Merge "Compare each chunk of large objects when downloading"

2 files changed, 425 insertions, 12 deletions

diff --git a/swiftclient/service.py b/swiftclient/service.py
index d607d65..90daf5a 100644
--- a/swiftclient/service.py
+++ b/swiftclient/service.py
@@ -974,8 +974,7 @@ class SwiftService(object):
             for o_down in interruptable_as_completed(o_downs):
                 yield o_down.result()
 
-    @staticmethod
-    def _download_object_job(conn, container, obj, options):
+    def _download_object_job(self, conn, container, obj, options):
         out_file = options['out_file']
         results_dict = {}
 
@@ -984,7 +983,10 @@ class SwiftService(object):
         pseudodir = False
         path = join(container, obj) if options['yes_all'] else obj
         path = path.lstrip(os_path_sep)
-        if options['skip_identical'] and out_file != '-':
+        options['skip_identical'] = (options['skip_identical'] and
+                                     out_file != '-')
+
+        if options['skip_identical']:
             filename = out_file if out_file else path
             try:
                 fp = open(filename, 'rb')
@@ -1002,10 +1004,55 @@ class SwiftService(object):
 
         try:
             start_time = time()
-            headers, body = \
-                conn.get_object(container, obj, resp_chunk_size=65536,
-                                headers=req_headers,
-                                response_dict=results_dict)
+            get_args = {'resp_chunk_size': 65536,
+                        'headers': req_headers,
+                        'response_dict': results_dict}
+            if options['skip_identical']:
+                # Assume the file is a large object; if we're wrong, the query
+                # string is ignored and the If-None-Match header will trigger
+                # the behavior we want
+                get_args['query_string'] = 'multipart-manifest=get'
+
+            try:
+                headers, body = conn.get_object(container, obj, **get_args)
+            except ClientException as e:
+                if not options['skip_identical']:
+                    raise
+                if e.http_status != 304:  # Only handling Not Modified
+                    raise
+
+                headers = results_dict['headers']
+                if 'x-object-manifest' in headers:
+                    # DLO: most likely it has more than one page worth of
+                    #      segments and we have an empty file locally
+                    body = []
+                elif config_true_value(headers.get('x-static-large-object')):
+                    # SLO: apparently we have a copy of the manifest locally?
+                    #      provide no chunking data to force a fresh download
+                    body = [b'[]']
+                else:
+                    # Normal object: let it bubble up
+                    raise
+
+            if options['skip_identical']:
+                if config_true_value(headers.get('x-static-large-object')) or \
+                        'x-object-manifest' in headers:
+                    # The request was chunked, so stitch it back together
+                    chunk_data = self._get_chunk_data(conn, container, obj,
+                                                      headers, b''.join(body))
+                else:
+                    chunk_data = None
+
+                if chunk_data is not None:
+                    if self._is_identical(chunk_data, filename):
+                        raise ClientException('Large object is identical',
+                                              http_status=304)
+
+                    # Large objects are different; start the real download
+                    del get_args['query_string']
+                    get_args['response_dict'].clear()
+                    headers, body = conn.get_object(container, obj, **get_args)
+
             headers_receipt = time()
 
             obj_body = _SwiftReader(path, body, headers)
@@ -1503,7 +1550,7 @@ class SwiftService(object):
                 results_queue.put(res)
             return res
 
