Class: Procodile::Instance

Inherits:
Object
  • Object
show all
Defined in:
lib/procodile/instance.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(supervisor, process, id) ⇒ Instance

Returns a new instance of Instance.



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# File 'lib/procodile/instance.rb', line 12

def initialize(supervisor, process, id)
  @supervisor = supervisor
  @process = process
  @id = id
  @respawns = 0
  @started_at = nil
end

Instance Attribute Details

#id ⇒ Object (readonly)

Returns the value of attribute id.



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# File 'lib/procodile/instance.rb', line 7

def id
  @id
end

#pid ⇒ Object

Returns the value of attribute pid.



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# File 'lib/procodile/instance.rb', line 6

def pid
  @pid
end

#port ⇒ Object (readonly)

Returns the value of attribute port.



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# File 'lib/procodile/instance.rb', line 10

def port
  @port
end

#process ⇒ Object

Returns the value of attribute process.



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# File 'lib/procodile/instance.rb', line 8

def process
  @process
end

#tag ⇒ Object (readonly)

Returns the value of attribute tag.



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# File 'lib/procodile/instance.rb', line 9

def tag
  @tag
end

Instance Method Details

#add_respawn ⇒ Object

Increment the counter of respawns for this process



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# File 'lib/procodile/instance.rb', line 285

def add_respawn
  if @last_respawn && @last_respawn < (Time.now - @process.respawn_window)
    @respawns = 1
  else
    @last_respawn = Time.now
    @respawns += 1
  end
end

#allocate_port ⇒ Object

Find a port number for this instance to listen on. We just check that nothing is already listening on it. The process is expected to take it straight away if it wants it.



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# File 'lib/procodile/instance.rb', line 315

def allocate_port
  until @port
    possible_port = rand(10000) + 20000
    begin
      server = TCPServer.new('127.0.0.1', possible_port)
      server.close
      return @port = possible_port
    rescue
      # Nah.
    end
  end
end

#can_respawn? ⇒ Boolean

Can this process be respawned if needed?

Returns:

  • (Boolean) 


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# File 'lib/procodile/instance.rb', line 267

def can_respawn?
  !stopping? && (respawns + 1) <= @process.max_respawns
end

#check(options = {}) ⇒ Object

Check the status of this process and handle as appropriate.



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# File 'lib/procodile/instance.rb', line 234

def check(options = {})
  return if failed?

  if self.running?
    # Everything is OK. The process is running.
    true
  else
    # If the process isn't running any more, update the PID in our memory from
    # the file in case the process has changed itself.
    return check if update_pid

    if @supervisor.allow_respawning?
      if can_respawn?
        Procodile.log(@process.log_color, description, "Process has stopped. Respawning...")
        start
        add_respawn
      elsif respawns >= @process.max_respawns
        Procodile.log(@process.log_color, description, "\e[41;37mWarning:\e[0m\e[31m this process has been respawned #{respawns} times and keeps dying.\e[0m")
        Procodile.log(@process.log_color, description, "It will not be respawned automatically any longer and will no longer be managed.".color(31))
        @failed = Time.now
        tidy
      end
    else
      Procodile.log(@process.log_color, description, "Process has stopped. Respawning not available.")
      @failed = Time.now
      tidy
    end
  end
end

#description ⇒ Object

Return a description for this instance



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# File 'lib/procodile/instance.rb', line 23

def description
  "#{@process.name}.#{@id}"
end

#environment_variables ⇒ Object

Return an array of environment variables that should be set



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# File 'lib/procodile/instance.rb', line 47

def environment_variables
  vars = @process.environment_variables.merge({
    'PROC_NAME' => self.description,
    'PID_FILE' => self.pid_file_path,
    'APP_ROOT' => @process.config.root
  })
  vars['PORT'] = @port.to_s if @port
  vars
end

#failed? ⇒ Boolean

Has this failed?

Returns:

  • (Boolean) 


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# File 'lib/procodile/instance.rb', line 145

def failed?
  @failed ? true : false
end

#on_stop ⇒ Object

A method that will be called when this instance has been stopped and it isn’t going to be started again



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# File 'lib/procodile/instance.rb', line 168

def on_stop
  @started_at = nil
  @stopped = true
  tidy
end

#pid_file_path ⇒ Object

Return the path to this instance’s PID file



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# File 'lib/procodile/instance.rb', line 60

def pid_file_path
  File.join(@process.config.pid_root, "#{description}.pid")
end

#pid_from_file ⇒ Object

Return the PID that is in the instances process PID file



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# File 'lib/procodile/instance.rb', line 67

def pid_from_file
  if File.exist?(pid_file_path)
    pid = File.read(pid_file_path)
    pid.length > 0 ? pid.strip.to_i : nil
  else
    nil
  end
end

#respawns ⇒ Object

Return the number of times this process has been respawned in the last hour



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# File 'lib/procodile/instance.rb', line 274

def respawns
  if @respawns.nil? || @last_respawn.nil? || @last_respawn < (Time.now - @process.respawn_window)
    0
  else
    @respawns
  end
end

