scheduler: defer off-request work

Braulio Bhavamitra
1 parent 1a1eab27
Showing 2 changed files with 103 additions and 0 deletions Show diff stats
config/initializers/unicorn.rb
lib/noosfero/scheduler/defer.rb
@@ -0,0 +1,8 @@
+require_dependency 'scheduler/defer'
+
+if defined? Unicorn
+  ObjectSpace.each_object Unicorn::HttpServer do |s|
+    s.extend Scheduler::Defer::Unicorn
+  end
+end
+
@@ -0,0 +1,95 @@
+# based on https://github.com/discourse/discourse/blob/master/lib/scheduler/defer.rb
+
+module Scheduler
+  module Deferrable
+    def initialize
+      # FIXME: do some other way when not using Unicorn
+      @async = (not Rails.env.test?) and defined? Unicorn
+      @queue = Queue.new
+      @mutex = Mutex.new
+      @paused = false
+      @thread = nil
+    end
+
+    def pause
+      stop!
+      @paused = true
+    end
+
+    def resume
+      @paused = false
+    end
+
+    # for test
+    def async= val
+      @async = val
+    end
+
+    def later desc = nil, &blk
+      if @async
+        start_thread unless (@thread && @thread.alive?) || @paused
+        @queue << [blk, desc]
+      else
+        blk.call
+      end
+    end
+
+    def stop!
+      @thread.kill if @thread and @thread.alive?
+      @thread = nil
+    end
+
+    # test only
+    def stopped?
+      !(@thread and @thread.alive?)
+    end
+
+    def do_all_work
+      while !@queue.empty?
+        do_work _non_block=true
+      end
+    end
+
+    private
+
+    def start_thread
+      @mutex.synchronize do
+        return if @thread && @thread.alive?
+        @thread = Thread.new do
+          while true
+            do_work
+          end
+        end
+        @thread.priority = -2
+      end
+    end
+
+    # using non_block to match Ruby #deq
+    def do_work non_block=false
+      job, desc = @queue.deq non_block
+      begin
+        job.call
+      rescue => ex
+        ExceptionNotifier.notify_exception ex, message: "Running deferred code '#{desc}'"
+      end
+    rescue => ex
+      ExceptionNotifier.notify_exception ex, message: "Processing deferred code queue"
+    end
+  end
+
+  class Defer
+
+    module Unicorn
+      def process_client client
+        ::Scheduler::Defer.pause
+        super client
+        ::Scheduler::Defer.do_all_work
+        ::Scheduler::Defer.resume
+      end
+    end
+
+    extend Deferrable
+    initialize
+  end
+
+end
@@ -0,0 +1,8 @@		@@ -0,0 +1,8 @@
	1	+require_dependency 'scheduler/defer'
	2	+
	3	+if defined? Unicorn
	4	+ ObjectSpace.each_object Unicorn::HttpServer do \|s\|
	5	+ s.extend Scheduler::Defer::Unicorn
	6	+ end
	7	+end
	8	+
@@ -0,0 +1,95 @@		@@ -0,0 +1,95 @@
	1	+# based on https://github.com/discourse/discourse/blob/master/lib/scheduler/defer.rb
	2	+
	3	+module Scheduler
	4	+ module Deferrable
	5	+ def initialize
	6	+ # FIXME: do some other way when not using Unicorn
	7	+ @async = (not Rails.env.test?) and defined? Unicorn
	8	+ @queue = Queue.new
	9	+ @mutex = Mutex.new
	10	+ @paused = false
	11	+ @thread = nil
	12	+ end
	13	+
	14	+ def pause
	15	+ stop!
	16	+ @paused = true
	17	+ end
	18	+
	19	+ def resume
	20	+ @paused = false
	21	+ end
	22	+
	23	+ # for test
	24	+ def async= val
	25	+ @async = val
	26	+ end
	27	+
	28	+ def later desc = nil, &blk
	29	+ if @async
	30	+ start_thread unless (@thread && @thread.alive?) \|\| @paused
	31	+ @queue << [blk, desc]
	32	+ else
	33	+ blk.call
	34	+ end
	35	+ end
	36	+
	37	+ def stop!
	38	+ @thread.kill if @thread and @thread.alive?
	39	+ @thread = nil
	40	+ end
	41	+
	42	+ # test only
	43	+ def stopped?
	44	+ !(@thread and @thread.alive?)
	45	+ end
	46	+
	47	+ def do_all_work
	48	+ while !@queue.empty?
	49	+ do_work _non_block=true
	50	+ end
	51	+ end
	52	+
	53	+ private
	54	+
	55	+ def start_thread
	56	+ @mutex.synchronize do
	57	+ return if @thread && @thread.alive?
	58	+ @thread = Thread.new do
	59	+ while true
	60	+ do_work
	61	+ end
	62	+ end
	63	+ @thread.priority = -2
	64	+ end
	65	+ end
	66	+
	67	+ # using non_block to match Ruby #deq
	68	+ def do_work non_block=false
	69	+ job, desc = @queue.deq non_block
	70	+ begin
	71	+ job.call
	72	+ rescue => ex
	73	+ ExceptionNotifier.notify_exception ex, message: "Running deferred code '#{desc}'"
	74	+ end
	75	+ rescue => ex
	76	+ ExceptionNotifier.notify_exception ex, message: "Processing deferred code queue"
	77	+ end
	78	+ end
	79	+
	80	+ class Defer
	81	+
	82	+ module Unicorn
	83	+ def process_client client
	84	+ ::Scheduler::Defer.pause
	85	+ super client
	86	+ ::Scheduler::Defer.do_all_work
	87	+ ::Scheduler::Defer.resume
	88	+ end
	89	+ end
	90	+
	91	+ extend Deferrable
	92	+ initialize
	93	+ end
	94	+
	95	+end