Squashed commit of the following:

commit 1f625325a6993fe1d4d1d50b89912ff03c02b181
Author: Viktor Roytman <vr2262@columbia.edu>
Date:   Mon Dec 19 14:54:05 2016 -0500

    Update version to 0.1.2

commit 094d8c44e242a1da0c0127340bba97577243b361
Author: Viktor Roytman <vr2262@columbia.edu>
Date:   Mon Dec 19 14:53:15 2016 -0500

    Use session_scope recipe from SQLAlchemy docs

dev/commands.py

@@ -23,8 +23,8 @@ def create_user(*, email):
     """Create a user with the given e-mail."""
     from minigrid import models
     session = createdb(ensure=False)
-    with session.begin_nested():
-        session.add(models.User(email=email))
+    with models.transaction(session) as tx_session:
+        tx_session.add(models.User(email=email))
     print('Created user with e-mail ' + email)
 
 

minigrid/handlers.py

@@ -19,7 +19,9 @@ class BaseHandler(tornado.web.RequestHandler):
 
     @property
     def session(self):
-        """The db session. Use session.begin_nested() for transactions."""
+        """The database session.
+
+        Use the models.transaction(session) context manager."""
         return self.application.session
 
     def get_current_user(self):
@@ -89,8 +91,8 @@ def post(self):
         email = self.get_argument('email')
         reason = None
         try:
-            with self.session.begin_nested():
-                self.session.add(models.User(email=email))
+            with models.transaction(self.session) as session:
+                session.add(models.User(email=email))
         except IntegrityError as error:
             if 'user_email_check' in error.orig.pgerror:
                 reason = '{} is not a valid e-mail address'.format(email)

minigrid/models.py

@@ -1,4 +1,6 @@
 """ORM models."""
+from contextlib import contextmanager
+
 import sqlalchemy as sa
 from sqlalchemy.dialects import postgresql as pg
 from sqlalchemy.ext.declarative import declarative_base
@@ -31,6 +33,21 @@ def create_engine():
     return sa.create_engine(connection_string)
 
 
+@contextmanager
+def transaction(session):
+    """Provide a transactional scope around a series of operations.
+
+    Taken from http://docs.sqlalchemy.org/en/latest/orm/session_basics.html
+    #when-do-i-construct-a-session-when-do-i-commit-it-and-when-do-i-close-it
+    """
+    try:
+        yield session
+        session.commit()
+    except:
+        session.rollback()
+        raise
+
+
 def pk():
     """Return a primary key UUID column."""
     return sa.Column(

prod/create_initial_user.py

@@ -34,8 +34,8 @@ def main():
     if users:
         print('At least one user already exists. Log in as that user.')
         sys.exit(1)
-    with session.begin_nested():
-        session.add(models.User(email=args.email))
+    with models.transaction(session) as tx_session:
+        tx_session.add(models.User(email=args.email))
     print('Created initial user with e-mail', args.email)
 
 

prod/docker-compose.yml

@@ -1,7 +1,7 @@
 version: '2'
 services:
   minigrid:
-    image: selcolumbia/minigrid-server:0.1.1
+    image: selcolumbia/minigrid-server:0.1.2
     command: ./prod/run.sh --db_host=db --redis_url=redis://redis:6379/0 --minigrid-website-url=https://www.example.com
     depends_on:
       - redis

prod/install.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env sh
-# Minigrid Server installer for version 0.1.1
+# Minigrid Server installer for version 0.1.2
 set -e
 
 # Do you have docker installed?
@@ -108,8 +108,8 @@ $SUDO openssl dhparam -out /etc/letsencrypt/live/$LETSENCRYPT_DIR/dhparam.pem 20
 printf "========================================\n"
 printf " Generating configuration               \n"
 printf "========================================\n"
-$CURL -L https://raw.githubusercontent.com/SEL-Columbia/minigrid-server/0.1.1/prod/docker-compose.yml > docker-compose.yml
-$CURL -L https://raw.githubusercontent.com/SEL-Columbia/minigrid-server/0.1.1/prod/nginx.conf > nginx.conf
+$CURL -L https://raw.githubusercontent.com/SEL-Columbia/minigrid-server/0.1.2/prod/docker-compose.yml > docker-compose.yml
+$CURL -L https://raw.githubusercontent.com/SEL-Columbia/minigrid-server/0.1.2/prod/nginx.conf > nginx.conf
 
