fix prometheus invalid metric name (opea-project#849)

* fix

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: Spycsh

comps/cores/mega/http_service.py

@@ -1,6 +1,7 @@
 # Copyright (C) 2024 Intel Corporation
 # SPDX-License-Identifier: Apache-2.0
 
+import re
 from typing import Optional
 
 from fastapi import FastAPI
@@ -35,8 +36,10 @@ def __init__(
         self._app = self._create_app()
 
         # remove part before '@', used by register_microservice() callers, and
-        # part after '/', added by MicroService(), to get real service name
-        suffix = self.title.split("/")[0].split("@")[-1].lower()
+        # part after '/', added by MicroService(), to get real service name, and
+        # convert invalid characters to '_'
+        suffix = re.sub(r"[^a-zA-Z0-9]", "_", self.title.split("/")[0].split("@")[-1].lower())
+
         instrumentator = Instrumentator(
             inprogress_name=f"http_requests_inprogress_{suffix}",
             should_instrument_requests_inprogress=True,