New events and service calls now use a shared thread pool

homeassistant/util.py

@@ -1,5 +1,6 @@
 """ Helper methods for various modules. """
-
+import threading
+import Queue
 import datetime
 import re
 
@@ -53,3 +54,56 @@ def filter_entity_ids(entity_ids, domain_filter=None, strip_domain=False):
         for entity_id in entity_ids if
         not domain_filter or entity_id.startswith(domain_filter)
         ]
+
+
+def repr_helper(inp):
+    """ Helps creating a more readable string representation of objects. """
+    if isinstance(inp, dict):
+        return ", ".join(
+            repr_helper(key)+"="+repr_helper(item) for key, item in inp.items()
+            )
+    elif isinstance(inp, list):
+        return '[' + ', '.join(inp) + ']'
+    elif isinstance(inp, datetime.datetime):
+        return datetime_to_str(inp)
+    else:
+        return str(inp)
+
+
+# Reason why I decided to roll my own ThreadPool instead of using
+# multiprocessing.dummy.pool or even better, use multiprocessing.pool and
+# not be hurt by the GIL in the cpython interpreter:
+# 1. The built in threadpool does not allow me to create custom workers and so
+#    I would have to wrap every listener that I passed into it with code to log
+#    the exceptions. Saving a reference to the logger in the worker seemed
+#    like a more sane thing to do.
+# 2. Most event listeners are simple checks if attributes match. If the method
+#    that they will call takes a long time to complete it might be better to
+#    put that request in a seperate thread. This is for every component to
+#    decide on its own instead of enforcing it for everyone.
+class ThreadPool(object):
+    """ A simple queue-based thread pool.
+
+    Will initiate it's workers using worker(queue).start() """
+
+    # pylint: disable=too-few-public-methods
+    def __init__(self, worker_count, job_handler):
+        queue = self.queue = Queue.Queue()
+
+        for _ in xrange(worker_count):
+            worker = threading.Thread(target=_threadpool_worker,
+                                      args=(queue, job_handler))
+            worker.daemon = True
+            worker.start()
+
+    def add_job(self, *args):
+        """ Add a job to be sent to the workers. """
+        self.queue.put(args)
+
+
+def _threadpool_worker(queue, job_handler):
+    """ Provides the base functionality of a worker for the thread pool. """
+    while True:
+        job = queue.get()
+        job_handler(job)
+        queue.task_done()