Fix StatHat::Reporter to allow #finish to avoid deadlocks waiting for worker threads

lib/stathat.rb

@@ -96,7 +96,7 @@ class Reporter
 
                 def initialize
                         @que = Queue.new
-                        @runlock = Mutex.new
+                        @running = false
                         run_pool()
                 end
 
@@ -105,6 +105,10 @@ def finish()
                         # XXX serialize queue?
                 end
 
+                def running?
+                  @running
+                end
+
                 def post_value(stat_key, user_key, value, timestamp, cb)
                         args = { :key => stat_key,
                                 :ukey => user_key,
@@ -139,12 +143,11 @@ def ez_post_count(stat_name, ezkey, count, timestamp, cb)
 
                 private
                 def run_pool
-                        @runlock.synchronize { @running = true }
+                        @running = true
                         @pool = []
                         5.times do |i|
                                 @pool[i] = Thread.new do
-                                        while true do
-                                                point = @que.pop
+                                        while (point = @que.pop) != :quit
                                                 # XXX check for error?
                                                 begin
                                                         resp = Common::send_to_stathat(point[:url], point[:args])
@@ -154,18 +157,21 @@ def run_pool
                                                 rescue
                                                         pp $!
                                                 end
-                                                @runlock.synchronize {
-                                                        break unless @running
-                                                }
                                         end
                                 end
                         end
                 end
 
                 def stop_pool()
-                        @runlock.synchronize {
-                                @running = false
-                        }
+                        @running = false
+
+                        # Each thread will stop after it receives
+                        # `:quit` instead of a hash of stat
+                        # information. Sending `@pool.length` quit
+                        # messages ensures that all threads will be
+                        # woken up, and thus avoid deadlocks.
+                        @pool.length.times { @que << :quit }
+
                         @pool.each do |th|
                                 th.join if th && th.alive?
                         end

test/test_stathat.rb

@@ -66,4 +66,18 @@ def test_classic_value_bad_keys_sync
                 assert_equal(r.msg, "invalid keys", "incorrect error message")
                 assert_equal(r.status, 500, "incorrect status code")
         end
+
+        def test_stat_on_finished_queue
+                reporter = StatHat::Reporter.instance
+                reporter.finish
+
+                assert !StatHat::API.ez_post_value("test ez count queued stat", "test@stathat.com", 12)
+        end
+
+        def test_reporter_finish
+                reporter = StatHat::Reporter.instance
+                reporter.finish
+
+                assert !reporter.running?
+        end
 end