Add SQLAlchemy and database boilerplate code

tofu_api/app.py

@@ -5,28 +5,58 @@ from flask import Flask
 
 from tofu_api.api import TofuApiBlueprint
 from tofu_api.config import DefaultConfig
+from tofu_api.dependencies import Dependencies
+
+
+class App(Flask):
+    """
+    Flask application for Tofu API.
+    """
+    # Dependencies container
+    dependencies: Dependencies
+
+    def __init__(self):
+        # Set instance path to the project root directory
+        project_root_dir = os.path.abspath('.')
+
+        # Create and configure the app
+        super().__init__(
+            'tofu_api',
+            instance_path=project_root_dir,
+            instance_relative_config=True,
+        )
+        self.config.from_object(DefaultConfig)
+
+        # Load app configuration from YAML file
+        self.config.from_file(os.getenv('FLASK_CONFIG_FILE', default='config.yml'), load=yaml.safe_load)
+
+        # Initialize DI container
+        self.dependencies = Dependencies()
+
+        # Initialize dependencies
+        self.init_database()
+
+        # Register blueprints
+        self.register_blueprint(TofuApiBlueprint(self))
+
+    def init_database(self) -> None:
+        """
+        Initialize database connection and models.
+        """
+        # Initialize SQLAlchemy, create the database engine based on the app config
+        db = self.dependencies.get_sqlalchemy()
+        db.init_database(self)
+
+        # Import models to fill the metadata object
+        import tofu_api.models  # noqa (unused import)
+
+        # Create all tables
+        # TODO: Use migrations instead
+        db.create_all_tables()
 
 
 def create_app() -> Flask:
     """
     App factory, returns a Flask app object.
     """
-    # Set instance path to the project root directory
-    project_root_dir = os.path.abspath('.')
-
-    # Create and configure the app
-    app = Flask(
-        'tofu_api',
-        instance_path=project_root_dir,
-        instance_relative_config=True,
-    )
-    app.config.from_object(DefaultConfig)
-
-    # Load app configuration from YAML file
-    app.config.from_file(os.getenv('FLASK_CONFIG_FILE', default='config.yml'), load=yaml.safe_load)
-
-    # Register blueprints
-    app.register_blueprint(TofuApiBlueprint())
-
-    # Return WSGI app
-    return app
+    return App()