Fix runtime logging and frontend app regressions

backend/data/polling_price_manager.py

@@ -15,6 +15,9 @@ from backend.data.provider_utils import normalize_symbol
 logger = logging.getLogger(__name__)
 
 
+_SUPPRESSED_LOG_EVERY = 20
+
+
 class PollingPriceManager:
     """Polling-based price manager using Finnhub or yfinance."""
 
@@ -43,6 +46,7 @@ class PollingPriceManager:
         self.latest_prices: Dict[str, float] = {}
         self.open_prices: Dict[str, float] = {}
         self.price_callbacks: List[Callable] = []
+        self._failure_counts: Dict[str, int] = {}
 
         self.running = False
         self._thread: Optional[threading.Thread] = None
@@ -77,6 +81,8 @@ class PollingPriceManager:
         for symbol in self.subscribed_symbols:
             try:
                 quote_data = self._fetch_quote(symbol)
+                if not isinstance(quote_data, dict):
+                    raise ValueError(f"{symbol}: Empty quote payload")
 
                 current_price = quote_data.get("c")
                 open_price = quote_data.get("o")
@@ -103,6 +109,13 @@ class PollingPriceManager:
                 )
 
                 self.latest_prices[symbol] = current_price
+                previous_failures = self._failure_counts.pop(symbol, 0)
+                if previous_failures > 0:
+                    logger.info(
+                        "%s quote polling recovered after %d consecutive failures",
+                        symbol,
+                        previous_failures,
+                    )
 
                 price_data = {
                     "symbol": symbol,
@@ -128,7 +141,20 @@ class PollingPriceManager:
                 )
 
             except Exception as e:
-                logger.error(f"Failed to fetch {symbol} price: {e}")
+                failure_count = self._failure_counts.get(symbol, 0) + 1
+                self._failure_counts[symbol] = failure_count
+                message = f"Failed to fetch {symbol} price: {e}"
+
+                if failure_count == 1:
+                    logger.warning(message)
+                elif failure_count % _SUPPRESSED_LOG_EVERY == 0:
+                    logger.warning(
+                        "%s (repeated %d times; suppressing intermediate failures)",
+                        message,
+                        failure_count,
+                    )
+                else:
+                    logger.debug(message)
 
     def _fetch_quote(self, symbol: str) -> Dict[str, float]:
         """Fetch a normalized quote payload from the configured provider."""
@@ -136,7 +162,10 @@ class PollingPriceManager:
             return self._fetch_yfinance_quote(symbol)
         if not self.finnhub_client:
             raise ValueError("Finnhub API key required for finnhub polling")
-        return self.finnhub_client.quote(symbol)
+        quote = self.finnhub_client.quote(symbol)
+        if not isinstance(quote, dict):
+            raise ValueError(f"{symbol}: Invalid Finnhub quote payload")
+        return quote
 
     def _fetch_yfinance_quote(self, symbol: str) -> Dict[str, float]:
         """Fetch quote data from yfinance and normalize to Finnhub-like keys."""
@@ -162,6 +191,8 @@ class PollingPriceManager:
 
         if current_price is None:
             history = ticker.history(period="1d", interval="1m", auto_adjust=False)
+            if history is None:
+                raise ValueError(f"{symbol}: yfinance returned no history frame")
             if history.empty:
                 raise ValueError(f"{symbol}: No yfinance quote data")
             latest = history.iloc[-1]