Use url.rule instead of request.endpoint for span name flask instrumentation (#1260)

instrumentation/opentelemetry-instrumentation-flask/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Use `url.rule` instead of `request.endpoint` for span name
+  ([#1260](https://github.com/open-telemetry/opentelemetry-python/pull/1260))
 - Record span status and http.status_code attribute on exception 
   ([#1257](https://github.com/open-telemetry/opentelemetry-python/pull/1257))
 

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

@@ -110,9 +110,13 @@ def _before_request():
         return
 
     environ = flask.request.environ
-    span_name = flask.request.endpoint or otel_wsgi.get_default_span_name(
-        environ
-    )
+    span_name = None
+    try:
+        span_name = flask.request.url_rule.rule
+    except AttributeError:
+        pass
+    if span_name is None:
+        span_name = otel_wsgi.get_default_span_name(environ)
     token = context.attach(
         propagators.extract(otel_wsgi.get_header_from_environ, environ)
     )

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

@@ -102,7 +102,7 @@ class TestProgrammatic(InstrumentationTest, TestBase, WsgiTestBase):
 
         span_list = self.memory_exporter.get_finished_spans()
         self.assertEqual(len(span_list), 1)
-        self.assertEqual(span_list[0].name, "_hello_endpoint")
+        self.assertEqual(span_list[0].name, "/hello/<int:helloid>")
         self.assertEqual(span_list[0].kind, trace.SpanKind.SERVER)
         self.assertEqual(span_list[0].attributes, expected_attrs)
 
@@ -154,7 +154,7 @@ class TestProgrammatic(InstrumentationTest, TestBase, WsgiTestBase):
         resp.close()
         span_list = self.memory_exporter.get_finished_spans()
         self.assertEqual(len(span_list), 1)
-        self.assertEqual(span_list[0].name, "_hello_endpoint")
+        self.assertEqual(span_list[0].name, "/hello/<int:helloid>")
         self.assertEqual(span_list[0].kind, trace.SpanKind.SERVER)
         self.assertEqual(span_list[0].attributes, expected_attrs)