- New features added to support engine/pool plugins with advanced

functionality.   Added a new "soft invalidate" feature to the
connection pool at the level of the checked out connection wrapper
as well as the :class:`._ConnectionRecord`.  This works similarly
to a modern pool invalidation in that connections aren't actively
closed, but are recycled only on next checkout; this is essentially
a per-connection version of that feature.  A new event
:class:`.PoolEvents.soft_invalidate` is added to complement it.
fixes #3379

- Added new flag
:attr:`.ExceptionContext.invalidate_pool_on_disconnect`.
Allows an error handler within :meth:`.ConnectionEvents.handle_error`
to maintain a "disconnect" condition, but to handle calling invalidate
on individual connections in a specific manner within the event.

- Added new event :class:`.DialectEvents.do_connect`, which allows
interception / replacement of when the :meth:`.Dialect.connect`
hook is called to create a DBAPI connection.  Also added
dialect plugin hooks :meth:`.Dialect.get_dialect_cls` and
:meth:`.Dialect.engine_created` which allow external plugins to
add events to existing dialects using entry points.
fixes #3355

1 files changed, 28 insertions, 1 deletions

diff --git a/test/engine/test_parseconnect.py b/test/engine/test_parseconnect.py
index 9f1b5ceba..fb1f338e6 100644
--- a/test/engine/test_parseconnect.py
+++ b/test/engine/test_parseconnect.py
@@ -5,7 +5,7 @@ from sqlalchemy.engine.default import DefaultDialect
 import sqlalchemy as tsa
 from sqlalchemy.testing import fixtures
 from sqlalchemy import testing
-from sqlalchemy.testing.mock import Mock, MagicMock
+from sqlalchemy.testing.mock import Mock, MagicMock, call
 from sqlalchemy import event
 from sqlalchemy import select
 
@@ -340,6 +340,33 @@ class TestRegNewDBAPI(fixtures.TestBase):
         e = create_engine("mysql+my_mock_dialect://")
         assert isinstance(e.dialect, MockDialect)
 
+    @testing.requires.sqlite
+    def test_wrapper_hooks(self):
+        def get_dialect_cls(url):
+            url.drivername = "sqlite"
+            return url.get_dialect()
+
+        global WrapperFactory
+        WrapperFactory = Mock()
+        WrapperFactory.get_dialect_cls.side_effect = get_dialect_cls
+
+        from sqlalchemy.dialects import registry
+        registry.register("wrapperdialect", __name__, "WrapperFactory")
+
+        from sqlalchemy.dialects import sqlite
+        e = create_engine("wrapperdialect://")
+
+        eq_(e.dialect.name, "sqlite")
+        assert isinstance(e.dialect, sqlite.dialect)
+
+        eq_(
+            WrapperFactory.mock_calls,
+            [
+                call.get_dialect_cls(url.make_url("sqlite://")),
+                call.engine_created(e)
+            ]
+        )
+
 
 class MockDialect(DefaultDialect):
     @classmethod