fix handling of missing prometheus endpoint

pyinfra/flask.py

@@ -50,11 +50,15 @@ def set_up_probing_webserver():
         try:
             resp = requests.get(f"{CONFIG.rabbitmq.callback.analysis_endpoint}/prometheus")
             resp.raise_for_status()
-            return resp.text
+        except ConnectionError:
-        except Exception as err:
+            return ""
-            if not informed_about_missing_prometheus_endpoint:
+        except requests.exceptions.HTTPError as err:
-                logger.warning(f"Got no metrics from analysis prometheus endpoint: {err}")
+            if resp.status_code == 404:
-                informed_about_missing_prometheus_endpoint = True
+                if not informed_about_missing_prometheus_endpoint:
-            return resp
+                    logger.warning(f"Got no metrics from analysis prometheus endpoint: {err}")
+                    informed_about_missing_prometheus_endpoint = True
+            else:
+                raise err
+        return resp.text
 
     return app