RD-14044-OTEL-FastAPI-inbound-request-body-not-parsed-correctly-1 (#954)

* fastapi request.body fix

Author: eugene-lumigo

src/lumigo_opentelemetry/instrumentations/fastapi/parsers/__init__.py

@@ -42,10 +42,16 @@ async def new_otel_receive():  # type: ignore
             return_value = await original_otel_receive()
             with lumigo_safe_execute("FastAPIParser: new_otel_receive"):
                 with instance.tracer.start_as_current_span("receive_body") as send_span:
-                    send_span.set_attribute(
-                        "http.request.body",
-                        dump_with_context("requestBody", return_value),
-                    )
+                    if isinstance(return_value, dict) and "body" in return_value:
+                        send_span.set_attribute(
+                            "http.request.body",
+                            dump_with_context("requestBody", return_value.get("body")),
+                        )
+                    else:
+                        send_span.set_attribute(
+                            "http.request.body",
+                            dump_with_context("requestBody", return_value),
+                        )
             return return_value
 
         return new_otel_receive

src/test/integration/fastapi/tests/test_fastapi.py

@@ -120,6 +120,12 @@ def test_requests_instrumentation(self):
                     internals, "http.request.body"
                 )
             )
+            self.assertEqual(
+                spans_container.get_attribute_from_list_of_spans(
+                    internals, "http.request.body"
+                ),
+                '{"a": "b"}',
+            )
             self.assertIsNotNone(
                 spans_container.get_attribute_from_list_of_spans(
                     internals, "http.response.headers"