Add Flask-Migrate support

Add Flask-Migrate to manage database schema changes

Author: armooo

README.md

@@ -30,7 +30,7 @@ development machine so that it pretends to be
 
 4. Create the database tables:
 
-        $ python manage.py create_tables
+        $ python manage.py db upgrade
 
 5. Start the server:
 

manage.py

@@ -1,12 +1,11 @@
+from flask.ext.migrate import MigrateCommand
 from flask.ext.script import Manager
-from studygroup.application import create_app, db
 
+from studygroup.application import create_app
 
 manager = Manager(create_app)
+manager.add_command('db', MigrateCommand)
 
-@manager.command
-def create_tables():
-    db.create_all()
 
 if __name__ == "__main__":
     manager.run()

migrations/README

@@ -0,0 +1 @@
+Generic single-database configuration.

migrations/alembic.ini

@@ -0,0 +1,45 @@
+# A generic, single database configuration.
+
+[alembic]
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S

migrations/env.py

@@ -0,0 +1,73 @@
+from __future__ import with_statement
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+from logging.config import fileConfig
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+fileConfig(config.config_file_name)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+from flask import current_app
+config.set_main_option('sqlalchemy.url', current_app.config.get('SQLALCHEMY_DATABASE_URI'))
+target_metadata = current_app.extensions['migrate'].db.metadata
+
+# other values from the config, defined by the needs of env.py,
+# can be acquired:
+# my_important_option = config.get_main_option("my_important_option")
+# ... etc.
+
+def run_migrations_offline():
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(url=url)
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+def run_migrations_online():
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine
+    and associate a connection with the context.
+
+    """
+    engine = engine_from_config(
+                config.get_section(config.config_ini_section),
+                prefix='sqlalchemy.',
+                poolclass=pool.NullPool)
+
+    connection = engine.connect()
+    context.configure(
+                connection=connection,
+                target_metadata=target_metadata
+                )
+
+    try:
+        with context.begin_transaction():
+            context.run_migrations()
+    finally:
+        connection.close()
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()
+

migrations/script.py.mako

@@ -0,0 +1,22 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision}
+Create Date: ${create_date}
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = ${repr(up_revision)}
+down_revision = ${repr(down_revision)}
+
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+def upgrade():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

migrations/versions/9975799c2b8_.py

@@ -0,0 +1,52 @@
+"""Initial schema
+
+Revision ID: 9975799c2b8
+Revises: None
+Create Date: 2014-04-17 21:20:28.470577
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '9975799c2b8'
+down_revision = None
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('user',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('meetup_member_id', sa.String(), nullable=True),
+    sa.Column('full_name', sa.String(), nullable=True),
+    sa.Column('is_admin', sa.Boolean(), nullable=False),
+    sa.PrimaryKeyConstraint('id'),
+    sa.UniqueConstraint('meetup_member_id')
+    )
+    op.create_table('group',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('name', sa.String(), nullable=True),
+    sa.Column('description', sa.String(), nullable=True),
+    sa.Column('max_members', sa.Integer(), nullable=False),
+    sa.PrimaryKeyConstraint('id'),
+    sa.UniqueConstraint('name')
+    )
+    op.create_table('membership',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('user_id', sa.Integer(), nullable=True),
+    sa.Column('group_id', sa.Integer(), nullable=True),
+    sa.Column('role', sa.Integer(), nullable=False),
+    sa.ForeignKeyConstraint(['group_id'], ['group.id'], ),
+    sa.ForeignKeyConstraint(['user_id'], ['user.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    ### end Alembic commands ###
+
+
+def downgrade():
+    ### commands auto generated by Alembic - please adjust! ###
+    op.drop_table('membership')
+    op.drop_table('group')
+    op.drop_table('user')
+    ### end Alembic commands ###

requirements.txt

@@ -1,14 +1,17 @@
-Flask==0.10.1
 Flask-Bootstrap==3.1.0.1
+Flask-Migrate==1.2.0
 Flask-OAuthlib==0.4.2
 Flask-SQLAlchemy==1.0
 Flask-Script==0.6.6
 Flask-WTF==0.9.4
+Flask==0.10.1
 Jinja2==2.7.2
+Mako==0.9.1
 MarkupSafe==0.18
 SQLAlchemy==0.9.1
 WTForms==1.0.5
 Werkzeug==0.9.4
+alembic==0.6.4
 itsdangerous==0.23
 oauthlib==0.6.1
 psycopg2==2.5.2

studygroup/application.py

@@ -1,13 +1,15 @@
 from flask import Flask
 from flask_oauthlib.client import OAuth
 from flask_bootstrap import Bootstrap
+from flask.ext.migrate import Migrate
 from flask.ext.sqlalchemy import SQLAlchemy
 
 import settings
 
 
 db = SQLAlchemy()
 oauth = OAuth()
+migrate = Migrate()
 
 def create_app(debug=True):
     from views import studygroup
@@ -22,6 +24,7 @@ def create_app(debug=True):
     Bootstrap(app)
     db.init_app(app)
     oauth.init_app(app)
+    migrate.init_app(app, db)
 
     return app
 

tests/test_app.py

@@ -16,7 +16,7 @@ def test_logged_in(self):
         self.login(self.alice_id)
         resp = self.client.get('/')
         self.assert200(resp)
-        self.assertIn('Welcome, Alice B. Admin', resp.data)
+        self.assertIn('Welcome, Alice B.', resp.data)
         self.assertNotIn('Sign In Now', resp.data)
 
 

tests/tools.py

@@ -2,24 +2,29 @@
 Tools to help test StudyGroup.
 """
 
-import unittest
+import os.path
 
-from flask import session
+import flask.ext.migrate
 from flask.ext.testing import TestCase
 
 from studygroup.application import create_app, db
 from studygroup.models import User
 
 
+DB_PATH = 'sqlite:///' + os.path.dirname(__file__) + '/../test.db'
+
+
 class StudyGroupTestCase(TestCase):
     """
     Base class for all StudyGroup tests.
     """
     def setUp(self):
-        db.create_all()
-        self.alice_id = self.create_user(full_name="Alice B. Admin")
+        flask.ext.migrate.upgrade()
+        self.alice_id = self.create_user(full_name='Alice B.')
+        self.admin_id = self.create_user(full_name='Bob Admin', is_admin=True)
 
     def tearDown(self):
+        db.session.execute('DROP TABLE alembic_version')
         db.session.remove()
         db.drop_all()
 
@@ -30,15 +35,19 @@ def create_app(self):
         app = create_app()
         app.config['TESTING'] = True
         app.config['WTF_CSRF_ENABLED'] = False
-        # Use an in-memory SQLite db.
-        app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite://'
+        # Use a SQLite db. Migrations will not work on an in-memory db.
+        app.config['SQLALCHEMY_DATABASE_URI'] = DB_PATH
+        app.config['SQLALCHEMY_POOL_SIZE'] = None
         return app
 
     def create_user(self, **kwargs):
         """
         Make a new user, and return the user id.
         """
         user = User(**kwargs)
+        import sqlalchemy.schema
+        metadata = sqlalchemy.schema.MetaData()
+        metadata.reflect(db.session.bind)
         db.session.add(user)
         db.session.commit()
         return user.id