possible solution to fix 1153 added

Author: sthuber90

aws_lambda_powertools/event_handler/api_gateway.py

@@ -651,7 +651,17 @@ def _lookup_exception_handler(self, exp_type: Type) -> Optional[Callable]:
     def _call_exception_handler(self, exp: Exception, route: Route) -> Optional[ResponseBuilder]:
         handler = self._lookup_exception_handler(type(exp))
         if handler:
-            return ResponseBuilder(handler(exp), route)
+            try:
+                return ResponseBuilder(handler(exp), route)
+            except ServiceError as ex:
+                return ResponseBuilder(
+                    Response(
+                        status_code=ex.status_code,
+                        content_type=content_types.APPLICATION_JSON,
+                        body=self._json_dump({"statusCode": ex.status_code, "message": ex.msg}),
+                    ),
+                    route,
+                )
 
         if isinstance(exp, ServiceError):
             return ResponseBuilder(

tests/functional/event_handler/test_api_gateway.py

@@ -9,6 +9,7 @@
 from typing import Dict
 
 import pytest
+from botocore.exceptions import ClientError
 
 from aws_lambda_powertools.event_handler import content_types
 from aws_lambda_powertools.event_handler.api_gateway import (
@@ -1177,6 +1178,29 @@ def get_lambda() -> Response:
     assert result["body"] == "CUSTOM ERROR FORMAT"
 
 
+def test_exception_handler_botocore_client_error(json_dump):
+    # GIVEN
+    app = ApiGatewayResolver()
+
+    @app.exception_handler(ClientError)
+    def client_error(ex: ClientError):
+        raise BadRequestError("Bad request")
+
+    @app.get("/my/path")
+    def get_lambda() -> Response:
+        raise ClientError(error_response={}, operation_name="op-name")
+
+    # WHEN calling the event handler
+    # AND a ClientError is raised
+    result = app(LOAD_GW_EVENT, {})
+
+    # THEN call the exception_handler
+    assert result["statusCode"] == 400
+    assert result["headers"]["Content-Type"] == content_types.APPLICATION_JSON
+    expected = {"statusCode": 400, "message": "Bad request"}
+    assert result["body"] == json_dump(expected)
+
+
 def test_exception_handler_not_found():
     # GIVEN a resolver with an exception handler defined for a 404 not found
     app = ApiGatewayResolver()