added support for home assistant postgres database and convenience function to get state of entity

utils/database/get_db_session.py

@@ -0,0 +1,61 @@
+"""Database connection utilities for Home Assistant PostgreSQL database."""
+
+import os
+from functools import lru_cache
+
+from dotenv import load_dotenv
+from sqlalchemy import create_engine, text
+from sqlalchemy.orm import sessionmaker
+
+# Load environment variables from .env file
+load_dotenv()
+
+
+@lru_cache(maxsize=1)
+def _get_engine(echo: bool = False):
+    """Create and cache the database engine (singleton)."""
+    required_vars = [
+        "POSTGRES_HOST",
+        "POSTGRES_PORT",
+        "POSTGRES_DB",
+        "POSTGRES_USER",
+        "POSTGRES_PASSWORD",
+    ]
+    missing_vars = [var for var in required_vars if not os.getenv(var)]
+
+    if missing_vars:
+        raise ValueError(f"Missing required environment variables: {', '.join(missing_vars)}")
+
+    connection_string = (
+        f"postgresql://{os.getenv('POSTGRES_USER')}:{os.getenv('POSTGRES_PASSWORD')}"
+        f"@{os.getenv('POSTGRES_HOST')}:{os.getenv('POSTGRES_PORT')}/{os.getenv('POSTGRES_DB')}"
+    )
+
+    return create_engine(connection_string, echo=echo)
+
+
+def get_db_session(echo: bool = False) -> sessionmaker:
+    """
+    Create a SQLAlchemy sessionmaker for the Home Assistant PostgreSQL database.
+
+    Args:
+        echo: If True, log all SQL statements (default: False)
+
+    Returns:
+        sessionmaker: Database session maker object
+
+    Raises:
+        ValueError: If required environment variables are not set
+    """
+
+    # Create the SQLAlchemy engine
+    engine = _get_engine(echo=echo)
+
+    # Create a session maker
+    session = sessionmaker(bind=engine)
+
+    # Test connection to database
+    with session.begin() as s:
+        s.execute(text("SELECT 1"))
+
+    return session