fix: Clean up logging and metrics handling across the application

Author: milsman2

src/sample_python_app/app/lifecycle.py

@@ -15,7 +15,7 @@
 def start_metrics_server(port: int) -> None:
     """Start the Prometheus metrics server on the specified port."""
     if _port_in_use(port):
-        logger.error("Port %s already in use; metrics disabled", port)
+        logger.error(f"Port {port} already in use; metrics disabled")
         return
 
     logger.info(f"Starting Prometheus metrics on 0.0.0.0:{port}")

src/sample_python_app/app/runner.py

@@ -3,17 +3,12 @@
 Handles fetching, validation, and display of astronomical data.
 """
 
-import json
 import time
 from datetime import date
 
-import httpx
-from pydantic import ValidationError
-
 from sample_python_app.core import (
     FETCH_COUNTER,
     FETCH_DURATION,
-    FETCH_ERRORS,
     setup_logger,
     weather_settings,
 )
@@ -41,30 +36,31 @@ def __init__(self, client: CustomHTTPClient) -> None:
         self.client = client
 
     def fetch(self, *, exit_on_error: bool = True) -> None:
-        """Fetch astronomical data and display if not already displayed today."""
+        """Fetch astronomical data and display if not already shown today."""
         lat = weather_settings.LOCATION.latitude
         lon = weather_settings.LOCATION.longitude
-        logger.info(f"Using latitude={lat} longitude={lon}")
+
+        logger.info("Using latitude=%s longitude=%s", lat, lon)
+
         start = time.time()
+
         try:
             astro = fetch_astronomical_data_from_api(lat, lon, client=self.client)
             forecast = fetch_hourly_forecast_from_api(lat, lon, client=self.client)
             FETCH_COUNTER.inc()
-        except (
-            httpx.HTTPStatusError,
-            httpx.RequestError,
-            ValidationError,
-            json.JSONDecodeError,
-            AppError,
-        ) as exc:
-            self._handle_fetch_error(exc, exit_on_error)
+        except AppError as exc:
+            logger.error("Weather fetch failed: %s", exc)
+            if exit_on_error:
+                raise SystemExit(1) from None
             return
         finally:
             FETCH_DURATION.observe(time.time() - start)
-        today_str = date.today().isoformat()
-        if self._last_displayed_day != today_str:
+
+        today = date.today().isoformat()
+
+        if self._last_displayed_day != today:
             display_astronomical_data(astro, forecast)
-            self._last_displayed_day = today_str
+            self._last_displayed_day = today
 
     def reset_display(self):
         """Reset the last displayed day so display will occur again."""
@@ -82,22 +78,6 @@ def close(self) -> None:
             except Exception:
                 logger.exception("Error closing HTTP client in AstroFetcher")
 
-    def _handle_fetch_error(self, exc: Exception, exit_on_error: bool) -> None:
-        FETCH_ERRORS.inc()
-        if isinstance(exc, httpx.HTTPStatusError):
-            logger.error("HTTP status error: %s", exc)
-        elif isinstance(exc, httpx.RequestError):
-            logger.error("Network error: %s", exc)
-        elif isinstance(exc, ValidationError):
-            logger.error("Validation error: %s", exc)
-        elif isinstance(exc, json.JSONDecodeError):
-            logger.error("JSON decode error: %s", exc)
-        else:
-            logger.exception("Unexpected error")
-        if exit_on_error:
-            raise SystemExit(1) from exc
-        raise AppError(str(exc)) from exc
-
 
 runner_client = CustomHTTPClient(
     headers=weather_settings.WEATHER_HEADERS,

src/sample_python_app/core/__init__.py

@@ -6,6 +6,9 @@
     FETCH_COUNTER,
     FETCH_DURATION,
     FETCH_ERRORS,
+    HTTP_REQUEST_DURATION,
+    HTTP_REQUEST_EXCEPTIONS,
+    HTTP_REQUESTS,
 )
 
 __all__ = [
@@ -16,4 +19,7 @@
     "FETCH_COUNTER",
     "FETCH_DURATION",
     "FETCH_ERRORS",
+    "HTTP_REQUESTS",
+    "HTTP_REQUEST_EXCEPTIONS",
+    "HTTP_REQUEST_DURATION",
 ]

src/sample_python_app/core/metrics.py

@@ -14,10 +14,27 @@
     "fetch_duration_seconds",
     "Duration of astronomical data fetches in seconds",
 )
-
+HTTP_REQUESTS = Counter(
+    "http_requests_total",
+    "Total HTTP requests made",
+    ["method", "host", "path", "status_code"],
+)
+HTTP_REQUEST_EXCEPTIONS = Counter(
+    "http_request_exceptions_total",
+    "Total HTTP request exceptions",
+    ["method", "host", "path", "exception_type"],
+)
+HTTP_REQUEST_DURATION = Histogram(
+    "http_request_duration_seconds",
+    "HTTP request latency in seconds",
+    ["method", "host", "path"],
+)
 __all__ = [
     "FETCH_COUNTER",
     "FETCH_ERRORS",
     "FETCH_DURATION",
+    "HTTP_REQUESTS",
+    "HTTP_REQUEST_EXCEPTIONS",
+    "HTTP_REQUEST_DURATION",
     "start_http_server",
 ]

src/sample_python_app/exceptions/__init__.py

@@ -2,6 +2,9 @@
 
 from sample_python_app.exceptions.custom import (
     AppError,
+    HTTPTimeoutError,
+    NetworkError,
+    ServiceError,
 )
 
-__all__ = ["AppError"]
+__all__ = ["AppError", "HTTPTimeoutError", "NetworkError", "ServiceError"]

src/sample_python_app/exceptions/custom.py

@@ -1,6 +1,38 @@
 """Custom exceptions for the sample_python_app project."""
 
 
+class HTTPTimeoutError(Exception):
+    """Raised when an HTTP request times out."""
+
+    def __init__(self, message: str) -> None:
+        """Initialize the HTTPTimeoutError with a message."""
+        super().__init__(message)
+
+
+class NetworkError(Exception):
+    """Raised when a network-level error occurs.
+
+    (connection refused, DNS failure, etc.).
+    """
+
+    def __init__(self, message: str) -> None:
+        """Initialize the NetworkError with a message."""
+        super().__init__(message)
+
+
+class ServiceError(Exception):
+    """Raised when the HTTP response returns an error status (4xx or 5xx)."""
+
+    def __init__(self, status_code: int, body: str | None = None) -> None:
+        """Initialize the ServiceError with status code and optional response body."""
+        self.status_code = status_code
+        self.body = body
+        msg = f"Service returned status {status_code}"
+        if body:
+            msg += f": {body}"
+        super().__init__(msg)
+
+
 class AppError(Exception):
     """Base exception for the application."""