Fix exception handling for events with requestContext (#2418)

* Fix exception handling for events with requestContext

* added entry to changelog

* reformatted with black

---------

Co-authored-by: Diego Hurtado <ocelotl@users.noreply.github.com>

CHANGELOG.md

@@ -37,6 +37,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#2363](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2363))
 - `opentelemetry-instrumentation-boto3sqs` Instrument Session and resource
   ([#2161](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2161))
+- `opentelemetry-instrumentation-aws-lambda` Fix exception handling for events with requestContext
+  ([#2418](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2418))
 - Use sqlalchemy version in sqlalchemy commenter instead of opentelemetry library version
   ([#2404](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2404))
 

instrumentation/opentelemetry-instrumentation-aws-lambda/src/opentelemetry/instrumentation/aws_lambda/__init__.py

@@ -365,6 +365,7 @@ def _instrument(
                 )
 
             exception = None
+            result = None
             try:
                 result = call_wrapped(*args, **kwargs)
             except Exception as exc:  # pylint: disable=W0703

instrumentation/opentelemetry-instrumentation-aws-lambda/tests/test_aws_lambda_instrumentation_manual.py

@@ -436,6 +436,31 @@ class TestAwsLambdaInstrumentor(TestBase):
 
         exc_env_patch.stop()
 
+    def test_lambda_handles_handler_exception_with_api_gateway_proxy_event(
+        self,
+    ):
+        exc_env_patch = mock.patch.dict(
+            "os.environ",
+            {_HANDLER: "tests.mocks.lambda_function.handler_exc"},
+        )
+        exc_env_patch.start()
+        AwsLambdaInstrumentor().instrument()
+        # instrumentor re-raises the exception
+        with self.assertRaises(Exception):
+            mock_execute_lambda(
+                {"requestContext": {"http": {"method": "GET"}}}
+            )
+
+        spans = self.memory_exporter.get_finished_spans()
+        self.assertEqual(len(spans), 1)
+        span = spans[0]
+        self.assertEqual(span.status.status_code, StatusCode.ERROR)
+        self.assertEqual(len(span.events), 1)
+        event = span.events[0]
+        self.assertEqual(event.name, "exception")
+
+        exc_env_patch.stop()
+
     def test_uninstrument(self):
         AwsLambdaInstrumentor().instrument()