From: Ben Darnell <ben@bendarnell.com>
Date: Sat, 5 May 2018 18:26:52 +0000 (-0400)
Subject: wsgi: Document workaround for asyncio on multithreaded WSGI containers
X-Git-Tag: v5.1.0b1~20^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=16a3567b68f23ae4386eaf881f6a8584968d33d9;p=thirdparty%2Ftornado.git

wsgi: Document workaround for asyncio on multithreaded WSGI containers

Fixes #2371
---

diff --git a/tornado/wsgi.py b/tornado/wsgi.py
index 892c0a929..beda0b9aa 100644
--- a/tornado/wsgi.py
+++ b/tornado/wsgi.py
@@ -181,6 +181,15 @@ class WSGIAdapter(object):
     that it is not possible to use `.AsyncHTTPClient`, or the
     `tornado.auth` or `tornado.websocket` modules.
 
+    In multithreaded WSGI servers on Python 3, it may be necessary to
+    permit `asyncio` to create event loops on any thread. Run the
+    following at startup (typically import time for WSGI
+    applications)::
+
+        import asyncio
+        from tornado.platform.asyncio import AnyThreadEventLoopPolicy
+        asyncio.set_event_loop_policy(AnyThreadEventLoopPolicy())
+
     .. versionadded:: 4.0
 
     .. deprecated:: 5.1