Harden strategy resume failure handling

backend/app/services/strategy_service.py

@@ -328,16 +328,32 @@ def _validate_live_broker_session(user_id: str):
     if not broker_state.get("connected") or broker_name != "ZERODHA":
         return False, broker_state, "broker_not_connected"
 
+    try:
         session = get_session(user_id)
+    except Exception as exc:
+        print(f"[STRATEGY] failed to load Zerodha session for {user_id}: {exc}", flush=True)
+        set_broker_auth_state(user_id, "EXPIRED")
+        return False, broker_state, "broker_auth_required"
+
     if not session:
         set_broker_auth_state(user_id, "EXPIRED")
         return False, broker_state, "broker_auth_required"
 
+    api_key = str(session.get("api_key") or "").strip()
+    access_token = str(session.get("access_token") or "").strip()
+    if not api_key or not access_token:
+        set_broker_auth_state(user_id, "EXPIRED")
+        return False, broker_state, "broker_auth_required"
+
     try:
-        fetch_funds(session["api_key"], session["access_token"])
+        fetch_funds(api_key, access_token)
     except KiteTokenError:
         set_broker_auth_state(user_id, "EXPIRED")
         return False, broker_state, "broker_auth_required"
+    except Exception as exc:
+        print(f"[STRATEGY] failed to validate Zerodha session for {user_id}: {exc}", flush=True)
+        set_broker_auth_state(user_id, "EXPIRED")
+        return False, broker_state, "broker_auth_required"
 
     set_broker_auth_state(user_id, "VALID")
     return True, broker_state, "ok"
@@ -612,14 +628,28 @@ def resume_strategy(user_id: str):
             }
 
     if not engine_external:
+        try:
             engine_config = _build_engine_config(user_id, run_id, None)
+        except Exception as exc:
+            return {
+                "status": "resume_failed",
+                "run_id": run_id,
+                "message": f"Unable to load the saved strategy state: {exc}",
+            }
         if not engine_config:
             return {
                 "status": "resume_failed",
                 "run_id": run_id,
                 "message": "Saved strategy configuration is incomplete.",
             }
+        try:
             started = start_engine(engine_config)
+        except Exception as exc:
+            return {
+                "status": "resume_failed",
+                "run_id": run_id,
+                "message": f"Unable to resume the strategy engine: {exc}",
+            }
         if not started:
             return {
                 "status": "resume_failed",