code changes to resolve conditional server span creation for WSGI (open-telemetry#454)

Author: sanketmehta28

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

@@ -280,11 +280,17 @@ def __call__(self, environ, start_response):
             start_response: The WSGI start_response callable.
         """
 
-        token = context.attach(extract(environ, getter=wsgi_getter))
+        token = ctx = None
+        span_kind = trace.SpanKind.INTERNAL
+        if trace.get_current_span() is trace.INVALID_SPAN:
+            ctx = extract(environ, getter=wsgi_getter)
+            token = context.attach(ctx)
+            span_kind = trace.SpanKind.SERVER
 
         span = self.tracer.start_span(
             get_default_span_name(environ),
-            kind=trace.SpanKind.SERVER,
+            context=ctx,
+            kind=span_kind,
             attributes=collect_request_attributes(environ),
         )
 
@@ -308,7 +314,8 @@ def __call__(self, environ, start_response):
             if span.is_recording():
                 span.set_status(Status(StatusCode.ERROR, str(ex)))
             span.end()
-            context.detach(token)
+            if token is not None:
+                context.detach(token)
             raise
 
 
@@ -324,7 +331,8 @@ def _end_span_after_iterating(iterable, span, tracer, token):
         if close:
             close()
         span.end()
-        context.detach(token)
+        if token is not None:
+            context.detach(token)
 
 
 # TODO: inherit from opentelemetry.instrumentation.propagators.Setter

instrumentation/opentelemetry-instrumentation-wsgi/tests/test_wsgi_middleware.py

@@ -414,5 +414,35 @@ def test_basic_wsgi_call(self):
         self.validate_response(response, exporter)
 
 
+class TestWsgiMiddlewareWrappedWithAnotherFramework(WsgiTestBase):
+    def test_mark_span_internal_in_presence_of_span_from_other_framework(self):
+        tracer_provider, exporter = TestBase.create_tracer_provider()
+        tracer = tracer_provider.get_tracer(__name__)
+
+        with tracer.start_as_current_span(
+            "test", kind=trace_api.SpanKind.SERVER
+        ) as parent_span:
+            app = otel_wsgi.OpenTelemetryMiddleware(
+                simple_wsgi, tracer_provider=tracer_provider
+            )
+            response = app(self.environ, self.start_response)
+            while True:
+                try:
+                    value = next(response)
+                    self.assertEqual(value, b"*")
+                except StopIteration:
+                    break
+
+            span_list = exporter.get_finished_spans()
+
+            self.assertEqual(trace_api.SpanKind.INTERNAL, span_list[0].kind)
+            self.assertEqual(trace_api.SpanKind.SERVER, parent_span.kind)
+
+            # internal span should be child of the parent span we have provided
+            self.assertEqual(
+                parent_span.context.span_id, span_list[0].parent.span_id
+            )
+
+
 if __name__ == "__main__":
     unittest.main()