Class: God::Watch

Inherits:
Task
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/god/watch.rb

Constant Summary collapse

VALID_STATES = 
[:init, :up, :start, :restart, :down]
INITIAL_STATE = 
:init

Instance Attribute Summary collapse

Attributes inherited from Task

#autostart, #behaviors, #directory, #driver, #group, #initial_state, #interval, #metrics, #name, #state, #valid_states

Instance Method Summary collapse

Methods inherited from Task

#attach, #autostart?, #canonical_hash_form, #dest_desc, #detach, #handle_event, #handle_poll, #lifecycle, #log_line, #method_missing, #move, #notify, #prepare, #signal, #transition, #trigger, #trigger?, #unmonitor

Constructor Details

#initialize ⇒ Watch

Returns a new instance of Watch.



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# File 'lib/god/watch.rb', line 19

def initialize
  super
  
  @process = God::Process.new
  
  # valid states
  self.valid_states = VALID_STATES
  self.initial_state = INITIAL_STATE
  
  # no grace period by default
  self.grace = self.start_grace = self.stop_grace = self.restart_grace = 0
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method in the class God::Task

Instance Attribute Details

#grace ⇒ Object

config



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

def grace
  @grace
end

#restart_grace ⇒ Object

config



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

def restart_grace
  @restart_grace
end

#start_grace ⇒ Object

config



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

def start_grace
  @start_grace
end

#stop_grace ⇒ Object

config



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

def stop_grace
  @stop_grace
end

Instance Method Details

#action(a, c = nil) ⇒ Object

Actions



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# File 'lib/god/watch.rb', line 106

def action(a, c = nil)
  if Thread.current != self.driver.thread
    # called from outside Driver
    
    # send an async message to Driver
    self.driver.message(:action, [a, c])
  else
    # called from within Driver
    
    case a
    when :start
      call_action(c, :start)
      sleep(self.start_grace + self.grace)
    when :restart
      if self.restart
        call_action(c, :restart)
      else
        action(:stop, c)
        action(:start, c)
      end
      sleep(self.restart_grace + self.grace)
    when :stop
      call_action(c, :stop)
      sleep(self.stop_grace + self.grace)
    end
  end
  
  self
end

#behavior(kind) {|b| ... } ⇒ Object

Behavior

Yields:

  • (b) 


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# File 'lib/god/watch.rb', line 42

def behavior(kind)
  # create the behavior
  begin
    b = Behavior.generate(kind, self)
  rescue NoSuchBehaviorError => e
    abort e.message
  end
  
  # send to block so config can set attributes
  yield(b) if block_given?
  
  # abort if the Behavior is invalid, the Behavior will have printed
  # out its own error messages by now
  abort unless b.valid?
  
  self.behaviors << b
end

#call_action(condition, action) ⇒ Object 



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# File 'lib/god/watch.rb', line 136

def call_action(condition, action)
  # before
  before_items = self.behaviors
  before_items += [condition] if condition
  before_items.each do |b|
    info = b.send("before_#{action}")
    if info
      msg = "#{self.name} before_#{action}: #{info} (#{b.base_name})"
      applog(self, :info, msg)
    end
  end
  
  # log
  if self.send(action)
    msg = "#{self.name} #{action}: #{self.send(action).to_s}"
    applog(self, :info, msg)
  end
  
  @process.call_action(action)
  
  # after
  after_items = self.behaviors
  after_items += [condition] if condition
  after_items.each do |b|
    info = b.send("after_#{action}")
    if info
      msg = "#{self.name} after_#{action}: #{info} (#{b.base_name})"
      applog(self, :info, msg)
    end
  end
end

#monitor ⇒ Object

Enable monitoring



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# File 'lib/god/watch.rb', line 91

def monitor
  # start monitoring at the first available of the init or up states
  if !self.metrics[:init].empty?
    self.move(:init)
  else
    self.move(:up)
  end
end

#register! ⇒ Object

Registration



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# File 'lib/god/watch.rb', line 174

def register!
  God.registry.add(@process)
end

#restart_if ⇒ Object 



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# File 'lib/god/watch.rb', line 72

def restart_if
  self.transition(:up, :restart) do |on|
    yield(on)
  end
end

#start_if ⇒ Object

Simple mode



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# File 'lib/god/watch.rb', line 66

def start_if
  self.transition(:up, :start) do |on|
    yield(on)
  end
end

#stop_if ⇒ Object 



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# File 'lib/god/watch.rb', line 78

def stop_if 
  self.transition(:up, :stop) do |on| 
    yield(on) 
  end 
end

#unregister! ⇒ Object 



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# File 'lib/god/watch.rb', line 178

def unregister!
  God.registry.remove(@process)
end

#valid? ⇒ Boolean

Returns:

  • (Boolean) 


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

def valid?
  super && @process.valid?
end