1 # -*- encoding: binary -*-
3 # Runs GC after requests, after closing the client socket and
4 # before attempting to accept more connections.
6 # This shouldn't hurt overall performance as long as the server cluster
7 # is at <50% CPU capacity, and improves the performance of most memory
8 # intensive requests. This serves to improve _client-visible_
9 # performance (possibly at the cost of overall performance).
11 # Increasing the number of +worker_processes+ may be necessary to
12 # improve average client response times because some of your workers
13 # will be busy doing GC and unable to service clients. Think of
14 # using more workers with this module as a poor man's concurrent GC.
16 # We'll call GC after each request is been written out to the socket, so
17 # the client never sees the extra GC hit it.
19 # This middleware is _only_ effective for applications that use a lot
20 # of memory, and will hurt simpler apps/endpoints that can process
21 # multiple requests before incurring GC.
23 # This middleware is only designed to work with unicorn, as it harms
24 # performance with keepalive-enabled servers.
26 # Example (in config.ru):
28 # require 'unicorn/oob_gc'
30 # # GC ever two requests that hit /expensive/foo or /more_expensive/foo
31 # # in your app. By default, this will GC once every 5 requests
32 # # for all endpoints in your app
33 # use Unicorn::OobGC, 2, %r{\A/(?:expensive/foo|more_expensive/foo)}
35 # Feedback from users of early implementations of this module:
36 # * http://comments.gmane.org/gmane.comp.lang.ruby.unicorn.general/486
37 # * http://article.gmane.org/gmane.comp.lang.ruby.unicorn.general/596
40 # this pretends to be Rack middleware because it used to be
41 # But we need to hook into unicorn internals so we need to close
42 # the socket before clearing the request env.
44 # +interval+ is the number of requests matching the +path+ regular
45 # expression before invoking GC.
46 def self.new(app, interval = 5, path = %r{\A/})
48 self.const_set :OOBGC_PATH, path
49 self.const_set :OOBGC_INTERVAL, interval
50 ObjectSpace.each_object(Unicorn::HttpServer) do |s|
52 self.const_set :OOBGC_ENV, s.instance_variable_get(:@request).env
54 app # pretend to be Rack middleware since it was in the past
58 PATH_INFO = "PATH_INFO"
59 def process_client(client)
60 super(client) # Unicorn::HttpServer#process_client
61 if OOBGC_PATH =~ OOBGC_ENV[PATH_INFO] && ((@@nr -= 1) <= 0)
66 GC.disable if disabled