refactored: to utilise the google adk and production grade agent

app/adk/sessions.py

@@ -0,0 +1,56 @@
+"""ADK Postgres Session Service for GCP Solution Architecture Agent.
+
+Uses google.adk.sessions.SessionService backed by external PostgreSQL database.
+"""
+
+import logging
+import uuid
+from typing import Any, Dict, Optional
+
+from app.adk.compat import Session, SessionService
+from app.database import get_db_manager
+
+logger = logging.getLogger(__name__)
+
+
+class PostgresSessionService(SessionService):
+    """ADK Session Service persisting state to PostgreSQL."""
+
+    def __init__(self) -> None:
+        self.db_manager = get_db_manager()
+
+    def create_session(self, agent_name: str, session_id: Optional[str] = None) -> Session:
+        """Create a new session record in PostgreSQL database."""
+        sid = session_id or str(uuid.uuid4())
+        session = Session(session_id=sid, agent_name=agent_name, state={})
+        self.db_manager.save_session(
+            session_id=sid,
+            agent_name=agent_name,
+            state_data=session.state,
+            metadata={"created_via": "PostgresSessionService"},
+        )
+        logger.info("Created ADK session %s in PostgreSQL database.", sid)
+        return session
+
+    def get_session(self, session_id: str) -> Optional[Session]:
+        """Fetch session state from PostgreSQL database."""
+        sess_data = self.db_manager.get_session(session_id)
+        if not sess_data:
+            return None
+
+        return Session(
+            session_id=sess_data["session_id"],
+            agent_name=sess_data["agent_name"],
+            state=sess_data.get("state_data", {}),
+        )
+
+    def save_session(self, session: Session) -> bool:
+        """Update session state in PostgreSQL database."""
+        success = self.db_manager.save_session(
+            session_id=session.session_id,
+            agent_name=session.agent_name,
+            state_data=session.state,
+        )
+        if success:
+            logger.info("Updated ADK session %s in PostgreSQL database.", session.session_id)
+        return success