-    def _get_chunk_data(self, conn, container, obj, headers):
+    def _get_chunk_data(self, conn, container, obj, headers, manifest=None):
         chunks = []
         if 'x-object-manifest' in headers:
             scontainer, sprefix = headers['x-object-manifest'].split('/', 1)
@@ -1513,10 +1560,11 @@ class SwiftService(object):
                 else:
                     raise part["error"]
         elif config_true_value(headers.get('x-static-large-object')):
-            manifest_headers, manifest_data = conn.get_object(
-                container, obj, query_string='multipart-manifest=get')
-            manifest_data = parse_api_response(manifest_headers, manifest_data)
-            for chunk in manifest_data:
+            if manifest is None:
+                headers, manifest = conn.get_object(
+                    container, obj, query_string='multipart-manifest=get')
+            manifest = parse_api_response(headers, manifest)
+            for chunk in manifest:
                 if chunk.get('sub_slo'):
                     scont, sobj = chunk['name'].lstrip('/').split('/', 1)
                     chunks.extend(self._get_chunk_data(
diff --git a/tests/unit/test_service.py b/tests/unit/test_service.py
index 1e0d96d..74a6ce3 100644
--- a/tests/unit/test_service.py
+++ b/tests/unit/test_service.py
@@ -988,3 +988,368 @@ class TestServiceUpload(testtools.TestCase):
                           marker="test_o/prefix/02", delimiter=None),
             ]
             mock_conn.get_container.assert_has_calls(expected)
+
+
+class TestServiceDownload(testtools.TestCase):
+
+    def _assertDictEqual(self, a, b, m=None):
+        # assertDictEqual is not available in py2.6 so use a shallow check
+        # instead
+        if not m:
+            m = '{0} != {1}'.format(a, b)
+
+        if hasattr(self, 'assertDictEqual'):
+            self.assertDictEqual(a, b, m)
+        else:
+            self.assertTrue(isinstance(a, dict), m)
+            self.assertTrue(isinstance(b, dict), m)
+            self.assertEqual(len(a), len(b), m)
+            for k, v in a.items():
+                self.assertIn(k, b, m)
+                self.assertEqual(b[k], v, m)
+
+    def test_download_object_job_skip_identical(self):
+        with tempfile.NamedTemporaryFile() as f:
+            f.write(b'a' * 30)
+            f.flush()
+
+            err = swiftclient.ClientException('Object GET failed',
+                                              http_status=304)
+
+            def fake_get(*args, **kwargs):
+                kwargs['response_dict']['headers'] = {}
+                raise err
+
+            mock_conn = mock.Mock()
+            mock_conn.get_object.side_effect = fake_get
+            type(mock_conn).attempts = mock.PropertyMock(return_value=2)
+            expected_r = {
+                'action': 'download_object',
+                'container': 'test_c',
+                'object': 'test_o',
+                'success': False,
+                'error': err,
+                'response_dict': {'headers': {}},
+                'path': 'test_o',
+                'pseudodir': False,
+                'attempts': 2,
+            }
+
+            s = SwiftService()
+            r = s._download_object_job(conn=mock_conn,
+                                       container='test_c',
+                                       obj='test_o',
+                                       options={'out_file': f.name,
+                                                'header': {},
+                                                'yes_all': False,
+                                                'skip_identical': True})
+            self._assertDictEqual(r, expected_r)
+
+            self.assertEqual(mock_conn.get_object.call_count, 1)
+            mock_conn.get_object.assert_called_with(
+                'test_c',
+                'test_o',
+                resp_chunk_size=65536,
+                headers={'If-None-Match': md5(b'a' * 30).hexdigest()},
+                query_string='multipart-manifest=get',
+                response_dict=expected_r['response_dict'])
+
+    def test_download_object_job_skip_identical_dlo(self):
+        with tempfile.NamedTemporaryFile() as f:
+            f.write(b'a' * 30)
+            f.flush()
+            on_disk_md5 = md5(b'a' * 30).hexdigest()
+            segment_md5 = md5(b'a' * 10).hexdigest()
+
+            mock_conn = mock.Mock()
+            mock_conn.get_object.return_value = (
+                {'x-object-manifest': 'test_c_segments/test_o/prefix'}, [b''])
+            mock_conn.get_container.side_effect = [
+                (None, [{'name': 'test_o/prefix/1',
+                         'bytes': 10, 'hash': segment_md5},
+                        {'name': 'test_o/prefix/2',
+                         'bytes': 10, 'hash': segment_md5}]),
+                (None, [{'name': 'test_o/prefix/3',
+                         'bytes': 10, 'hash': segment_md5}]),
+                (None, [])]
+
+            type(mock_conn).attempts = mock.PropertyMock(return_value=2)
+            expected_r = {
+                'action': 'download_object',
+                'container': 'test_c',
+                'object': 'test_o',
+                'success': False,
+                'response_dict': {},
+                'path': 'test_o',
+                'pseudodir': False,
+                'attempts': 2,
+            }
+
+            s = SwiftService()
+            with mock.patch('swiftclient.service.get_conn',
+                            return_value=mock_conn):
+                r = s._download_object_job(conn=mock_conn,
+                                           container='test_c',
+                                           obj='test_o',
+                                           options={'out_file': f.name,
+                                                    'header': {},
