Disable case-changing behavior in Eventlet

RFC 2616 says that HTTP header fields are case-insensitive.  However, there are
some S3 clients who don't accept normalized header by Swift and Eventlet.  For
example, AWS Java SDK expects that an etag header is 'ETag', not 'Etag'.

This patch disables Eventlet's header capitalization so that the swift3
middleware can normalize the response headers as those clients expect.

Note that this change requires a fix for Eventlet, which will be included in
the next Eventlet release (v0.15).

Change-Id: I6d3428b0dafef776bdb3ebac7639b3126fa5e60d

swift/common/middleware/proxy_logging.py

@@ -253,10 +253,10 @@ class ProxyLoggingMiddleware(object):
                     break
             else:
                 if not chunk:
-                    start_response_args[0][1].append(('content-length', '0'))
+                    start_response_args[0][1].append(('Content-Length', '0'))
                 elif isinstance(iterable, list):
                     start_response_args[0][1].append(
-                        ('content-length', str(sum(len(i) for i in iterable))))
+                        ('Content-Length', str(sum(len(i) for i in iterable))))
             start_response(*start_response_args[0])
             req = Request(env)
 

swift/common/wsgi.py

@@ -16,6 +16,7 @@
 """WSGI tools for use with swift."""
 
 import errno
+import inspect
 import os
 import signal
 import time
@@ -386,7 +387,14 @@ def run_server(conf, logger, sock, global_conf=None):
     max_clients = int(conf.get('max_clients', '1024'))
     pool = RestrictedGreenPool(size=max_clients)
     try:
-        wsgi.server(sock, app, NullLogger(), custom_pool=pool)
+        # Disable capitalizing headers in Eventlet if possible.  This is
+        # necessary for the AWS SDK to work with swift3 middleware.
+        argspec = inspect.getargspec(wsgi.server)
+        if 'capitalize_response_headers' in argspec.args:
+            wsgi.server(sock, app, NullLogger(), custom_pool=pool,
+                        capitalize_response_headers=False)
+        else:
+            wsgi.server(sock, app, NullLogger(), custom_pool=pool)
     except socket.error as err:
         if err[0] != errno.EINVAL:
             raise

test/unit/common/test_wsgi.py

@@ -335,10 +335,11 @@ class TestWSGI(unittest.TestCase):
                             'modify_wsgi_pipeline'):
                 with mock.patch('swift.common.wsgi.wsgi') as _wsgi:
                     with mock.patch('swift.common.wsgi.eventlet') as _eventlet:
-                        conf = wsgi.appconfig(conf_file)
-                        logger = logging.getLogger('test')
-                        sock = listen(('localhost', 0))
-                        wsgi.run_server(conf, logger, sock)
+                        with mock.patch('swift.common.wsgi.inspect'):
+                            conf = wsgi.appconfig(conf_file)
+                            logger = logging.getLogger('test')
+                            sock = listen(('localhost', 0))
+                            wsgi.run_server(conf, logger, sock)
         self.assertEquals('HTTP/1.0',
                           _wsgi.HttpProtocol.default_request_version)
         self.assertEquals(30, _wsgi.WRITE_TIMEOUT)
@@ -356,6 +357,43 @@ class TestWSGI(unittest.TestCase):
         self.assert_('custom_pool' in kwargs)
         self.assertEquals(1000, kwargs['custom_pool'].size)
 
+    def test_run_server_with_latest_eventlet(self):
+        config = """
+        [DEFAULT]
+        swift_dir = TEMPDIR
+
+        [pipeline:main]
+        pipeline = proxy-server
+
+        [app:proxy-server]
+        use = egg:swift#proxy
+        """
+
+        def argspec_stub(server):
+            return mock.MagicMock(args=['capitalize_response_headers'])
+
+        contents = dedent(config)
+        with temptree(['proxy-server.conf']) as t:
+            conf_file = os.path.join(t, 'proxy-server.conf')
+            with open(conf_file, 'w') as f:
+                f.write(contents.replace('TEMPDIR', t))
+            _fake_rings(t)
+            with nested(
+                mock.patch('swift.proxy.server.Application.'
+                           'modify_wsgi_pipeline'),
+                mock.patch('swift.common.wsgi.wsgi'),
+                mock.patch('swift.common.wsgi.eventlet'),
+                mock.patch('swift.common.wsgi.inspect',
+                           getargspec=argspec_stub)) as (_, _wsgi, _, _):
+                conf = wsgi.appconfig(conf_file)
+                logger = logging.getLogger('test')
+                sock = listen(('localhost', 0))
+                wsgi.run_server(conf, logger, sock)
+
+        _wsgi.server.assert_called()
+        args, kwargs = _wsgi.server.call_args
+        self.assertEquals(kwargs.get('capitalize_response_headers'), False)
+
     def test_run_server_conf_dir(self):
         config_dir = {
             'proxy-server.conf.d/pipeline.conf': """
@@ -384,11 +422,12 @@ class TestWSGI(unittest.TestCase):
                 with mock.patch('swift.common.wsgi.wsgi') as _wsgi:
                     with mock.patch('swift.common.wsgi.eventlet') as _eventlet:
                         with mock.patch.dict('os.environ', {'TZ': ''}):
-                            conf = wsgi.appconfig(conf_dir)
-                            logger = logging.getLogger('test')
-                            sock = listen(('localhost', 0))
-                            wsgi.run_server(conf, logger, sock)
-                            self.assert_(os.environ['TZ'] is not '')
+                            with mock.patch('swift.common.wsgi.inspect'):
+                                conf = wsgi.appconfig(conf_dir)
+                                logger = logging.getLogger('test')
+                                sock = listen(('localhost', 0))
+                                wsgi.run_server(conf, logger, sock)
+                                self.assert_(os.environ['TZ'] is not '')
 
         self.assertEquals('HTTP/1.0',
                           _wsgi.HttpProtocol.default_request_version)