Class: God::Driver

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

Overview

DriverEvent

Constant Summary collapse

INTERVAL = 
0.25

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(task) ⇒ Driver

Instantiate a new Driver and start the scheduler loop to handle events

+task+ is the Task this Driver belongs to

Returns Driver



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

def initialize(task)
  @task = task
  @events = []
  @ops = Queue.new
  
  @thread = Thread.new do
    loop do
      begin
        if !@ops.empty?
          self.handle_op
        elsif !@events.empty?
          self.handle_event
        else
          sleep INTERVAL
        end
      rescue Exception => e
        message = format("Unhandled exception in driver loop - (%s): %s\n%s",
                         e.class, e.message, e.backtrace.join("\n"))
        applog(nil, :fatal, message)
      end
    end
  end
end

Instance Attribute Details

#thread ⇒ Object (readonly)

Returns the value of attribute thread.



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

def thread
  @thread
end

Instance Method Details

#clear_events ⇒ Object

Clear all events for this Driver

Returns nothing



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# File 'lib/god/driver.rb', line 80

def clear_events
  @events.clear
end

#handle_event ⇒ Object

Handle the next event (poll condition) that is due

Returns nothing



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# File 'lib/god/driver.rb', line 65

def handle_event
  if @events.first.due?
    event = @events.shift
    @task.handle_poll(event.condition)
  end
  
  # don't sleep if there is a pending event and it is due
  unless @events.first && @events.first.due?
    sleep INTERVAL
  end
end

#handle_op ⇒ Object

Handle the next queued operation that was issued asynchronously

Returns nothing



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# File 'lib/god/driver.rb', line 57

def handle_op
  command = @ops.pop
  @task.send(command[0], *command[1])
end

#message(name, args = []) ⇒ Object

Queue an asynchronous message

+name+ is the Symbol name of the operation
+args+ is an optional Array of arguments

Returns nothing



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# File 'lib/god/driver.rb', line 89

def message(name, args = [])
  @ops.push([name, args])
end

#schedule(condition, delay = condition.interval) ⇒ Object

Create and schedule a new DriverEvent

+condition+ is the Condition
+delay+ is the number of seconds to delay (default: interval defined in condition)

Returns nothing



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# File 'lib/god/driver.rb', line 98

def schedule(condition, delay = condition.interval)
  applog(nil, :debug, "driver schedule #{condition} in #{delay} seconds")
  
  @events.concat([DriverEvent.new(condition, delay)])
  
  # sort events
  @events.sort! { |x, y| x.at <=> y.at }
end