+                                                    'yes_all': False,
+                                                    'skip_identical': True})
+
+            err = r.pop('error')
+            self.assertEqual("Large object is identical", err.msg)
+            self.assertEqual(304, err.http_status)
+
+            self._assertDictEqual(r, expected_r)
+
+            self.assertEqual(mock_conn.get_object.call_count, 1)
+            mock_conn.get_object.assert_called_with(
+                'test_c',
+                'test_o',
+                resp_chunk_size=65536,
+                headers={'If-None-Match': on_disk_md5},
+                query_string='multipart-manifest=get',
+                response_dict=expected_r['response_dict'])
+            self.assertEqual(mock_conn.get_container.mock_calls, [
+                mock.call('test_c_segments',
+                          delimiter=None,
+                          prefix='test_o/prefix',
+                          marker=''),
+                mock.call('test_c_segments',
+                          delimiter=None,
+                          prefix='test_o/prefix',
+                          marker='test_o/prefix/2'),
+                mock.call('test_c_segments',
+                          delimiter=None,
+                          prefix='test_o/prefix',
+                          marker='test_o/prefix/3')])
+
+    def test_download_object_job_skip_identical_nested_slo(self):
+        with tempfile.NamedTemporaryFile() as f:
+            f.write(b'a' * 30)
+            f.flush()
+            on_disk_md5 = md5(b'a' * 30).hexdigest()
+
+            seg_etag = md5(b'a' * 10).hexdigest()
+            submanifest = "[%s]" % ",".join(
+                ['{"bytes":10,"hash":"%s"}' % seg_etag] * 2)
+            submanifest_etag = md5(seg_etag.encode('ascii') * 2).hexdigest()
+            manifest = "[%s]" % ",".join([
+                '{"sub_slo":true,"name":"/test_c_segments/test_sub_slo",'
+                '"bytes":20,"hash":"%s"}' % submanifest_etag,
+                '{"bytes":10,"hash":"%s"}' % seg_etag])
+
+            mock_conn = mock.Mock()
+            mock_conn.get_object.side_effect = [
+                ({'x-static-large-object': True,
+                  'content-length': 30,
+                  'etag': md5(submanifest_etag.encode('ascii') +
+                              seg_etag.encode('ascii')).hexdigest()},
+                 [manifest.encode('ascii')]),
+                ({'x-static-large-object': True,
+                  'content-length': 20,
+                  'etag': submanifest_etag},
+                 submanifest.encode('ascii'))]
+
+            type(mock_conn).attempts = mock.PropertyMock(return_value=2)
+            expected_r = {
+                'action': 'download_object',
+                'container': 'test_c',
+                'object': 'test_o',
+                'success': False,
+                'response_dict': {},
+                'path': 'test_o',
+                'pseudodir': False,
+                'attempts': 2,
+            }
+
+            s = SwiftService()
+            with mock.patch('swiftclient.service.get_conn',
+                            return_value=mock_conn):
+                r = s._download_object_job(conn=mock_conn,
+                                           container='test_c',
+                                           obj='test_o',
+                                           options={'out_file': f.name,
+                                                    'header': {},
+                                                    'yes_all': False,
+                                                    'skip_identical': True})
+
+            err = r.pop('error')
+            self.assertEqual("Large object is identical", err.msg)
+            self.assertEqual(304, err.http_status)
+
+            self._assertDictEqual(r, expected_r)
+            self.assertEqual(mock_conn.get_object.mock_calls, [
+                mock.call('test_c',
+                          'test_o',
+                          resp_chunk_size=65536,
+                          headers={'If-None-Match': on_disk_md5},
+                          query_string='multipart-manifest=get',
+                          response_dict={}),
+                mock.call('test_c_segments',
+                          'test_sub_slo',
+                          query_string='multipart-manifest=get')])
+
+    def test_download_object_job_skip_identical_diff_dlo(self):
+        with tempfile.NamedTemporaryFile() as f:
+            f.write(b'a' * 30)
+            f.write(b'b')
+            f.flush()
+            on_disk_md5 = md5(b'a' * 30 + b'b').hexdigest()
+            segment_md5 = md5(b'a' * 10).hexdigest()
+
+            mock_conn = mock.Mock()
+            mock_conn.get_object.side_effect = [
+                ({'x-object-manifest': 'test_c_segments/test_o/prefix'},
+                 [b'']),
+                ({'x-object-manifest': 'test_c_segments/test_o/prefix'},
+                 [b'a' * 30])]
+            mock_conn.get_container.side_effect = [
+                (None, [{'name': 'test_o/prefix/1',
+                         'bytes': 10, 'hash': segment_md5},
+                        {'name': 'test_o/prefix/2',
+                         'bytes': 10, 'hash': segment_md5}]),
+                (None, [{'name': 'test_o/prefix/3',
+                         'bytes': 10, 'hash': segment_md5}]),
+                (None, [])]
+
+            type(mock_conn).attempts = mock.PropertyMock(return_value=2)
+            type(mock_conn).auth_end_time = mock.PropertyMock(return_value=14)
+            expected_r = {
+                'action': 'download_object',
+                'container': 'test_c',
+                'object': 'test_o',
+                'success': True,
+                'response_dict': {},
+                'path': 'test_o',
+                'pseudodir': False,
+                'read_length': 30,
