diff --git a/swift/common/request_helpers.py b/swift/common/request_helpers.py index f12f876534..d42356b58b 100644 --- a/swift/common/request_helpers.py +++ b/swift/common/request_helpers.py @@ -454,6 +454,9 @@ class SegmentedIterable(object): self.logger.exception(_('ERROR: An error occurred ' 'while retrieving segments')) raise + finally: + if self.current_resp: + close_if_possible(self.current_resp.app_iter) def app_iter_range(self, *a, **kw): """ @@ -496,5 +499,4 @@ class SegmentedIterable(object): Called when the client disconnect. Ensure that the connection to the backend server is closed. """ - if self.current_resp: - close_if_possible(self.current_resp.app_iter) + close_if_possible(self.app_iter) diff --git a/test/unit/common/middleware/test_slo.py b/test/unit/common/middleware/test_slo.py index 32d49547d4..f1bafe11cf 100644 --- a/test/unit/common/middleware/test_slo.py +++ b/test/unit/common/middleware/test_slo.py @@ -26,7 +26,7 @@ from swift.common import swob, utils from swift.common.exceptions import ListingIterError, SegmentError from swift.common.middleware import slo from swift.common.swob import Request, Response, HTTPException -from swift.common.utils import quote, closing_if_possible +from swift.common.utils import quote, closing_if_possible, close_if_possible from test.unit.common.middleware.helpers import FakeSwift @@ -1944,6 +1944,68 @@ class TestSloGetManifest(SloTestCase): self.assertEqual(headers['X-Object-Meta-Fish'], 'Bass') self.assertEqual(body, '') + def test_generator_closure(self): + # Test that the SLO WSGI iterable closes its internal .app_iter when + # it receives a close() message. + # + # This is sufficient to fix a memory leak. The memory leak arises + # due to cyclic references involving a running generator; a running + # generator sometimes preventes the GC from collecting it in the + # same way that an object with a defined __del__ does. + # + # There are other ways to break the cycle and fix the memory leak as + # well; calling .close() on the generator is sufficient, but not + # necessary. However, having this test is better than nothing for + # preventing regressions. + leaks = [0] + + class LeakTracker(object): + def __init__(self, inner_iter): + leaks[0] += 1 + self.inner_iter = iter(inner_iter) + + def __iter__(self): + return self + + def next(self): + return next(self.inner_iter) + + def close(self): + leaks[0] -= 1 + close_if_possible(self.inner_iter) + + class LeakTrackingSegmentedIterable(slo.SegmentedIterable): + def _internal_iter(self, *a, **kw): + it = super( + LeakTrackingSegmentedIterable, self)._internal_iter( + *a, **kw) + return LeakTracker(it) + + status = [None] + headers = [None] + + def start_response(s, h, ei=None): + status[0] = s + headers[0] = h + + req = Request.blank( + '/v1/AUTH_test/gettest/manifest-abcd', + environ={'REQUEST_METHOD': 'GET', + 'HTTP_ACCEPT': 'application/json'}) + + # can't self.call_slo() here since we don't want to consume the + # whole body + with patch.object(slo, 'SegmentedIterable', + LeakTrackingSegmentedIterable): + app_resp = self.slo(req.environ, start_response) + self.assertEqual(status[0], '200 OK') # sanity check + body_iter = iter(app_resp) + chunk = next(body_iter) + self.assertEqual(chunk, 'aaaaa') # sanity check + + app_resp.close() + self.assertEqual(0, leaks[0]) + def test_head_manifest_is_efficient(self): req = Request.blank( '/v1/AUTH_test/gettest/manifest-abcd',