handle SSL failures when fetching arbitrary URLs

fixes https://console.cloud.google.com/errors/CJOuzd2b1sehPA

common.py

@@ -79,7 +79,11 @@ def _requests_fn(fn, url, parse_json=False, **kwargs):
     """Wraps requests.* and adds raise_for_status() and User-Agent."""
     kwargs.setdefault('headers', {}).update(HEADERS)
 
-    resp = fn(url, **kwargs)
+    try:
+        resp = fn(url, **kwargs)
+    except (requests.ConnectionError, requests.Timeout) as e:
+        logging.warning(url, exc_info=True)
+        raise exc.HTTPBadGateway(unicode(e))
 
     logging.info('Got %s headers:%s', resp.status_code, resp.headers)
     type = content_type(resp)

tests/test_common.py

@@ -58,3 +58,9 @@ class CommonTest(testutil.TestCase):
     def test_get_as2_not_acceptable(self, mock_get):
         with self.assertRaises(exc.HTTPBadGateway):
             resp = common.get_as2('http://orig')
+
+    @mock.patch('requests.get', side_effect=requests.exceptions.SSLError)
+    def test_get_ssl_error(self, mock_get):
+        with self.assertRaises(exc.HTTPBadGateway):
+            resp = common.get_as2('http://orig')
+