+                'attempts': 2,
+                'start_time': 0,
+                'headers_receipt': 1,
+                'finish_time': 2,
+                'auth_end_time': mock_conn.auth_end_time,
+            }
+
+            s = SwiftService()
+            with mock.patch('swiftclient.service.time', side_effect=range(3)):
+                with mock.patch('swiftclient.service.get_conn',
+                                return_value=mock_conn):
+                    r = s._download_object_job(
+                        conn=mock_conn,
+                        container='test_c',
+                        obj='test_o',
+                        options={'out_file': f.name,
+                                 'header': {},
+                                 'no_download': True,
+                                 'yes_all': False,
+                                 'skip_identical': True})
+
+            self._assertDictEqual(r, expected_r)
+
+            self.assertEqual(mock_conn.get_container.mock_calls, [
+                mock.call('test_c_segments',
+                          delimiter=None,
+                          prefix='test_o/prefix',
+                          marker=''),
+                mock.call('test_c_segments',
+                          delimiter=None,
+                          prefix='test_o/prefix',
+                          marker='test_o/prefix/2'),
+                mock.call('test_c_segments',
+                          delimiter=None,
+                          prefix='test_o/prefix',
+                          marker='test_o/prefix/3')])
+            self.assertEqual(mock_conn.get_object.mock_calls, [
+                mock.call('test_c',
+                          'test_o',
+                          resp_chunk_size=65536,
+                          headers={'If-None-Match': on_disk_md5},
+                          query_string='multipart-manifest=get',
+                          response_dict={}),
+                mock.call('test_c',
+                          'test_o',
+                          resp_chunk_size=65536,
+                          headers={'If-None-Match': on_disk_md5},
+                          response_dict={})])
+
+    def test_download_object_job_skip_identical_diff_nested_slo(self):
+        with tempfile.NamedTemporaryFile() as f:
+            f.write(b'a' * 29)
+            f.flush()
+            on_disk_md5 = md5(b'a' * 29).hexdigest()
+
+            seg_etag = md5(b'a' * 10).hexdigest()
+            submanifest = "[%s]" % ",".join(
+                ['{"bytes":10,"hash":"%s"}' % seg_etag] * 2)
+            submanifest_etag = md5(seg_etag.encode('ascii') * 2).hexdigest()
+            manifest = "[%s]" % ",".join([
+                '{"sub_slo":true,"name":"/test_c_segments/test_sub_slo",'
+                '"bytes":20,"hash":"%s"}' % submanifest_etag,
+                '{"bytes":10,"hash":"%s"}' % seg_etag])
+
+            mock_conn = mock.Mock()
+            mock_conn.get_object.side_effect = [
+                ({'x-static-large-object': True,
+                  'content-length': 30,
+                  'etag': md5(submanifest_etag.encode('ascii') +
+                              seg_etag.encode('ascii')).hexdigest()},
+                 [manifest.encode('ascii')]),
+                ({'x-static-large-object': True,
+                  'content-length': 20,
+                  'etag': submanifest_etag},
+                 submanifest.encode('ascii')),
+                ({'x-static-large-object': True,
+                  'content-length': 30,
+                  'etag': md5(submanifest_etag.encode('ascii') +
+                              seg_etag.encode('ascii')).hexdigest()},
+                 [b'a' * 30])]
+
+            type(mock_conn).attempts = mock.PropertyMock(return_value=2)
+            type(mock_conn).auth_end_time = mock.PropertyMock(return_value=14)
+            expected_r = {
+                'action': 'download_object',
+                'container': 'test_c',
+                'object': 'test_o',
+                'success': True,
+                'response_dict': {},
+                'path': 'test_o',
+                'pseudodir': False,
+                'read_length': 30,
+                'attempts': 2,
+                'start_time': 0,
+                'headers_receipt': 1,
+                'finish_time': 2,
+                'auth_end_time': mock_conn.auth_end_time,
+            }
+
+            s = SwiftService()
+            with mock.patch('swiftclient.service.time', side_effect=range(3)):
+                with mock.patch('swiftclient.service.get_conn',
+                                return_value=mock_conn):
+                    r = s._download_object_job(
+                        conn=mock_conn,
+                        container='test_c',
+                        obj='test_o',
+                        options={'out_file': f.name,
+                                 'header': {},
+                                 'no_download': True,
+                                 'yes_all': False,
+                                 'skip_identical': True})
+
+            self._assertDictEqual(r, expected_r)
+            self.assertEqual(mock_conn.get_object.mock_calls, [
+                mock.call('test_c',
+                          'test_o',
+                          resp_chunk_size=65536,
+                          headers={'If-None-Match': on_disk_md5},
+                          query_string='multipart-manifest=get',
+                          response_dict={}),
+                mock.call('test_c_segments',
+                          'test_sub_slo',
+                          query_string='multipart-manifest=get'),
+                mock.call('test_c',
+                          'test_o',
+                          resp_chunk_size=65536,
+                          headers={'If-None-Match': on_disk_md5},
+                          response_dict={})])