Class: ASF::AutoGC

Inherits:
Object
  • Object
show all
Defined in:
lib/whimsy/asf/rack.rb

Overview

‘use’ the following class in config.ru to automatically run Garbage Collection every ‘n’ requests, or ‘m’ minutes.

This tries to run garbage collection “out of band” (i.e., between requests), and when other requests are active (which can happen with threaded servers like Puma).

In addition to keeping memory usage bounded, this keeps the LDAP cache from going stale.

Constant Summary collapse

@@background = 
nil

Instance Method Summary collapse

Constructor Details

#initialize(app, frequency = 100, minutes = 15) ⇒ AutoGC

Returns a new instance of AutoGC.



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# File 'lib/whimsy/asf/rack.rb', line 101

def initialize(app, frequency=100, minutes=15)
  @app = app
  @frequency = frequency
  @request_count = 0
  @queue = Queue.new
  @mutex = Mutex.new

  if defined?(PhusionPassenger)
    # https://github.com/suyccom/yousell/blob/master/config.ru
    # https://www.phusionpassenger.com/library/indepth/ruby/out_of_band_work.html
    if PhusionPassenger.respond_to?(:require_passenger_lib)
      PhusionPassenger.require_passenger_lib 'rack/out_of_band_gc'
    else
      # Phusion Passenger < 4.0.33
      require 'phusion_passenger/rack/out_of_band_gc'
    end

    @passenger = PhusionPassenger::Rack::OutOfBandGc.new(app, frequency)
  end

  Thread.kill(@@background) if @@background

  if minutes
    # divide minutes by frequency and use the result to determine the
    # time between simulated requests
    @@background = Thread.new do
       seconds = minutes * 60.0 / frequency
       loop do
         sleep seconds
         maybe_perform_gc
       end
    end
  end
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/whimsy/asf/rack.rb', line 136

def call(env)
  @queue.push 1

  if @passenger
    @passenger.call(env)
  else
    # https://github.com/puma/puma/issues/450
    status, header, body = @app.call(env)

    if ary = env['rack.after_reply']
      ary << lambda {maybe_perform_gc}
    else
      Thread.new {sleep 0.1; maybe_perform_gc}
    end

    [status, header, body]
  end
ensure
  @queue.pop
end

#maybe_perform_gc ⇒ Object 



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# File 'lib/whimsy/asf/rack.rb', line 157

def maybe_perform_gc
  @mutex.synchronize do
    @request_count += 1
    if @queue.empty? and @request_count >= @frequency
      @request_count = 0
      disabled = GC.enable
      GC.start
      GC.disable if disabled
    end
  end
end