 sed -i s/www.example.com/$LETSENCRYPT_DIR/g docker-compose.yml
 sed -i s/www.example.com/$LETSENCRYPT_DIR/g nginx.conf

tests/python/test_handlers.py

@@ -20,14 +20,14 @@ def BeautifulSoup(page):
 class TestIndex(HTTPTest):
     def setUp(self):
         super().setUp()
-        with self.session.begin_nested():
+        with models.transaction(self.session) as session:
             self.user = models.User(email='a@a.com')
-            self.session.add(self.user)
+            session.add(self.user)
             self.minigrids = (
                 models.Minigrid(name='a', day_tariff=1, night_tariff=2),
                 models.Minigrid(name='b', day_tariff=10, night_tariff=20),
             )
-            self.session.add_all(self.minigrids)
+            session.add_all(self.minigrids)
 
     def test_get_not_logged_in(self):
         response = self.fetch('/')
@@ -56,14 +56,14 @@ def test_get_logged_in(self, get_current_user):
 class TestMinigridView(HTTPTest):
     def setUp(self):
         super().setUp()
-        with self.session.begin_nested():
+        with models.transaction(self.session) as session:
             self.user = models.User(email='a@a.com')
-            self.session.add(self.user)
+            session.add(self.user)
             self.minigrids = (
                 models.Minigrid(name='a', day_tariff=1, night_tariff=2),
                 models.Minigrid(name='b', day_tariff=10, night_tariff=20),
             )
-            self.session.add_all(self.minigrids)
+            session.add_all(self.minigrids)
 
     def test_get_not_logged_in(self):
         response = self.fetch(
@@ -99,12 +99,12 @@ def test_get_success(self, get_current_user):
 class TestUsersView(HTTPTest):
     def setUp(self):
         super().setUp()
-        with self.session.begin_nested():
+        with models.transaction(self.session) as session:
             self.users = (
                 models.User(email='a@a.com'),
                 models.User(email='b@b.com'),
             )
-            self.session.add_all(self.users)
+            session.add_all(self.users)
 
     def test_get_not_logged_in(self):
         response = self.fetch('/users', follow_redirects=False)
@@ -179,8 +179,8 @@ def test_verify_no_xsrf(self):
 
 class TestAuthentication(HTTPTest):
     def create_user(self, email='a@a.com'):
-        with self.session.begin_nested():
-            self.session.add(models.User(email=email))
+        with models.transaction(self.session) as session:
+            session.add(models.User(email=email))
 
     def test_login_missing_email(self):
         log_1 = ExpectLog('tornado.general', '.*Missing argument email')

tests/python/test_models.py

@@ -5,7 +5,7 @@
 
 class TestUser(Test):
     def test_create(self):
-        with self.session.begin_nested():
-            self.session.add(models.User(email='a@b.com'))
+        with models.transaction(self.session) as session:
+            session.add(models.User(email='a@b.com'))
         user = self.session.query(models.User).one()
         self.assertEqual(user.email, 'a@b.com')

tests/python/util.py

@@ -7,6 +7,7 @@
 
 import fakeredis
 
+from sqlalchemy import event
 from sqlalchemy.orm import sessionmaker
 
 from tornado.testing import AsyncHTTPTestCase
@@ -43,6 +44,20 @@ def setUp(self):
         self.connection = engine.connect()
         self.transaction = self.connection.begin()
         self.session = Session(bind=self.connection)
+        self.session.begin_nested()
+
+        @event.listens_for(self.session, 'after_transaction_end')
+        def restart_savepoint(session, transaction):
+            """Taken from
+
+            http://docs.sqlalchemy.org/en/latest/orm/session_transaction.html
+            #joining-a-session-into-an-external-transaction
+            -such-as-for-test-suites
+            """
+            if transaction.nested and not transaction._parent.nested:
+                session.expire_all()
+                session.begin_nested()
+
         super().setUp()
 
     def tearDown(self):