From 196dfd09d5a44dd432fd13ab87e93b87af7a8f64 Mon Sep 17 00:00:00 2001
From: Brian Korty <briank@aweber.com>
Date: Mon, 7 Aug 2017 13:08:20 -0400
Subject: [PATCH] Add HTTP_MAX_CLIENTS setting.

Add in support for the HTTP_MAX_CLIENTS environment variable to override the
default tornado settings.
---
 README.rst                        |  9 +++++++++
 sprockets/mixins/http/__init__.py |  8 ++++++++
 tests.py                          | 16 +++++++++++++---
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/README.rst b/README.rst
index bad252f..d9b0fd4 100644
--- a/README.rst
+++ b/README.rst
@@ -84,6 +84,15 @@ As with Tornado, to use the curl client which has numerous benefits:
        app.listen(8000)
        ioloop.IOLoop.current().start()
 
+Environment Variables
+---------------------
+
++------------------+----------------------------------------------------------+
+| HTTP_MAX_CLIENTS | An optional setting that specifies the maximum number of |
+|                  | simultaneous asynchronous HTTP requests. If not          |
+|                  | specified, the default Tornado value of 10 will be used. |
++------------------+----------------------------------------------------------+
+
 License
 -------
 ``sprockets.mixins.http`` is released under the `3-Clause BSD license <https://github.com/sprockets/sprockets.mixins.http/blob/master/LICENSE>`_.
diff --git a/sprockets/mixins/http/__init__.py b/sprockets/mixins/http/__init__.py
index 7b23a4c..e7a6628 100644
--- a/sprockets/mixins/http/__init__.py
+++ b/sprockets/mixins/http/__init__.py
@@ -8,6 +8,7 @@ requests.
 import collections
 import json
 import logging
+import os
 import socket
 import time
 
@@ -22,6 +23,7 @@ LOGGER = logging.getLogger(__name__)
 CONTENT_TYPE_JSON = headers.parse_content_type('application/json')
 CONTENT_TYPE_MSGPACK = headers.parse_content_type('application/msgpack')
 DEFAULT_USER_AGENT = 'sprockets.mixins.http/{}'.format(__version__)
+DEFAULT_MAX_CLIENTS = 10
 
 
 HTTPResponse = collections.namedtuple(
@@ -99,7 +101,13 @@ class HTTPClientMixin(object):
         if body:
             body = self._http_req_body_serialize(
                 body, request_headers['Content-Type'])
+
         client = httpclient.AsyncHTTPClient()
+
+        # Workaround for Tornado defect.
+        if hasattr(client, 'max_clients') and os.getenv('HTTP_MAX_CLIENTS'):
+            client.max_clients = int(os.getenv('HTTP_MAX_CLIENTS'))
+
         response, start_time = None, time.time()
         for attempt in range(0, self.MAX_HTTP_RETRIES):
             LOGGER.debug('%s %s (Attempt %i of %i) %r',
diff --git a/tests.py b/tests.py
index abbadc3..2d2ddd8 100644
--- a/tests.py
+++ b/tests.py
@@ -1,8 +1,9 @@
 import json
 import logging
+import os
 import uuid
 
-from tornado import httputil, testing, web
+from tornado import httpclient, httputil, testing, web
 import mock
 import umsgpack
 
@@ -400,6 +401,15 @@ class MixinTestCase(testing.AsyncHTTPTestCase):
             method='DELETE',
             body={'foo': 'bar', 'status_code': 200},
             allow_nonstandard_methods=True)
-
         self.assertTrue(response.ok)
-        self.assertEqual(response.code, 200)
+
+    @testing.gen_test()
+    def test_max_clients_settings_supported(self):
+        os.environ['HTTP_MAX_CLIENTS'] = '25'
+        response = yield self.mixin.http_fetch(
+            self.get_url('/test?foo=bar&status_code=200'))
+        self.assertTrue(response.ok)
+        del os.environ['HTTP_MAX_CLIENTS']
+        client = httpclient.AsyncHTTPClient()
+        self.assertEqual(client.max_clients, 25)
+