More verbose errors (#109)

Author: s3rius

taskiq/cli/worker/run.py

@@ -128,6 +128,8 @@ def run_worker(args: WorkerArgs) -> None:  # noqa: WPS213
     and joins them all.
 
     :param args: CLI arguments.
+
+    :raises ValueError: if reload flag is used, but dependencies are not installed.
     """
     logging.basicConfig(
         level=logging.getLevelName(args.log_level),
@@ -137,10 +139,12 @@ def run_worker(args: WorkerArgs) -> None:  # noqa: WPS213
     logger.info("Starting %s worker processes.", args.workers)
 
     observer = None
-    if Observer is not None:
-        observer = Observer()
 
-    if observer is not None and args.reload:
+    if args.reload and Observer is None:
+        raise ValueError("To use '--reload' flag, please install 'taskiq[reload]'.")
+
+    if Observer is not None and args.reload:
+        observer = Observer()
         observer.start()
         args.workers = 1
         logging.warning(

taskiq/middlewares/prometheus_middleware.py

@@ -57,11 +57,10 @@ def __init__(
                 Histogram,
                 start_http_server,
             )
-        except ImportError:
-            logger.warn(
-                "Cannot initialize metrics. Please install 'taskiq[metrics]' extra.",
-            )
-            raise
+        except ImportError as exc:
+            raise ImportError(
+                "Cannot initialize metrics. Please install 'taskiq[metrics]'.",
+            ) from exc
 
         self.found_errors = Counter(
             "found_errors",