Conditionally create server spans for flask (#828)

* Making span as internal in presence of a span in current context

* Updating changelog

* Removing extra print statements

* Resolving comments: Setting current context as parent in its presence

* Ignoring pylint check as django.conf.urls.url is removed in django 4.0
Django release notes: https://docs.djangoproject.com/en/4.0/releases/4.0/

* Removing changes in django files

CHANGELOG.md

@@ -23,6 +23,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `opentelemetry-instrumentation-tornado` Add support instrumentation for Tornado 5.1.1
   ([#812](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/812))
 
+- `opentelemetry-instrumentation-flask` Flask: Conditionally create SERVER spans
+  ([#828](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/828))
+  
 ## [1.7.1-0.26b1](https://github.com/open-telemetry/opentelemetry-python/releases/tag/v1.7.0-0.26b0) - 2021-11-11
 
 - `opentelemetry-instrumentation-aws-lambda` Add instrumentation for AWS Lambda Service - pkg metadata files (Part 1/2)

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

@@ -176,15 +176,24 @@ def _wrapped_before_request(
             return
         flask_request_environ = flask.request.environ
         span_name = get_default_span_name()
-        token = context.attach(
+
-            extract(flask_request_environ, getter=otel_wsgi.wsgi_getter)
+        token = ctx = span_kind = None
-        )
+
+        if trace.get_current_span() is trace.INVALID_SPAN:
+            ctx = extract(flask_request_environ, getter=otel_wsgi.wsgi_getter)
+            token = context.attach(ctx)
+            span_kind = trace.SpanKind.SERVER
+        else:
+            ctx = context.get_current()
+            span_kind = trace.SpanKind.INTERNAL
 
         span = tracer.start_span(
             span_name,
-            kind=trace.SpanKind.SERVER,
+            ctx,
+            kind=span_kind,
             start_time=flask_request_environ.get(_ENVIRON_STARTTIME_KEY),
         )
+
         if request_hook:
             request_hook(span, flask_request_environ)
 
@@ -229,6 +238,8 @@ def _wrapped_teardown_request(excluded_urls=None):
             activation.__exit__(
                 type(exc), exc, getattr(exc, "__traceback__", None)
             )
+
+        if flask.request.environ.get(_ENVIRON_TOKEN, None):
             context.detach(flask.request.environ.get(_ENVIRON_TOKEN))
 
     return _teardown_request

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

@@ -23,6 +23,7 @@ from opentelemetry.instrumentation.propagators import (
     get_global_response_propagator,
     set_global_response_propagator,
 )
+from opentelemetry.instrumentation.wsgi import OpenTelemetryMiddleware
 from opentelemetry.sdk.resources import Resource
 from opentelemetry.semconv.trace import SpanAttributes
 from opentelemetry.test.test_base import TestBase
@@ -413,3 +414,31 @@ class TestProgrammaticCustomTracerProviderWithoutApp(
             span_list[0].resource.attributes["service.name"],
             "flask-api-no-app",
         )
+
+
+class TestProgrammaticWrappedWithOtherFramework(
+    InstrumentationTest, TestBase, WsgiTestBase
+):
+    def setUp(self):
+        super().setUp()
+
+        self.app = Flask(__name__)
+        self.app.wsgi_app = OpenTelemetryMiddleware(self.app.wsgi_app)
+        FlaskInstrumentor().instrument_app(self.app)
+        self._common_initialization()
+
+    def tearDown(self) -> None:
+        super().tearDown()
+        with self.disable_logging():
+            FlaskInstrumentor().uninstrument_app(self.app)
+
+    def test_mark_span_internal_in_presence_of_span_from_other_framework(self):
+        resp = self.client.get("/hello/123")
+        self.assertEqual(200, resp.status_code)
+        resp.get_data()
+        span_list = self.memory_exporter.get_finished_spans()
+        self.assertEqual(trace.SpanKind.INTERNAL, span_list[0].kind)
+        self.assertEqual(trace.SpanKind.SERVER, span_list[1].kind)
+        self.assertEqual(
+            span_list[0].parent.span_id, span_list[1].context.span_id
+        )