Alchemy Scaffold Update

- Removed the need for a global session object
- Moved from the extension to the register method for hooking up the
  transaction manager
- Added the database session to the request object
- Set up a `BaseTest` class which is something the developer would end
  up doing anyways

5 files changed, 88 insertions, 59 deletions

diff --git a/pyramid/scaffolds/alchemy/+package+/__init__.py b/pyramid/scaffolds/alchemy/+package+/__init__.py
index 867049e4f..116839351 100644
--- a/pyramid/scaffolds/alchemy/+package+/__init__.py
+++ b/pyramid/scaffolds/alchemy/+package+/__init__.py
@@ -1,20 +1,11 @@
 from pyramid.config import Configurator
-from sqlalchemy import engine_from_config
-
-from .models import (
-    DBSession,
-    Base,
-    )
-
 
 def main(global_config, **settings):
     """ This function returns a Pyramid WSGI application.
     """
-    engine = engine_from_config(settings, 'sqlalchemy.')
-    DBSession.configure(bind=engine)
-    Base.metadata.bind = engine
     config = Configurator(settings=settings)
     config.include('pyramid_chameleon')
+    config.include('.models')
     config.add_static_view('static', 'static', cache_max_age=3600)
     config.add_route('home', '/')
     config.scan()
diff --git a/pyramid/scaffolds/alchemy/+package+/models.py b/pyramid/scaffolds/alchemy/+package+/models.py
index a0d3e7b71..ccf1f2379 100644
--- a/pyramid/scaffolds/alchemy/+package+/models.py
+++ b/pyramid/scaffolds/alchemy/+package+/models.py
@@ -5,17 +5,42 @@ from sqlalchemy import (
     Text,
     )
 
+from sqlalchemy import engine_from_config
 from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+import zope.sqlalchemy
 
-from sqlalchemy.orm import (
-    scoped_session,
-    sessionmaker,
+
+Base = declarative_base()
+
+
+def includeme(config):
+    settings = config.get_settings()
+    dbmaker = get_dbmaker(get_engine(settings))
+
+    config.add_request_method(
+        lambda r: get_session(r.tm, dbmaker),
+        'dbsession',
+        reify=True
     )
 
-from zope.sqlalchemy import ZopeTransactionExtension
+    config.include('pyramid_tm')
 
-DBSession = scoped_session(sessionmaker(extension=ZopeTransactionExtension()))
-Base = declarative_base()
+
+def get_session(transaction_manager, dbmaker):
+    dbsession = dbmaker()
+    zope.sqlalchemy.register(dbsession, transaction_manager=transaction_manager)
+    return dbsession
+
+
+def get_engine(settings, prefix='sqlalchemy.'):
+    return engine_from_config(settings, prefix)
+
+
+def get_dbmaker(engine):
+    dbmaker = sessionmaker()
+    dbmaker.configure(bind=engine)
+    return dbmaker
 
 
 class MyModel(Base):
@@ -24,4 +49,5 @@ class MyModel(Base):
     name = Column(Text)
     value = Column(Integer)
 
+
 Index('my_index', MyModel.name, unique=True, mysql_length=255)
diff --git a/pyramid/scaffolds/alchemy/+package+/scripts/initializedb.py b/pyramid/scaffolds/alchemy/+package+/scripts/initializedb.py
index 7dfdece15..43e25bff8 100644
--- a/pyramid/scaffolds/alchemy/+package+/scripts/initializedb.py
+++ b/pyramid/scaffolds/alchemy/+package+/scripts/initializedb.py
@@ -2,8 +2,6 @@ import os
 import sys
 import transaction
 
-from sqlalchemy import engine_from_config
-
 from pyramid.paster import (
     get_appsettings,
     setup_logging,
@@ -12,9 +10,11 @@ from pyramid.paster import (
 from pyramid.scripts.common import parse_vars
 
 from ..models import (
-    DBSession,
     MyModel,
     Base,
+    get_session,
+    get_engine,
+    get_dbmaker,
     )
 
