Class: God::Process

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

Constant Summary

WRITES_PID =
[:start, :restart]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initializeProcess



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# File 'lib/god/process.rb', line 9

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

#chrootObject

Returns the value of attribute chroot



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# File 'lib/god/process.rb', line 5

def chroot
  @chroot
end

#dirObject

Returns the value of attribute dir



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# File 'lib/god/process.rb', line 5

def dir
  @dir
end

#envObject

Returns the value of attribute env



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# File 'lib/god/process.rb', line 5

def env
  @env
end

#err_logObject

Returns the value of attribute err_log



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# File 'lib/god/process.rb', line 5

def err_log
  @err_log
end

#err_log_cmdObject

Returns the value of attribute err_log_cmd



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# File 'lib/god/process.rb', line 5

def err_log_cmd
  @err_log_cmd
end

#gidObject

Returns the value of attribute gid



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# File 'lib/god/process.rb', line 5

def gid
  @gid
end

#logObject

Returns the value of attribute log



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# File 'lib/god/process.rb', line 5

def log
  @log
end

#log_cmdObject

Returns the value of attribute log_cmd



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# File 'lib/god/process.rb', line 5

def log_cmd
  @log_cmd
end

#nameObject

Returns the value of attribute name



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# File 'lib/god/process.rb', line 5

def name
  @name
end

#restartObject

Returns the value of attribute restart



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# File 'lib/god/process.rb', line 5

def restart
  @restart
end

#startObject

Returns the value of attribute start



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# File 'lib/god/process.rb', line 5

def start
  @start
end

#stopObject

Returns the value of attribute stop



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# File 'lib/god/process.rb', line 5

def stop
  @stop
end

#stop_signalObject

Returns the value of attribute stop_signal



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# File 'lib/god/process.rb', line 5

def stop_signal
  @stop_signal
end

#stop_timeoutObject

Returns the value of attribute stop_timeout



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# File 'lib/god/process.rb', line 5

def stop_timeout
  @stop_timeout
end

#uidObject

Returns the value of attribute uid



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# File 'lib/god/process.rb', line 5

def uid
  @uid
end

#umaskObject

Returns the value of attribute umask



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# File 'lib/god/process.rb', line 5

def umask
  @umask
end

#unix_socketObject

Returns the value of attribute unix_socket



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# File 'lib/god/process.rb', line 5

def unix_socket
  @unix_socket
end

Instance Method Details

#alive?Boolean



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# File 'lib/god/process.rb', line 22

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

#call_action(action) ⇒ Object



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

def call_action(action)
  command = send(action)

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

      ::Process.kill(@stop_signal, pid) rescue nil
      applog(self, :info, "#{self.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, "#{self.name} process stopped")
            return
          end
        else
          applog(self, :warn, "#{self.name} pid not found in #{self.pid_file}") unless pid_not_found
          pid_not_found = true
        end

        sleep 1
      end

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

  if command.kind_of?(String)
    pid = nil

    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.to_s # 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

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

      ensure_stop if action == :stop
    end

    if @tracking_pid or (@pid_file.nil? and WRITES_PID.include?(action))
      File.open(default_pid_file, 'w') do |f|
        f.write pid
      end

      @tracking_pid = true
      @pid_file = default_pid_file
    end
  elsif command.kind_of?(Proc)
    # lambda command
    command.call
  else
    raise NotImplementedError
  end
end

#default_pid_fileObject



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

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

#ensure_stopObject

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 343

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

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

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

    sleep 1
  end

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

#file_writable?(file) ⇒ Boolean



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# File 'lib/god/process.rb', line 30

def file_writable?(file)
  pid = fork do
    begin
      uid_num = Etc.getpwnam(self.uid).uid if self.uid
      gid_num = Etc.getgrnam(self.gid).gid if self.gid
      gid_num = Etc.getpwnam(self.uid).gid if self.gid.nil? && self.uid

      ::Dir.chroot(self.chroot) if self.chroot
      ::Process.groups = [gid_num] if gid_num
      ::Process.initgroups(self.uid, gid_num) if self.uid && gid_num
      ::Process::Sys.setgid(gid_num) if gid_num
      ::Process::Sys.setuid(uid_num) if self.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 ? true : false
end

#pidObject

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 165

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

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

#pid_fileObject



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# File 'lib/god/process.rb', line 156

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 145

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

  @pid_file = value
end

#restart!Object



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

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 180

def signal(sig)
  sig = sig.to_i if sig.to_i != 0
  applog(self, :info, "#{self.name} sending signal '#{sig}' to pid #{self.pid}")
  ::Process.kill(sig, self.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 296

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

    ::Dir.chroot(self.chroot) if self.chroot
    ::Process.setsid
    ::Process.groups = [gid_num] if gid_num
    ::Process.initgroups(self.uid, gid_num) if self.uid && gid_num
    ::Process::Sys.setgid(gid_num) if gid_num
    ::Process::Sys.setuid(uid_num) if self.uid
    self.dir ||= '/'
    Dir.chdir self.dir
    $0 = command
    STDIN.reopen "/dev/null"
    if self.log_cmd
      STDOUT.reopen IO.popen(self.log_cmd, "a")
    else
      STDOUT.reopen file_in_chroot(self.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 self.env && self.env.is_a?(Hash)
      self.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 186

def start!
  call_action(:start)
end

#stop!Object



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# File 'lib/god/process.rb', line 190

def stop!
  call_action(:stop)
end

#valid?Boolean



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# File 'lib/god/process.rb', line 53

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

  valid = true

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

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

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

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

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

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

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

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

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

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

  valid
end