Include transaction ID on content-check failures

Change-Id: I6b667db26ffc5dccdcadfc8c73f7accb81f03dac

2 files changed, 27 insertions, 9 deletions

diff --git a/swiftclient/service.py b/swiftclient/service.py
index d1c98d6..e905ea6 100644
--- a/swiftclient/service.py
+++ b/swiftclient/service.py
@@ -419,6 +419,9 @@ class _SwiftReader:
     def __init__(self, path, body, headers, checksum=True):
         self._path = path
         self._body = body
+        self._txn_id = headers.get('x-openstack-request-id')
+        if self._txn_id is None:
+            self._txn_id = headers.get('x-trans-id')
         self._actual_read = 0
         self._content_length = None
         self._actual_md5 = None
@@ -459,17 +462,20 @@ class _SwiftReader:
     def _check_contents(self):
         if (self._content_length is not None and
                 self._actual_read != self._content_length):
-            raise SwiftError('Error downloading {0}: read_length != '
-                             'content_length, {1:d} != {2:d}'.format(
-                                 self._path, self._actual_read,
-                                 self._content_length))
+            raise SwiftError(
+                'Error downloading {0}: read_length != content_length, '
+                '{1:d} != {2:d} (txn: {3})'.format(
+                    self._path, self._actual_read, self._content_length,
+                    self._txn_id or 'unknown'))
 
         if self._actual_md5 and self._expected_md5:
             etag = self._actual_md5.hexdigest()
             if etag != self._expected_md5:
-                raise SwiftError('Error downloading {0}: md5sum != etag, '
-                                 '{1} != {2}'.format(
-                                     self._path, etag, self._expected_md5))
+                raise SwiftError(
+                    'Error downloading {0}: md5sum != etag, '
+                    '{1} != {2} (txn: {3})'.format(
+                        self._path, etag, self._expected_md5,
+                        self._txn_id or 'unknown'))
 
     def bytes_read(self):
         return self._actual_read
diff --git a/test/unit/test_service.py b/test/unit/test_service.py
index b6db22d..cdab61f 100644
--- a/test/unit/test_service.py
+++ b/test/unit/test_service.py
@@ -201,7 +201,19 @@ class TestSwiftReader(unittest.TestCase):
         with self.assertRaises(SwiftError) as cm:
             _consume(sr)
         self.assertEqual(
-            "'Error downloading path: read_length != content_length, 4 != 5'",
+            "'Error downloading path: read_length != content_length, "
+            "4 != 5 (txn: unknown)'",
+            str(cm.exception))
+
+        # Check error includes txn id if available
+        sr = self.sr('path', BytesIO(b'body'), {'content-length': 5,
+                                                'etag': 'bad etag',
+                                                'x-trans-id': 'uuid'})
+        with self.assertRaises(SwiftError) as cm:
+            _consume(sr)
+        self.assertEqual(
+            "'Error downloading path: read_length != content_length, "
+            "4 != 5 (txn: uuid)'",
             str(cm.exception))
 
         # Check error is raised if SwiftReader doesn't calculate the expected
@@ -212,7 +224,7 @@ class TestSwiftReader(unittest.TestCase):
             _consume(sr)
         self.assertEqual(
             "'Error downloading path: md5sum != etag, "
-            "841a2d689ad86bd1611447453c22c6fc != bad etag'",
+            "841a2d689ad86bd1611447453c22c6fc != bad etag (txn: unknown)'",
             str(cm.exception))
 
         sr = self.sr('path', BytesIO(b'body'), {'content-length': 4})