Accommodate immutable URL api

SQLAlchemy 1.4 has modified the URL object to be immutable.
This patch makes the adjustments needed, using duck-typing
to check if the URL object is of the new style.  When
requirements reach SQLAlchemy 1.4 as the minimum required
version, these conditionals should be removed in favor of
the noted option in each.

Change-Id: Id2f0663b13ed0f81e91a8d44f73d8541015bf844

4 files changed, 46 insertions, 9 deletions

diff --git a/oslo_db/sqlalchemy/engines.py b/oslo_db/sqlalchemy/engines.py
index 25215b9..0e19c18 100644
--- a/oslo_db/sqlalchemy/engines.py
+++ b/oslo_db/sqlalchemy/engines.py
@@ -105,6 +105,14 @@ def _setup_logging(connection_debug=0):
 
 
 def _extend_url_parameters(url, connection_parameters):
+    # TODO(zzzeek): remove hasattr() conditional when SQLAlchemy 1.4 is the
+    # minimum version in requirements; call update_query_string()
+    # unconditionally
+    if hasattr(url, "update_query_string"):
+        return url.update_query_string(connection_parameters, append=True)
+
+    # TODO(zzzeek): remove the remainder of this method when SQLAlchemy 1.4
+    # is the minimum version in requirements
     for key, value in parse.parse_qs(
             connection_parameters).items():
         if key in url.query:
@@ -118,6 +126,8 @@ def _extend_url_parameters(url, connection_parameters):
         if len(value) == 1:
             url.query[key] = value[0]
 
+    return url
+
 
 def _vet_url(url):
     if "+" not in url.drivername and not url.drivername.startswith("sqlite"):
@@ -153,7 +163,7 @@ def create_engine(sql_connection, sqlite_fk=False, mysql_sql_mode=None,
     url = sqlalchemy.engine.url.make_url(sql_connection)
 
     if connection_parameters:
-        _extend_url_parameters(url, connection_parameters)
+        url = _extend_url_parameters(url, connection_parameters)
 
     _vet_url(url)
 
diff --git a/oslo_db/sqlalchemy/provision.py b/oslo_db/sqlalchemy/provision.py
index 2fc3a54..5addab4 100644
--- a/oslo_db/sqlalchemy/provision.py
+++ b/oslo_db/sqlalchemy/provision.py
@@ -495,7 +495,16 @@ class BackendImpl(object, metaclass=abc.ABCMeta):
         """
 
         url = sa_url.make_url(str(base_url))
-        url.database = ident
+
+        # TODO(zzzeek): remove hasattr() conditional in favor of "url.set()"
+        # when SQLAlchemy 1.4 is the minimum version in requirements
+        if hasattr(url, "set"):
+            url = url.set(database=ident)
+        else:
+            # TODO(zzzeek): remove when SQLAlchemy 1.4
+            # is the minimum version in requirements
+            url.database = ident
+
         return url
 
 
diff --git a/oslo_db/tests/sqlalchemy/test_exc_filters.py b/oslo_db/tests/sqlalchemy/test_exc_filters.py
index 0451c89..7d55bb7 100644
--- a/oslo_db/tests/sqlalchemy/test_exc_filters.py
+++ b/oslo_db/tests/sqlalchemy/test_exc_filters.py
@@ -386,8 +386,16 @@ class TestNonExistentDatabase(
         super(TestNonExistentDatabase, self).setUp()
 
         url = sqla_url.make_url(str(self.engine.url))
-        url.database = 'non_existent_database'
-        self.url = url
+
+        # TODO(zzzeek): remove hasattr() conditional in favor of "url.set()"
+        # when SQLAlchemy 1.4 is the minimum version in requirements
+        if hasattr(url, "set"):
+            self.url = url.set(database="non_existent_database")
+        else:
+            # TODO(zzzeek): remove when SQLAlchemy 1.4
+            # is the minimum version in requirements
+            url.database = 'non_existent_database'
+            self.url = url
 
     def test_raise(self):
         matched = self.assertRaises(
diff --git a/oslo_db/tests/sqlalchemy/test_sqlalchemy.py b/oslo_db/tests/sqlalchemy/test_sqlalchemy.py
index 080f418..44b7453 100644
--- a/oslo_db/tests/sqlalchemy/test_sqlalchemy.py
+++ b/oslo_db/tests/sqlalchemy/test_sqlalchemy.py
@@ -229,6 +229,16 @@ class QueryParamTest(test_base.DbTestCase):
             "oslo_db.sqlalchemy.engines.sqlalchemy.create_engine",
             side_effect=_mock_create_engine)
 
+    def _normalize_query_dict(self, qdict):
+        # SQLAlchemy 1.4 returns url.query as:
+        # immutabledict({k1: v1, k2: (v2a, v2b, ...), ...})
+        # that is with tuples not lists for multiparams
+
+        return {
+            k: list(v) if isinstance(v, tuple) else v
+            for k, v in qdict.items()
+        }
+
     def test_add_assorted_params(self):
         with self._fixture() as ce:
             engines.create_engine(
@@ -236,7 +246,7 @@ class QueryParamTest(test_base.DbTestCase):
                 connection_parameters="foo=bar&bat=hoho&bat=param2")
 
         self.assertEqual(
-            ce.mock_calls[0][1][0].query,
+            self._normalize_query_dict(ce.mock_calls[0][1][0].query),
             {'bat': ['hoho', 'param2'], 'foo': 'bar'}
         )
 
@@ -247,7 +257,7 @@ class QueryParamTest(test_base.DbTestCase):
 
         self.assertEqual(
             ce.mock_calls[0][1][0].query,
-            {}
+            self._normalize_query_dict({})
         )
 
     def test_combine_params(self):
@@ -260,7 +270,7 @@ class QueryParamTest(test_base.DbTestCase):
                                       "bind_host=192.168.1.5")
 
         self.assertEqual(
-            ce.mock_calls[0][1][0].query,
+            self._normalize_query_dict(ce.mock_calls[0][1][0].query),
             {
                 'bind_host': '192.168.1.5',
                 'charset': 'utf8',
@@ -280,7 +290,7 @@ class QueryParamTest(test_base.DbTestCase):
                                       "bind_host=192.168.1.5")
 
         self.assertEqual(
-            ce.mock_calls[0][1][0].query,
+            self._normalize_query_dict(ce.mock_calls[0][1][0].query),
             {
                 'bind_host': '192.168.1.5',
                 'charset': 'utf8',
@@ -751,7 +761,7 @@ class CreateEngineTest(oslo_test.BaseTestCase):
         def warn_interpolate(msg, args):
             # test the interpolation itself to ensure the password
             # is concealed
-            warnings.warning(msg % args)
+            warnings.warning(msg % (args, ))
 
         with mock.patch(
                 "oslo_db.sqlalchemy.engines.LOG.warning",