#restart ⇒ Object

Retarts the process using the appropriate method from the process configuraiton



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# File 'lib/procodile/instance.rb', line 185

def restart
  Procodile.log(@process.log_color, description, "Restarting using #{@process.restart_mode} mode")
  update_pid
  case @process.restart_mode
  when 'usr1', 'usr2'
    if running?
      ::Process.kill(@process.restart_mode.upcase, @pid)
      @tag = @supervisor.tag if @supervisor.tag
      Procodile.log(@process.log_color, description, "Sent #{@process.restart_mode.upcase} signal to process #{@pid}")
    else
      Procodile.log(@process.log_color, description, "Process not running already. Starting it.")
      on_stop
      @process.create_instance(@supervisor).start
    end
    self
  when 'start-term'
    new_instance = @process.create_instance(@supervisor)
    new_instance.start
    stop
    new_instance
  when 'term-start'
    stop
    new_instance = @process.create_instance(@supervisor)
    Thread.new do
      sleep 0.5 while running?
      new_instance.start
    end
    new_instance
  end
end

#running? ⇒ Boolean

Is this process running? Pass an option to check the given PID instead of the instance

Returns:

  • (Boolean) 


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# File 'lib/procodile/instance.rb', line 79

def running?
  if @pid
    ::Process.getpgid(@pid) ? true : false
  else
    false
  end
rescue Errno::ESRCH
  false
end

#start ⇒ Object

Start a new instance of this process



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# File 'lib/procodile/instance.rb', line 92

def start
  if stopping?
    Procodile.log(@process.log_color, description, "Process is stopped/stopping therefore cannot be started again.")
    return false
  end

  update_pid
  if running?
    Procodile.log(@process.log_color, description, "Already running with PID #{@pid}")
    nil
  else

    if @process.proxy? && @supervisor.tcp_proxy
      allocate_port
    end

    if self.process.log_path
      log_destination = File.open(self.process.log_path, 'a')
      io = nil
    else
      reader, writer = IO.pipe
      log_destination = writer
      io = reader
    end
    @tag = @supervisor.tag.dup if @supervisor.tag
    Dir.chdir(@process.config.root)
    @pid = ::Process.spawn(environment_variables, @process.command, :out => log_destination, :err => log_destination, :pgroup => true)
    log_destination.close
    File.open(pid_file_path, 'w') { |f| f.write(@pid.to_s + "\n") }
    @supervisor.add_instance(self, io)
    ::Process.detach(@pid)
    Procodile.log(@process.log_color, description, "Started with PID #{@pid}" + (@tag ? " (tagged with #{@tag})" : ''))
    @started_at = Time.now
  end
end

#status ⇒ Object

 Return the status of this instance



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# File 'lib/procodile/instance.rb', line 30

def status
  if stopped?
    'Stopped'
  elsif stopping?
    'Stopping'
  elsif running?
    'Running'
  elsif failed?
    'Failed'
  else
    'Unknown'
  end
end

#stop ⇒ Object

Send this signal the signal to stop and mark the instance in a state that tells us that we want it to be stopped.



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# File 'lib/procodile/instance.rb', line 153

def stop
  @stopping = Time.now
  update_pid
  if self.running?
    Procodile.log(@process.log_color, description, "Sending #{@process.term_signal} to #{@pid}")
    ::Process.kill(@process.term_signal, pid)
  else
    Procodile.log(@process.log_color, description, "Process already stopped")
  end
end

#stopped? ⇒ Boolean

 Is this stopped?

Returns:

  • (Boolean) 


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# File 'lib/procodile/instance.rb', line 138

def stopped?
  @stopped || false
end

#stopping? ⇒ Boolean

Is this instance supposed to be stopping/be stopped?

Returns:

  • (Boolean) 


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# File 'lib/procodile/instance.rb', line 131

def stopping?
  @stopping ? true : false
end

#tidy ⇒ Object

Tidy up when this process isn’t needed any more



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# File 'lib/procodile/instance.rb', line 177

def tidy
  FileUtils.rm_f(self.pid_file_path)
  Procodile.log(@process.log_color, description, "Removed PID file")
end

#to_hash ⇒ Object

Return this instance as a hash



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# File 'lib/procodile/instance.rb', line 297

def to_hash
  {
    :description => self.description,
    :pid => self.pid,
    :respawns => self.respawns,
    :status => self.status,
    :running => self.running?,
    :started_at => @started_at ? @started_at.to_i : nil,
    :tag => self.tag,
    :port => @port
  }
end

#update_pid ⇒ Object

Update the locally cached PID from that stored on the file system.



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# File 'lib/procodile/instance.rb', line 219

def update_pid
  pid_from_file = self.pid_from_file
  if pid_from_file && pid_from_file != @pid
    @pid = pid_from_file
    @started_at = File.mtime(self.pid_file_path)
    Procodile.log(@process.log_color, description, "PID file changed. Updated pid to #{@pid}")
    true
  else
    false
  end
end