Prevent traceback in object-server on client disconnect

This only affects chunked transfers to replicated policies.
EC policies already have comparable error handling in
swift.common.utils._MultipartMimeFileLikeObject.read

See also: https://github.com/eventlet/eventlet/commit/c3ce3ee
but note that eventlet.wsgi.ChunkReadError and
swift.common.exceptions.ChunkReadError are entirely unrelated.

Change-Id: Ic9bcb73ea518c672a58a71d2b92152892f1ce2e4

swift/obj/server.py

@@ -407,7 +407,10 @@ class ObjectController(BaseStorageServer):
     def _make_timeout_reader(self, file_like):
         def timeout_reader():
             with ChunkReadTimeout(self.client_timeout):
-                return file_like.read(self.network_chunk_size)
+                try:
+                    return file_like.read(self.network_chunk_size)
+                except (IOError, ValueError):
+                    raise ChunkReadError
         return timeout_reader
 
     def _read_put_commit_message(self, mime_documents_iter):

test/unit/obj/test_server.py

@@ -1919,6 +1919,25 @@ class TestObjectController(unittest.TestCase):
             resp = req.get_response(self.object_controller)
             self.assertEqual(resp.status_int, 408)
 
+    def test_PUT_client_closed_connection(self):
+        class fake_input(object):
+            def read(self, *a, **kw):
+                # On client disconnect during a chunked transfer, eventlet
+                # may raise a ValueError (or ChunkReadError, following
+                # https://github.com/eventlet/eventlet/commit/c3ce3ee -- but
+                # that inherits from ValueError)
+                raise ValueError
+
+        timestamp = normalize_timestamp(time())
+        req = Request.blank(
+            '/sda1/p/a/c/o', environ={'REQUEST_METHOD': 'PUT'},
+            headers={'X-Timestamp': timestamp,
+                     'Content-Type': 'text/plain',
+                     'Content-Length': '6'})
+        req.environ['wsgi.input'] = fake_input()
+        resp = req.get_response(self.object_controller)
+        self.assertEqual(resp.status_int, 499)
+
     def test_PUT_system_metadata(self):
         # check that sysmeta is stored in diskfile
         timestamp = normalize_timestamp(time())