Add client_socket_timeout option

Add a parameter to take advantage of the new(ish) eventlet socket timeout
behaviour.  Allows closing idle client connections after a period of
time, eg:

$ time nc localhost 8776
real    1m0.063s

Setting 'client_socket_timeout = 0' means do not timeout.

DocImpact:
Added client_socket_timeout option (default=0).

Conflicts:
        cinder/wsgi.py
        etc/cinder/cinder.conf.sample

Note: This patch is not 1:1 cherry-pick, I have changed the default value
of client_socket_timeout to 0.

Change-Id: If492810a2f10fa5954f8c8bb708b14be0b77fb90
Closes-bug: #1361360
Closes-bug: #1371022
(cherry picked from commit 08bfa77aec)

cinder/tests/test_wsgi.py

@@ -17,7 +17,10 @@
 """Unit tests for `cinder.wsgi`."""
 
 import os.path
+import re
+import socket
 import tempfile
+import time
 import urllib2
 
 import mock
@@ -151,7 +154,41 @@ class TestWSGIServer(test.TestCase):
 
         response = open_no_proxy('http://127.0.0.1:%d/' % server.port)
         self.assertEqual(greetings, response.read())
+        server.stop()
 
+    def test_client_socket_timeout(self):
+        CONF.set_default("client_socket_timeout", 0.1)
+        greetings = 'Hello, World!!!'
+
+        def hello_world(env, start_response):
+            start_response('200 OK', [('Content-Type', 'text/plain')])
+            return [greetings]
+
+        server = cinder.wsgi.Server("test_app", hello_world,
+                                    host="127.0.0.1", port=0)
+        server.start()
+
+        s = socket.socket()
+        s.connect(("127.0.0.1", server.port))
+
+        fd = s.makefile('rw')
+        fd.write(b'GET / HTTP/1.1\r\nHost: localhost\r\n\r\n')
+        fd.flush()
+
+        buf = fd.read()
+        self.assertTrue(re.search(greetings, buf))
+
+        s2 = socket.socket()
+        s2.connect(("127.0.0.1", server.port))
+        time.sleep(0.2)
+
+        fd = s2.makefile('rw')
+        fd.write(b'GET / HTTP/1.1\r\nHost: localhost\r\n\r\n')
+        fd.flush()
+
+        buf = fd.read()
+        # connection is closed so we get nothing from the server
+        self.assertFalse(buf)
         server.stop()
 
     def test_app_using_ssl(self):

cinder/wsgi.py

@@ -84,6 +84,11 @@ eventlet_opts = [
                 help='If False, closes the client socket connection '
                      'explicitly. Setting it to True to maintain backward '
                      'compatibility. Recommended setting is set it to False.'),
+    cfg.IntOpt('client_socket_timeout', default=0,
+               help="Timeout for client connections\' socket operations. "
+                    "If an incoming connection is idle for this number of "
+                    "seconds it will be closed. A value of \'0\' means "
+                    "wait forever."),
 ]
 
 CONF = cfg.CONF
@@ -112,6 +117,7 @@ class Server(object):
         """
         # Allow operators to customize http requests max header line size.
         eventlet.wsgi.MAX_HEADER_LINE = CONF.max_header_line
+        self.client_socket_timeout = CONF.client_socket_timeout or None
         self.name = name
         self.app = app
         self._host = host or "0.0.0.0"
@@ -235,7 +241,8 @@ class Server(object):
             'protocol': self._protocol,
             'custom_pool': self._pool,
             'log': self._wsgi_logger,
-            'keepalive': CONF.wsgi_keep_alive
+            'keepalive': CONF.wsgi_keep_alive,
+            'socket_timeout': self.client_socket_timeout
         }
 
         self._server = eventlet.spawn(**wsgi_kwargs)

etc/cinder/cinder.conf.sample

@@ -311,6 +311,12 @@
 # Recommended setting is set it to False. (boolean value)
 #wsgi_keep_alive=true
 
+# Timeout for client connections' socket operations. If an
+# incoming connection is idle for this number of seconds it
+# will be closed. A value of '0' means wait forever. (integer
+# value)
+#client_socket_timeout=0
+
 # Sets the value of TCP_KEEPALIVE (True/False) for each server
 # socket. (boolean value)
 #tcp_keepalive=true