Implement database migrations (bug 1376479)

We're using Alembic with Flask-Alembic.
Added revision and upgrade manage.py commands.
Created a initialization migration.
Removed the schema file, `upgrade` is used to create the tables.
Use `invoke revision {name-of-revision}` to create a migration revision.

Author: zalun

README.md

@@ -15,10 +15,10 @@ our code management microservice ecosystem.
 
 ##### Running the development server
 
-To create a database schema:
+To create a database:
 
 ```bash
-$ invoke create_db
+$ invoke upgrade
 ```
 
 To build and start the development services' containers: 

docker-compose.yml

@@ -21,6 +21,7 @@ services:
       - DATABASE_URL=sqlite:////db/sqlite.db
     volumes:
       - ./.db/:/db/
+      - ./migrations/:/migrations/
   py3-linter:
     build:
       context: ./

docker/Dockerfile-prod

@@ -12,6 +12,8 @@ RUN apk --update --no-cache add \
 RUN mkdir /db
 RUN chown app:app /db
 
+COPY migrations /migrations
+
 COPY requirements.txt /requirements.txt
 RUN pip install --no-cache -r /requirements.txt
 

docker/db/schema.db

@@ -5,9 +5,10 @@
 
 import click
 import connexion
+
 from connexion.resolver import RestyResolver
 from landoapi.dockerflow import dockerflow
-from landoapi.models.storage import db
+from landoapi.models.storage import alembic, db
 
 
 def create_app(version_path):
@@ -22,9 +23,16 @@ def create_app(version_path):
         'SQLALCHEMY_DATABASE_URI', os.environ.get('DATABASE_URL', 'sqlite://')
     )
     flask_app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
+    flask_app.config['ALEMBIC'] = {'script_location': '/migrations/'}
 
     flask_app.register_blueprint(dockerflow)
+
+    # Initialize database
     db.init_app(flask_app)
+
+    # Intialize the alembic extension
+    alembic.init_app(app.app)
+
     return app
 
 

landoapi/app.py

@@ -3,18 +3,25 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 from landoapi.app import create_app
-from landoapi.models.storage import db
+from landoapi.models.storage import alembic
 
 from flask_script import Manager
 
 app = create_app('/version.json')
+
 manager = Manager(app.app)
 
 
 @manager.command
-def create_db():
-    """Creates SQLAlchemy database schema."""
-    return db.create_all()
+def revision(message):
+    """Generate a new migration revision."""
+    return alembic.revision(message)
+
+
+@manager.command
+def upgrade():
+    """Run all available migration upgrades."""
+    return alembic.upgrade()
 
 
 if __name__ == "__main__":

landoapi/manage.py

@@ -1,6 +1,8 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
+from flask_alembic import Alembic
 from flask_sqlalchemy import SQLAlchemy
 
 db = SQLAlchemy()
+alembic = Alembic()

landoapi/models/storage.py

@@ -0,0 +1,34 @@
+"""add landings
+
+Revision ID: ae9dd729e66c
+Revises:
+Create Date: 2017-06-20 17:13:22.173811
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision = 'ae9dd729e66c'
+down_revision = None
+branch_labels = ('default', )
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table(
+        'landings',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('request_id', sa.Integer(), nullable=True),
+        sa.Column('revision_id', sa.String(length=30), nullable=True),
+        sa.Column('status', sa.Integer(), nullable=True),
+        sa.PrimaryKeyConstraint('id'), sa.UniqueConstraint('request_id')
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_table('landings')
+    # ### end Alembic commands ###

migrations/ae9dd729e66c_add_landings.py

@@ -0,0 +1,24 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision = ${repr(up_revision)}
+down_revision = ${repr(down_revision)}
+branch_labels = ${repr(branch_labels)}
+depends_on = ${repr(depends_on)}
+
+
+def upgrade():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}

migrations/script.py.mako

@@ -57,3 +57,16 @@ Flask-SQLAlchemy==2.2 \
     --hash=sha256:fa3bd6343de231b2b3376a276df6d331c63c766449b660fc04d375a1c21312ac
 Flask-Script==2.0.5 \
     --hash=sha256:cef76eac751396355429a14c38967bb14d4973c53e07dec94af5cc8fb017107f
+alembic==0.9.2 \
+    --hash=sha256:a2b6b599f48b39ebf33b7dd069463924ca59c94aae7ae6f3661e0e54b5e78647
+Mako==1.0.6 \
+    --hash=sha256:48559ebd872a8e77f92005884b3d88ffae552812cdf17db6768e5c3be5ebbe0d
+python-editor==1.0.3 \
+    --hash=sha256:a3c066acee22a1c94f63938341d4fb374e3fdd69366ed6603d7b24bed1efc565
+python-dateutil==2.6.0 \
+    --hash=sha256:62a2f8df3d66f878373fd0072eacf4ee52194ba302e00082828e0d263b0418d2 \
+    --hash=sha256:3acbef017340600e9ff8f2994d8f7afd6eacb295383f286466a6df3961e486f0 \
+    --hash=sha256:537bf2a8f8ce6f6862ad705cd68f9e405c0b5db014aa40fa29eab4335d4b1716
+Flask-Alembic==2.0.1 \
+    --hash=sha256:05a1e6f4148dbfcc9280a393373bfbd250af6f9f4f0ca9f744ef8f7376a3deec \
+    --hash=sha256:7e67740b0b08d58dcae0c701d56b56e60f5fa4af907bb82b4cb0469229ba94ff

requirements.txt

@@ -71,7 +71,7 @@ def version(ctx):
     print(json.dumps(version))
 
 
-@task(name='build')
+@task
 def build(ctx):
     """Build the production docker image."""
     ctx.run(
@@ -89,12 +89,21 @@ def imageid(ctx):
     )
 
 
-@task(name='create_db')
-def create_db(ctx):
-    """Call `create_all` on a SQLAlchemy database."""
+@task
+def revision(ctx, msg):
+    """Call Alembic to create a migration revision"""
+    ctx.run(
+        "docker-compose run --rm lando-api "
+        "python landoapi/manage.py revision '%s'" % msg
+    )
+
+
+@task
+def upgrade(ctx):
+    """Call Alembic to run all available migration upgrades."""
     ctx.run(
         "docker-compose run --rm lando-api "
-        "python landoapi/manage.py create_db"
+        "python landoapi/manage.py upgrade"
     )
 
 
@@ -104,5 +113,5 @@ def create_db(ctx):
         lint_all,
         lint_flake8,
         lint_yapf,
-    ), build, create_db, format, imageid, test, version
+    ), build, format, imageid, revision, test, upgrade, version
 )