Include transaction ID in ClientException.__str__

It's fairly annoying getting a traceback in swift's probe tests then
only having a URL and status code to go searching for in logs.

Leave the shell.py output untouched, though, since we output the
transaction ID on a new line anyway.

Change-Id: Idb849848ec08b6c04812b088467c9a687c2a7e27

swiftclient/exceptions.py

@@ -35,6 +35,13 @@ class ClientException(Exception):
         self.http_response_content = http_response_content
         self.http_response_headers = http_response_headers
 
+        self.transaction_id = None
+        if self.http_response_headers:
+            for header in ('X-Trans-Id', 'X-Openstack-Request-Id'):
+                if header in self.http_response_headers:
+                    self.transaction_id = self.http_response_headers[header]
+                    break
+
     @classmethod
     def from_response(cls, resp, msg=None, body=None):
         msg = msg or '%s %s' % (resp.status_code, resp.reason)
@@ -78,4 +85,7 @@ class ClientException(Exception):
             else:
                 b += '  [first 60 chars of response] %s' \
                     % self.http_response_content[:60]
-        return b and '%s: %s' % (a, b) or a
+        c = ''
+        if self.transaction_id:
+            c = ' (txn: %s)' % self.transaction_id
+        return b and '%s: %s%s' % (a, b, c) or (a + c)

swiftclient/shell.py

@@ -2058,8 +2058,9 @@ Examples:
         try:
             globals()['st_%s' % args[0]](parser, argv[1:], output)
         except ClientException as err:
+            trans_id = err.transaction_id
+            err.transaction_id = None  # clear it so we aren't overly noisy
             output.error(str(err))
-            trans_id = (err.http_response_headers or {}).get('X-Trans-Id')
             if trans_id:
                 output.error("Failed Transaction ID: %s",
                              parse_header_string(trans_id))

test/unit/test_swiftclient.py

@@ -84,6 +84,23 @@ class TestClientException(unittest.TestCase):
             self.assertIs(True, hasattr(exc, key))
             self.assertEqual(getattr(exc, key), value)
 
+    def test_transaction_id_from_headers(self):
+        exc = c.ClientException('test')
+        self.assertIsNone(exc.transaction_id)
+
+        exc = c.ClientException('test', http_response_headers={})
+        self.assertIsNone(exc.transaction_id)
+
+        exc = c.ClientException('test', http_response_headers={
+            'X-Trans-Id': 'some-id'})
+        self.assertEqual(exc.transaction_id, 'some-id')
+        self.assertIn('(txn: some-id)', str(exc))
+
+        exc = c.ClientException('test', http_response_headers={
+            'X-Openstack-Request-Id': 'some-other-id'})
+        self.assertEqual(exc.transaction_id, 'some-other-id')
+        self.assertIn('(txn: some-other-id)', str(exc))
+
 
 class MockHttpResponse(object):
     def __init__(self, status=0, headers=None, verify=False):