Class: DirectoryWatcher::EmScanner

Inherits:
EventableScanner show all
Defined in:
lib/directory_watcher/em_scanner.rb

Overview

The EmScanner uses the EventMachine reactor loop to monitor changes to files in the watched directory. This scanner is more efficient than the pure Ruby scanner because it relies on the operating system kernel notifications instead of a periodic polling and stat of every file in the watched directory (the technique used by the Scanner class).

EventMachine cannot notify us when a file is added to the watched directory; therefore, added files are only picked up when we apply the glob pattern to the directory. This is done at the configured interval.

Notes:

* Kqueue does not generate notifications when "touch" is used to update
  a file's timestamp. This applies to Mac and BSD systems.

* New files are detected only when the watched directory is polled at the
  configured interval.

Defined Under Namespace

Classes: ScanTimer, Watcher

Instance Attribute Summary

Attributes inherited from EventableScanner

#iterations, #maximum_iterations, #watchers

Instance Method Summary collapse

Methods inherited from EventableScanner

#collection_queue, #finished_iterations?, #interval, #join, #on_modified, #on_removed, #on_scan, #pause, #paused?, #resume, #run, #running?, #start, #stop

Methods included from Logable

default_logger, #logger

Constructor Details

#initialize(config) ⇒ EmScanner

call-seq:

EmScanner.new( configuration )



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# File 'lib/directory_watcher/em_scanner.rb', line 40

def initialize( config )
  super(config)
end

Instance Method Details

#start_loop_with_attached_scan_timer ⇒ Object

Called by EventablScanner#start to start the loop up and attach the periodic timer that will poll the globs for new files.



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# File 'lib/directory_watcher/em_scanner.rb', line 47

def start_loop_with_attached_scan_timer
  return if @loop_thread
  unless EventMachine.reactor_running?
    @loop_thread = Thread.new {EventMachine.run}
    Thread.pass until EventMachine.reactor_running?
  end

  @timer = ScanTimer.new(self)
end

#stop_loop ⇒ Object

Called by EventableScanner#stop to stop the loop as part of the shutdown process.



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# File 'lib/directory_watcher/em_scanner.rb', line 60

def stop_loop
  if @loop_thread then
    EventMachine.next_tick do
      EventMachine.stop_event_loop
    end
    @loop_thread.kill
    @loop_thread = nil
  end
end