From dd91ce1f399c820ec4583f63b9067257680d8194 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jannes=20H=C3=B6ke?= <jhoeke@uni-bremen.de>
Date: Mon, 30 May 2016 13:09:23 +0200
Subject: [PATCH] use single queue for thread pool, initialize connection pool
 with n+3

---
 telegram/ext/dispatcher.py | 46 +++++++++++++++++++-------------------
 telegram/ext/updater.py    |  4 ++++
 telegram/utils/request.py  |  5 ++++-
 3 files changed, 31 insertions(+), 24 deletions(-)

diff --git a/telegram/ext/dispatcher.py b/telegram/ext/dispatcher.py
index f6d068bdb..72f206236 100644
--- a/telegram/ext/dispatcher.py
+++ b/telegram/ext/dispatcher.py
@@ -20,37 +20,45 @@
 
 import logging
 from functools import wraps
-from threading import Thread, BoundedSemaphore, Lock, Event  # , current_thread
+from threading import Thread, Lock, Event  # , current_thread
 from time import sleep
 from queue import Queue, Empty
 
 from telegram import (TelegramError, NullHandler)
+from telegram.utils import request
 from telegram.ext.handler import Handler
 from telegram.utils.deprecate import deprecate
 
 logging.getLogger(__name__).addHandler(NullHandler())
 
-semaphore = None
-async_threads = list()
-""":type: list[tuple(Thread, Event, Queue)]"""
+async_queue = Queue()
+async_threads = set()
+""":type: set[Thread]"""
 async_lock = Lock()
 DEFAULT_GROUP = 0
 
 
-def pooled(event, queue):
+def pooled():
     """
     A wrapper to run a thread in a thread pool
     """
     while True:
         logging.info('Waiting for function')
-        func, args, kwargs = queue.get()
+
+        try:
+            func, args, kwargs = async_queue.get()
+
+        except TypeError:
+            break
+
         logging.info('Got function')
+
         try:
             func(*args, **kwargs)
             logging.info('Executed function')
-        finally:
-            event.clear()
-            semaphore.release()
+
+        except:
+            logging.exception("Async function raised exception")
 
 
 def run_async(func):
@@ -72,12 +80,7 @@ def run_async(func):
         """
         A wrapper to run a function in a thread
         """
-        semaphore.acquire()
-        for thread, event, queue in async_threads:
-            if not event.is_set():
-                event.set()
-                queue.put((func, pargs, kwargs))
-                break
+        async_queue.put((func, pargs, kwargs))
 
     return async_func
 
@@ -108,17 +111,14 @@ class Dispatcher(object):
         self.__stop_event = Event()
         self.__exception_event = exception_event or Event()
 
-        global semaphore
-        if not semaphore:
-            semaphore = BoundedSemaphore(value=workers)
+        if not len(async_threads):
+            request.CON_POOL_SIZE = workers + 3
             for i in range(workers):
-                event = Event()
-                queue = Queue()
-                thread = Thread(target=pooled, args=(event, queue))
-                async_threads.append((thread, event, queue))
+                thread = Thread(target=pooled)
+                async_threads.add(thread)
                 thread.start()
         else:
-            self.logger.debug('Semaphore already initialized, skipping.')
+            self.logger.debug('Thread pool already initialized, skipping.')
 
     def start(self):
         """
diff --git a/telegram/ext/updater.py b/telegram/ext/updater.py
index df70275e5..2f92fe43f 100644
--- a/telegram/ext/updater.py
+++ b/telegram/ext/updater.py
@@ -375,6 +375,10 @@ class Updater(object):
         with dispatcher.async_lock:
             threads = list(dispatcher.async_threads)
         total = len(threads)
+
+        for i in range(total):
+            dispatcher.async_queue.put(0)
+
         for i, thr in enumerate(threads):
             self.logger.debug('Waiting for async thread {0}/{1} to end'.format(i, total))
             thr.join()
diff --git a/telegram/utils/request.py b/telegram/utils/request.py
index 5926add9f..5145685b6 100644
--- a/telegram/utils/request.py
+++ b/telegram/utils/request.py
@@ -27,6 +27,7 @@ from telegram import (InputFile, TelegramError)
 from telegram.error import Unauthorized, NetworkError, TimedOut, BadRequest
 
 _CON_POOL = None
+CON_POOL_SIZE = 1
 
 
 def _get_con_pool():
@@ -34,7 +35,9 @@ def _get_con_pool():
         return _CON_POOL
 
     global _CON_POOL
-    _CON_POOL = urllib3.PoolManager(10, cert_reqs='CERT_REQUIRED', ca_certs=certifi.where())
+    _CON_POOL = urllib3.PoolManager(CON_POOL_SIZE,
+                                    cert_reqs='CERT_REQUIRED',
+                                    ca_certs=certifi.where())
     return _CON_POOL