Set up alembic migration usage (#954)

* Set up alembic migration usage

* Fix import order, add isort as alembic hook

* Only run migrations if needed

* Include date as part of migration file name for better sorting

* Skip initial migrations if tables already exist
This eases the transition from a pre-alembic state

* Fix deprecation warning in alembic revision

* Add alembic test stubs

mealie/db/init_db.py

@@ -1,7 +1,13 @@
+from pathlib import Path
+
+from sqlalchemy import engine
+
+from alembic import command, config, script
+from alembic.config import Config
+from alembic.runtime import migration
 from mealie.core import root_logger
 from mealie.core.config import get_app_settings
-from mealie.db.db_setup import create_session, engine
-from mealie.db.models._model_base import SqlAlchemyBase
+from mealie.db.db_setup import create_session
 from mealie.repos.all_repositories import get_repositories
 from mealie.repos.repository_factory import AllRepositories
 from mealie.repos.seed.init_users import default_user_init
@@ -9,15 +15,11 @@ from mealie.repos.seed.seeders import IngredientFoodsSeeder, IngredientUnitsSeed
 from mealie.schema.user.user import GroupBase
 from mealie.services.group_services.group_utils import create_new_group
 
+PROJECT_DIR = Path(__file__).parent.parent.parent
+
 logger = root_logger.get_logger("init_db")
 
 
-def create_all_models():
-    import mealie.db.models._all_models  # noqa: F401
-
-    SqlAlchemyBase.metadata.create_all(engine)
-
-
 def init_db(db: AllRepositories) -> None:
     # TODO: Port other seed data to use abstract seeder class
     default_group_init(db)
@@ -42,24 +44,33 @@ def default_group_init(db: AllRepositories):
     create_new_group(db, GroupBase(name=settings.DEFAULT_GROUP))
 
 
+# Adapted from https://alembic.sqlalchemy.org/en/latest/cookbook.html#test-current-database-revision-is-at-head-s
+def db_is_at_head(alembic_cfg: config.Config) -> bool:
+    settings = get_app_settings()
+    url = settings.DB_URL
+    connectable = engine.create_engine(url)
+    directory = script.ScriptDirectory.from_config(alembic_cfg)
+    with connectable.begin() as connection:
+        context = migration.MigrationContext.configure(connection)
+        return set(context.get_current_heads()) == set(directory.get_heads())
+
+
 def main():
-    create_all_models()
+    alembic_cfg = Config(str(PROJECT_DIR / "alembic.ini"))
+    if db_is_at_head(alembic_cfg):
+        logger.info("Migration not needed.")
+    else:
+        logger.info("Migration needed. Performing migration...")
+        command.upgrade(alembic_cfg, "head")
 
     session = create_session()
     db = get_repositories(session)
 
-    try:
-        init_user = db.users.get_all()
-        if not init_user:
-            raise Exception("No users found in database")
-    except Exception:
-        init_db(db)
-        return
-
+    init_user = db.users.get_all()
     if init_user:
-        logger.info("Database Exists")
+        logger.info("Database exists")
     else:
-        logger.info("Database Doesn't Exists, Initializing...")
+        logger.info("Database contains no users, initializing...")
         init_db(db)