Implement custom config class; get SQLAlchemy database URI from config

config.dev.yml

@@ -1 +1,6 @@
+# Secret key (CHANGE TO RANDOM STRING IN PRODUCTION!)
 SECRET_KEY: 'development'
+
+# Database configuration
+SQLALCHEMY_DATABASE_URI: 'sqlite:////tmp/test.db'
+SQLALCHEMY_ECHO: false

tofu_api/app.py

@@ -1,10 +1,9 @@
 import os
 
-import yaml
 from flask import Flask
 
 from tofu_api.api import TofuApiBlueprint
-from tofu_api.config import DefaultConfig
+from tofu_api.common.config import Config
 from tofu_api.dependencies import Dependencies
 
 
@@ -12,6 +11,12 @@ class App(Flask):
     """
     Flask application for Tofu API.
     """
+    # Override Flask classes
+    config_class = Config
+
+    # Set type hint for config
+    config: Config
+
     # Dependencies container
     dependencies: Dependencies
 
@@ -25,10 +30,9 @@ class App(Flask):
             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)
+        self.config.from_yaml(os.getenv('FLASK_CONFIG_FILE', default='config.yml'))
 
         # Initialize DI container
         self.dependencies = Dependencies()

tofu_api/common/config/__init__.py

@@ -0,0 +1,2 @@
+from .config import Config
+from .defaults import DefaultConfig

tofu_api/common/config/config.py

@@ -0,0 +1,32 @@
+import yaml
+from flask import Config as BaseConfig
+
+from .defaults import DefaultConfig
+
+
+class Config(BaseConfig):
+    """
+    Custom config class for the Flask application.
+    """
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        # Set app-specific default values
+        self.from_object(DefaultConfig)
+
+    def from_yaml(self, filename: str, *, silent: bool = False) -> bool:
+        """
+        Update config from a YAML file.
+        """
+        return self.from_file(filename, load=yaml.safe_load, silent=silent)
+
+    # Properties for type safe access to config values
+
+    @property
+    def sqlalchemy_database_uri(self) -> str:
+        return self.get('SQLALCHEMY_DATABASE_URI')
+
+    @property
+    def sqlalchemy_echo(self) -> bool:
+        return bool(self.get('SQLALCHEMY_ECHO'))

tofu_api/common/config/defaults.py

@@ -0,0 +1,13 @@
+__all__ = [
+    'DefaultConfig',
+]
+
+
+class DefaultConfig:
+    """
+    This class defines default values for the app configuration.
+    """
+
+    # Database configuration
+    SQLALCHEMY_DATABASE_URI = None
+    SQLALCHEMY_ECHO = False

tofu_api/common/database/sqlalchemy.py

@@ -5,6 +5,7 @@ from sqlalchemy import MetaData, create_engine
 from sqlalchemy.engine import Engine
 from sqlalchemy.orm import Session, scoped_session, sessionmaker
 
+from tofu_api.common.config import Config
 from .metadata import metadata_obj
 
 __all__ = [
@@ -23,19 +24,22 @@ class SQLAlchemy:
         """
         Initializes the SQLAlchemy engine.
         """
-        self._engine = self._create_engine()
+        self._engine = self._create_engine(app.config)
         self._scoped_session = self._create_scoped_session()
 
         @app.teardown_appcontext
         def shutdown_session(_exception=None):
             self._scoped_session.remove()
 
-    def _create_engine(self) -> Engine:
+    @staticmethod
+    def _create_engine(config: Config) -> Engine:
         """
         Create the database engine using the app configuration.
         """
-        # TODO: Use config
-        return create_engine('sqlite:////tmp/test.db')
+        return create_engine(
+            config.sqlalchemy_database_uri,
+            echo=config.sqlalchemy_echo,
+        )
 
     def _create_scoped_session(self) -> scoped_session:
         """

tofu_api/config.py

@@ -1,5 +0,0 @@
-class DefaultConfig:
-    """
-    This class defined default values for the app configuration.
-    """
-    # TODO