 
@@ -32,9 +32,14 @@ def main(argv=sys.argv):
     options = parse_vars(argv[2:])
     setup_logging(config_uri)
     settings = get_appsettings(config_uri, options=options)
-    engine = engine_from_config(settings, 'sqlalchemy.')
-    DBSession.configure(bind=engine)
+
+    engine = get_engine(settings)
+    dbmaker = get_dbmaker(engine)
+
+    dbsession = get_session(transaction.manager, dbmaker)
+
     Base.metadata.create_all(engine)
+
     with transaction.manager:
         model = MyModel(name='one', value=1)
-        DBSession.add(model)
+        dbsession.add(model)
diff --git a/pyramid/scaffolds/alchemy/+package+/tests.py_tmpl b/pyramid/scaffolds/alchemy/+package+/tests.py_tmpl
index e6425eb91..4ce706077 100644
--- a/pyramid/scaffolds/alchemy/+package+/tests.py_tmpl
+++ b/pyramid/scaffolds/alchemy/+package+/tests.py_tmpl
@@ -3,53 +3,63 @@ import transaction
 
 from pyramid import testing
 
-from .models import DBSession
 
+def dummy_request(dbsession):
+    return testing.DummyRequest(dbsession=dbsession)
 
-class TestMyViewSuccessCondition(unittest.TestCase):
+
+class BaseTest(unittest.TestCase):
     def setUp(self):
-        self.config = testing.setUp()
-        from sqlalchemy import create_engine
-        engine = create_engine('sqlite://')
+        self.config = testing.setUp(settings={
+            'sqlalchemy.url': 'sqlite:///:memory:'
+        })
+        self.config.include('.models')
+        settings = self.config.get_settings()
+
         from .models import (
-            Base,
-            MyModel,
+            get_session,
+            get_engine,
+            get_dbmaker,
             )
-        DBSession.configure(bind=engine)
-        Base.metadata.create_all(engine)
-        with transaction.manager:
-            model = MyModel(name='one', value=55)
-            DBSession.add(model)
+
+        self.engine = get_engine(settings)
+        dbmaker = get_dbmaker(self.engine)
+
+        self.session = get_session(transaction.manager, dbmaker)
+
+    def init_database(self):
+        from .models import Base
+        Base.metadata.create_all(self.engine)
 
     def tearDown(self):
-        DBSession.remove()
+        from .models import Base
+
         testing.tearDown()
+        transaction.abort()
+        Base.metadata.create_all(self.engine)
+
+
+class TestMyViewSuccessCondition(BaseTest):
+
+    def setUp(self):
+        super(TestMyViewSuccessCondition, self).setUp()
+        self.init_database()
+
+        from .models import MyModel
+
+        model = MyModel(name='one', value=55)
+        self.session.add(model)
 
     def test_passing_view(self):
         from .views import my_view
-        request = testing.DummyRequest()
-        info = my_view(request)
+        info = my_view(dummy_request(self.session))
         self.assertEqual(info['one'].name, 'one')
         self.assertEqual(info['project'], '{{project}}')
 
 
-class TestMyViewFailureCondition(unittest.TestCase):
-    def setUp(self):
-        self.config = testing.setUp()
-        from sqlalchemy import create_engine
-        engine = create_engine('sqlite://')
-        from .models import (
-            Base,
-            MyModel,
-            )
-        DBSession.configure(bind=engine)
-
-    def tearDown(self):
-        DBSession.remove()
-        testing.tearDown()
+class TestMyViewFailureCondition(BaseTest):
 
     def test_failing_view(self):
         from .views import my_view
-        request = testing.DummyRequest()
-        info = my_view(request)
-        self.assertEqual(info.status_int, 500)
\ No newline at end of file
+        info = my_view(dummy_request(self.session))
+        self.assertEqual(info.status_int, 500)
diff --git a/pyramid/scaffolds/alchemy/+package+/views.py_tmpl b/pyramid/scaffolds/alchemy/+package+/views.py_tmpl
index 292bce579..b559b31ce 100644
--- a/pyramid/scaffolds/alchemy/+package+/views.py_tmpl
+++ b/pyramid/scaffolds/alchemy/+package+/views.py_tmpl
@@ -3,16 +3,13 @@ from pyramid.view import view_config
 
 from sqlalchemy.exc import DBAPIError
 
-from .models import (
-    DBSession,
-    MyModel,
-    )
+from .models import MyModel
 
 
 @view_config(route_name='home', renderer='templates/mytemplate.pt')
 def my_view(request):
     try:
-        one = DBSession.query(MyModel).filter(MyModel.name == 'one').first()
+        one = request.dbsession.query(MyModel).filter(MyModel.name == 'one').first()
     except DBAPIError:
         return Response(conn_err_msg, content_type='text/plain', status_int=500)
     return {'one': one, 'project': '{{project}}'}