Some defensive code against multiprocess related deadlocks

* Reinitialize logging in child processes so we don't inherit locks.
  Might be causing a deadlock we're seeing on Pro right now.

python_apps/airtime_analyzer/airtime_analyzer/analyzer_pipeline.py

@@ -30,6 +30,10 @@ class AnalyzerPipeline:
                                temporary randomly generated name, which is why we want
                                to know what the original name was.  
         """
+        # Might be super critical to initialize a separate log file here so that we 
+        # don't inherit logging/locks from the parent process. Supposedly
+        # this can lead to Bad Things (deadlocks): http://bugs.python.org/issue6721
+        AnalyzerPipeline.setup_logging()
         try:
             if not isinstance(queue, multiprocessing.queues.Queue):
                 raise TypeError("queue must be a multiprocessing.Queue()")
@@ -59,4 +63,10 @@ class AnalyzerPipeline:
             logging.exception(e) 
             raise e
 
-
+    @staticmethod
+    def setup_logging():
+        _LOG_PATH = "/var/log/airtime/airtime_analyzer_pipeline.log"
+        FORMAT = "%(asctime)s [%(module)s] [%(levelname)-5.5s]  %(message)s"
+        logging.basicConfig(filename=_LOG_PATH,level=logging.DEBUG, format=FORMAT)
+        #rootLogger = logging.getLogger()
+        #rootLogger.setFormatter(logFormatter)

python_apps/airtime_analyzer/airtime_analyzer/message_listener.py

@@ -212,6 +212,10 @@ class MessageListener:
             logging.info(results)
         else:
             raise Exception("Analyzer process terminated unexpectedly.")
+       
+        # Ensure our queue doesn't fill up and block due to unexpected behaviour. Defensive code.
+        while not q.empty():
+            q.get()
 
         return results