fix: Update falcon instrumentation to follow semantic conventions

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Fixed
+
+- Update falcon instrumentation to follow semantic conventions
+  ([#1824](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1824))
+
 ### Added
 
 - Make Flask request span attributes available for `start_span`. 

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

@@ -428,7 +428,6 @@ def process_resource(self, req, resp, resource, params):
 
         resource_name = resource.__class__.__name__
         span.set_attribute("falcon.resource", resource_name)
-        span.update_name(f"{resource_name}.on_{req.method.lower()}")
 
     def process_response(
         self, req, resp, resource, req_succeeded=None
@@ -483,6 +482,12 @@ def process_response(
                 response_headers = resp.headers
 
             if span.is_recording() and span.kind == trace.SpanKind.SERVER:
+                # Check if low-cardinality route is available as per semantic-conventions
+                if req.uri_template:
+                    span.update_name(f"{req.method} {req.uri_template}")
+                else:
+                    span.update_name(f"{req.method}")
+
                 custom_attributes = (
                     otel_wsgi.collect_custom_response_headers_attributes(
                         response_headers.items()

instrumentation/opentelemetry-instrumentation-falcon/tests/app.py

@@ -61,6 +61,13 @@ def on_get(self, _, resp):
         resp.set_header("my-secret-header", "my-secret-value")
 
 
+class UserResource:
+    def on_get(self, req, resp, user_id):
+        # pylint: disable=no-member
+        resp.status = falcon.HTTP_200
+        resp.body = f"Hello user {user_id}"
+
+
 def make_app():
     _parsed_falcon_version = package_version.parse(falcon.__version__)
     if _parsed_falcon_version < package_version.parse("3.0.0"):
@@ -76,4 +83,6 @@ def make_app():
     app.add_route(
         "/test_custom_response_headers", CustomResponseHeaderResource()
     )
+    app.add_route("/user/{user_id}", UserResource())
+
     return app

instrumentation/opentelemetry-instrumentation-falcon/tests/test_falcon.py

@@ -110,7 +110,7 @@ def _test_method(self, method):
         spans = self.memory_exporter.get_finished_spans()
         self.assertEqual(len(spans), 1)
         span = spans[0]
-        self.assertEqual(span.name, f"HelloWorldResource.on_{method.lower()}")
+        self.assertEqual(span.name, f"{method} /hello")
         self.assertEqual(span.status.status_code, StatusCode.UNSET)
         self.assertEqual(
             span.status.description,
@@ -145,7 +145,7 @@ def test_404(self):
         spans = self.memory_exporter.get_finished_spans()
         self.assertEqual(len(spans), 1)
         span = spans[0]
-        self.assertEqual(span.name, "GET /does-not-exist")
+        self.assertEqual(span.name, "GET")
         self.assertEqual(span.status.status_code, StatusCode.UNSET)
         self.assertSpanHasAttributes(
             span,
@@ -177,7 +177,7 @@ def test_500(self):
         spans = self.memory_exporter.get_finished_spans()
         self.assertEqual(len(spans), 1)
         span = spans[0]
-        self.assertEqual(span.name, "ErrorResource.on_get")
+        self.assertEqual(span.name, "GET /error")
         self.assertFalse(span.status.is_ok)
         self.assertEqual(span.status.status_code, StatusCode.ERROR)
         self.assertEqual(
@@ -206,6 +206,33 @@ def test_500(self):
                 span.attributes[SpanAttributes.NET_PEER_IP], "127.0.0.1"
             )
 
+    def test_url_template(self):
+        self.client().simulate_get("/user/123")
+        spans = self.memory_exporter.get_finished_spans()
+        self.assertEqual(len(spans), 1)
+        span = spans[0]
+        self.assertEqual(span.name, "GET /user/{user_id}")
+        self.assertEqual(span.status.status_code, StatusCode.UNSET)
+        self.assertEqual(
+            span.status.description,
+            None,
+        )
+        self.assertSpanHasAttributes(
+            span,
+            {
+                SpanAttributes.HTTP_METHOD: "GET",
+                SpanAttributes.HTTP_SERVER_NAME: "falconframework.org",
+                SpanAttributes.HTTP_SCHEME: "http",
+                SpanAttributes.NET_HOST_PORT: 80,
+                SpanAttributes.HTTP_HOST: "falconframework.org",
+                SpanAttributes.HTTP_TARGET: "/",
+                SpanAttributes.NET_PEER_PORT: "65133",
+                SpanAttributes.HTTP_FLAVOR: "1.1",
+                "falcon.resource": "UserResource",
+                SpanAttributes.HTTP_STATUS_CODE: 200,
+            },
+        )
+
     def test_uninstrument(self):
         self.client().simulate_get(path="/hello")
         spans = self.memory_exporter.get_finished_spans()