flask: add `http.target` and `http.route` to metric attributes (#2621)

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- `opentelemetry-instrumentation-flask` Add `http.route` and `http.target` to metric attributes
+  ([#2621](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2621))
 - `opentelemetry-instrumentation-sklearn` Deprecated the sklearn instrumentation
   ([#2708](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2708))
 - `opentelemetry-instrumentation-pyramid` Record exceptions raised when serving a request

instrumentation/opentelemetry-instrumentation-flask/src/opentelemetry/instrumentation/flask/__init__.py

@@ -266,6 +266,7 @@ from opentelemetry.instrumentation.propagators import (
 )
 from opentelemetry.instrumentation.utils import _start_internal_or_server_span
 from opentelemetry.metrics import get_meter
+from opentelemetry.semconv.attributes.http_attributes import HTTP_ROUTE
 from opentelemetry.semconv.metrics import MetricInstruments
 from opentelemetry.semconv.metrics.http_metrics import (
     HTTP_SERVER_REQUEST_DURATION,
@@ -340,12 +341,16 @@ def _rewrapped_app(
         )
 
         active_requests_counter.add(1, active_requests_count_attrs)
+        request_route = None
 
         def _start_response(status, response_headers, *args, **kwargs):
             if flask.request and (
                 excluded_urls is None
                 or not excluded_urls.url_disabled(flask.request.url)
             ):
+                nonlocal request_route
+                request_route = flask.request.url_rule
+
                 span = flask.request.environ.get(_ENVIRON_SPAN_KEY)
 
                 propagator = get_global_response_propagator()
@@ -388,6 +393,12 @@ def _rewrapped_app(
             duration_attrs_old = otel_wsgi._parse_duration_attrs(
                 attributes, _HTTPStabilityMode.DEFAULT
             )
+
+            if request_route:
+                duration_attrs_old[SpanAttributes.HTTP_TARGET] = str(
+                    request_route
+                )
+
             duration_histogram_old.record(
                 max(round(duration_s * 1000), 0), duration_attrs_old
             )
@@ -395,6 +406,10 @@ def _rewrapped_app(
             duration_attrs_new = otel_wsgi._parse_duration_attrs(
                 attributes, _HTTPStabilityMode.HTTP
             )
+
+            if request_route:
+                duration_attrs_new[HTTP_ROUTE] = str(request_route)
+
             duration_histogram_new.record(
                 max(duration_s, 0), duration_attrs_new
             )

instrumentation/opentelemetry-instrumentation-flask/tests/test_programmatic.py

@@ -85,6 +85,12 @@ def expected_attributes_new(override_attributes):
     return default_attributes
 
 
+_server_duration_attrs_old_copy = _server_duration_attrs_old.copy()
+_server_duration_attrs_old_copy.append("http.target")
+
+_server_duration_attrs_new_copy = _server_duration_attrs_new.copy()
+_server_duration_attrs_new_copy.append("http.route")
+
 _expected_metric_names_old = [
     "http.server.active_requests",
     "http.server.duration",
@@ -95,11 +101,11 @@ _expected_metric_names_new = [
 ]
 _recommended_metrics_attrs_old = {
     "http.server.active_requests": _server_active_requests_count_attrs_old,
-    "http.server.duration": _server_duration_attrs_old,
+    "http.server.duration": _server_duration_attrs_old_copy,
 }
 _recommended_metrics_attrs_new = {
     "http.server.active_requests": _server_active_requests_count_attrs_new,
-    "http.server.request.duration": _server_duration_attrs_new,
+    "http.server.request.duration": _server_duration_attrs_new_copy,
 }
 _server_active_requests_count_attrs_both = (
     _server_active_requests_count_attrs_old
@@ -109,8 +115,8 @@ _server_active_requests_count_attrs_both.extend(
 )
 _recommended_metrics_attrs_both = {
     "http.server.active_requests": _server_active_requests_count_attrs_both,
-    "http.server.duration": _server_duration_attrs_old,
-    "http.server.request.duration": _server_duration_attrs_new,
+    "http.server.duration": _server_duration_attrs_old_copy,
+    "http.server.request.duration": _server_duration_attrs_new_copy,
 }
 
 
@@ -570,6 +576,7 @@ class TestProgrammatic(InstrumentationTest, WsgiTestBase):
         self.client.get("/hello/756")
         expected_duration_attributes = {
             "http.method": "GET",
+            "http.target": "/hello/<int:helloid>",
             "http.host": "localhost",
             "http.scheme": "http",
             "http.flavor": "1.1",
@@ -595,6 +602,7 @@ class TestProgrammatic(InstrumentationTest, WsgiTestBase):
         expected_duration_attributes = {
             "http.request.method": "GET",
             "url.scheme": "http",
+            "http.route": "/hello/<int:helloid>",
             "network.protocol.version": "1.1",
             "http.response.status_code": 200,
         }