fix(metrics): use rule as path

Using the real path as metric created useless metrics. When using a
dynamic rule, it creates unique paths with every metric, which makes it
impossible to aggregate metrics to the same endpoint.

Author: alexppg

pyms/flask/services/metrics.py

@@ -31,8 +31,8 @@ def before_request(self):  # pylint: disable=R0201
 
     def after_request(self, response):
         request_latency = time.time() - request.start_time
-        FLASK_REQUEST_LATENCY.labels(self.app_name, request.method, request.path, response.status_code).observe(request_latency)
-        FLASK_REQUEST_COUNT.labels(self.app_name, request.method, request.path, response.status_code).inc()
+        FLASK_REQUEST_LATENCY.labels(self.app_name, request.method, request.url_rule.rule, response.status_code).observe(request_latency)
+        FLASK_REQUEST_COUNT.labels(self.app_name, request.method, request.url_rule.rule, response.status_code).inc()
 
         return response