothing



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# File 'lib/god/process.rb', line 345

def ensure_stop
  applog(self, :warn, "#{name} ensuring stop...")

  unless pid
    applog(self, :warn, "#{name} stop called but pid is uknown")
    return
  end

  # Poll to see if it's dead
  @stop_timeout.times do
    begin
      ::Process.kill(0, pid)
    rescue Errno::ESRCH
      # It died. Good.
      return
    end

    sleep 1
  end

  # last resort
  ::Process.kill('KILL', pid) rescue nil
  applog(self, :warn, "#{name} still alive after #{@stop_timeout}s; sent SIGKILL")
end

#file_writable?(file) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/god/process.rb', line 32

def file_writable?(file)
  pid = fork do
    begin
      if uid
        user_method = uid.is_a?(Integer) ? :getpwuid : :getpwnam
        uid_num = Etc.send(user_method, uid).uid
        gid_num = Etc.send(user_method, uid).gid
      end
      if gid
        group_method = gid.is_a?(Integer) ? :getgrgid : :getgrnam
        gid_num = Etc.send(group_method, gid).gid
      end

      ::Dir.chroot(chroot) if chroot
      ::Process.groups = [gid_num] if gid_num
      ::Process.initgroups(uid, gid_num) if uid && gid_num
      ::Process::Sys.setgid(gid_num) if gid_num
      ::Process::Sys.setuid(uid_num) if uid
    rescue ArgumentError, Errno::EPERM, Errno::ENOENT
      exit(1)
    end

    File.writable?(file_in_chroot(file)) ? exit!(0) : exit!(1)
  end

  _wpid, status = ::Process.waitpid2(pid)
  status.exitstatus == 0
end

#pid ⇒ Object

Fetch the PID from pid_file. If the pid_file does not exist, then use the PID from the last time it was read. If it has never been read, then return nil.

Returns Integer(pid) or nil



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# File 'lib/god/process.rb', line 173

def pid
  contents = File.read(pid_file).strip rescue ''
  real_pid = /^\d+$/.match?(contents) ? contents.to_i : nil

  if real_pid
    @pid = real_pid
    real_pid
  else
    @pid
  end
end

#pid_file ⇒ Object 



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# File 'lib/god/process.rb', line 164

def pid_file
  @pid_file ||= default_pid_file
end

#pid_file=(value) ⇒ Object

DON’T USE THIS INTERNALLY. Use the instance variable. – Kev No really, trust me. Use the instance variable.



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# File 'lib/god/process.rb', line 153

def pid_file=(value)
  # if value is nil, do the right thing
  @tracking_pid = if value
                    false
                  else
                    true
                  end

  @pid_file = value
end

#restart! ⇒ Object 



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# File 'lib/god/process.rb', line 202

def restart!
  call_action(:restart)
end

#signal(sig) ⇒ Object

Send the given signal to this process.

Returns nothing



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# File 'lib/god/process.rb', line 188

def signal(sig)
  sig = sig.to_i if sig.to_i != 0
  applog(self, :info, "#{name} sending signal '#{sig}' to pid #{pid}")
  ::Process.kill(sig, pid) rescue nil
end

#spawn(command) ⇒ Object

Fork/exec the given command, returns immediately

+command+ is the String containing the shell command

Returns nothing



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# File 'lib/god/process.rb', line 298

def spawn(command)
  fork do
    File.umask umask if umask
    uid_num = Etc.getpwnam(uid).uid if uid
    gid_num = Etc.getgrnam(gid).gid if gid
    gid_num = Etc.getpwnam(uid).gid if gid.nil? && uid

    ::Dir.chroot(chroot) if chroot
    ::Process.setsid
    ::Process.groups = [gid_num] if gid_num
    ::Process.initgroups(uid, gid_num) if uid && gid_num
    ::Process::Sys.setgid(gid_num) if gid_num
    ::Process::Sys.setuid(uid_num) if uid
    self.dir ||= '/'
    Dir.chdir self.dir
    $0 = command
    $stdin.reopen '/dev/null'
    if log_cmd
      $stdout.reopen IO.popen(log_cmd, 'a')
    else
      $stdout.reopen file_in_chroot(log), 'a'
    end
    if err_log_cmd
      $stderr.reopen IO.popen(err_log_cmd, 'a')
    elsif err_log && (log_cmd || err_log != log)
      $stderr.reopen file_in_chroot(err_log), 'a'
    else
      $stderr.reopen $stdout
    end

    # close any other file descriptors
    3.upto(256) { |fd| IO.new(fd).close rescue nil }

    if env.is_a?(Hash)
      env.each do |(key, value)|
        ENV[key] = value.to_s
      end
    end

    exec command unless command.empty?
  end
end

#start! ⇒ Object 



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# File 'lib/god/process.rb', line 194

def start!
  call_action(:start)
end

#stop! ⇒ Object 



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# File 'lib/god/process.rb', line 198

def stop!
  call_action(:stop)
end

#valid? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/god/process.rb', line 61

def valid?
  # determine if we're tracking pid or not
  pid_file

  valid = true

  # a start command must be specified
  if start.nil?
    valid = false
    applog(self, :error, 'No start command was specified')
  end

  # uid must exist if specified
  if uid
    begin
      Etc.getpwnam(uid)
    rescue ArgumentError
      valid = false
      applog(self, :error, "UID for '#{uid}' does not exist")
    end
  end

  # gid must exist if specified
  if gid
    begin
      Etc.getgrnam(gid)
    rescue ArgumentError
      valid = false
      applog(self, :error, "GID for '#{gid}' does not exist")
    end
  end

  # dir must exist and be a directory if specified
  if dir
    if !File.exist?(dir)
      valid = false
      applog(self, :error, "Specified directory '#{dir}' does not exist")
    elsif !File.directory?(dir)
      valid = false
      applog(self, :error, "Specified directory '#{dir}' is not a directory")
    end
  end

  # pid dir must exist if specified
  if !@tracking_pid && !File.exist?(File.dirname(pid_file))
    valid = false
    applog(self, :error, "PID file directory '#{File.dirname(pid_file)}' does not exist")
  end

  # pid dir must be writable if specified
  if !@tracking_pid && File.exist?(File.dirname(pid_file)) && !file_writable?(File.dirname(pid_file))
    valid = false
    applog(self, :error, "PID file directory '#{File.dirname(pid_file)}' is not writable by #{uid || Etc.getlogin}")
  end

  # log dir must exist
  unless File.exist?(File.dirname(log))
    valid = false
    applog(self, :error, "Log directory '#{File.dirname(log)}' does not exist")
  end

  # log file or dir must be writable
  if File.exist?(log)
    unless file_writable?(log)
      valid = false
      applog(self, :error, "Log file '#{log}' exists but is not writable by #{uid || Etc.getlogin}")
    end
  else
    unless file_writable?(File.dirname(log))
      valid = false
      applog(self, :error, "Log directory '#{File.dirname(log)}' is not writable by #{uid || Etc.getlogin}")
    end
  end

  # chroot directory must exist and have /dev/null in it
  if chroot
    unless File.directory?(chroot)
      valid = false
      applog(self, :error, "CHROOT directory '#{chroot}' does not exist")
    end

    unless File.exist?(File.join(chroot, '/dev/null'))
      valid = false
      applog(self, :error, "CHROOT directory '#{chroot}' does not contain '/dev/null'")
    end
  end

  valid
end