db: Add initial alembic configuration

No migrations yet: this is simply the output of 'alembic init' with some
minor tweaks.

Change-Id: Ib9423c2f751d7ec0a0dec89bdc39f9b6ab043655
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

.gitignore

@@ -71,3 +71,6 @@ etc/masakari/policy.yaml.sample
 doc/source/_static/masakari.conf.sample
 doc/source/_static/masakari-custom-recovery-methods.conf.sample
 doc/source/_static/masakari.policy.yaml.sample
+
+# Files created by alembic
+/masakari.db

masakari/db/sqlalchemy/alembic.ini

@@ -0,0 +1,40 @@
+[alembic]
+script_location = %(here)s/migrations
+prepend_sys_path = .
+version_path_separator = os
+sqlalchemy.url = sqlite:///masakari.db
+
+# 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

masakari/db/sqlalchemy/migrations/README.rst

@@ -0,0 +1,15 @@
+Database migrations
+===================
+
+This directory contains migrations for the database. These are implemented
+using `alembic`__, a lightweight database migration tool designed for usage
+with `SQLAlchemy`__.
+
+The best place to start understanding Alembic is with its own `tutorial`__. You
+can also play around with the :command:`alembic` command::
+
+    $ alembic --help
+
+.. __: https://alembic.sqlalchemy.org/en/latest/
+.. __: https://www.sqlalchemy.org/
+.. __: https://alembic.sqlalchemy.org/en/latest/tutorial.html

masakari/db/sqlalchemy/migrations/env.py

@@ -0,0 +1,85 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+
+# 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.
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+# from myapp import mymodel
+# target_metadata = mymodel.Base.metadata
+target_metadata = None
+
+
+def run_migrations_offline() -> None:
+    """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,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online() -> None:
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine
+    and associate a connection with the context.
+
+    """
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section, {}),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        context.configure(
+            connection=connection, target_metadata=target_metadata
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

masakari/db/sqlalchemy/migrations/script.py.mako

@@ -0,0 +1,32 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""${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() -> None:
+    ${upgrades if upgrades else "pass"}

requirements.txt

@@ -1,3 +1,4 @@
+alembic>=1.8.0 # MIT
 iso8601>=0.1.11 # MIT
 jsonschema>=3.2.0 # MIT
 keystoneauth1>=3.4.0 # Apache-2.0