Is LoggingMiddleware and Server Sent Event SSE are compatible?

[4l1fe]

Hey. I'm not sure about a reason why the error occured

ERROR ֆ�,-245742448 exception raised on http connection to route /htmx/notifications

Traceback (most recent call last):
  File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/response/streaming.py", line 94, in _listen_for_disconnect
    message = await receive()
              ^^^^^^^^^^^^^^^
  File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/uvicorn/protocols/http/httptools_impl.py", line 596, in receive
    await self.message_event.wait()
  File "/home/user/.pyenv/versions/3.11.2/lib/python3.11/asyncio/locks.py", line 213, in wait
    await fut
asyncio.exceptions.CancelledError: Cancelled by cancel scope 7fbdf43918d0

During handling of the above exception, another exception occurred:

  + Exception Group Traceback (most recent call last):
  |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/middleware/exceptions/middleware.py", line 192, in __call__
  |     await self.app(scope, receive, send)
  |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/routes/http.py", line 86, in handle
  |     await response(scope, receive, send)
  |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/response/base.py", line 197, in __call__
  |     await self.send_body(send=send, receive=receive)
  |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/response/streaming.py", line 132, in send_body
  |     async with create_task_group() as task_group:
  |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/anyio/_backends/_asyncio.py", line 678, in __aexit__
  |     raise BaseExceptionGroup(
  | ExceptionGroup: unhandled errors in a TaskGroup (1 sub-exception)
  +-+---------------- 1 ----------------
    | Traceback (most recent call last):
    |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/response/streaming.py", line 117, in _stream
    |     await send(stream_event)
    |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/middleware/logging.py", line 229, in send_wrapper
    |     self.log_response(scope=scope)
    |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/middleware/logging.py", line 138, in log_response
    |     extracted_data = self.extract_response_data(scope=scope)
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/middleware/logging.py", line 197, in extract_response_data
    |     connection_state.log_context.pop(HTTP_RESPONSE_START),
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    | KeyError: 'http.response.start'
    +------------------------------------
Traceback (most recent call last):
  File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/response/streaming.py", line 134, in send_body
    await self._listen_for_disconnect(cancel_scope=task_group.cancel_scope, receive=receive)
  File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/response/streaming.py", line 100, in _listen_for_disconnect
    await self._listen_for_disconnect(cancel_scope=cancel_scope, receive=receive)
  File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/response/streaming.py", line 94, in _listen_for_disconnect
    message = await receive()
              ^^^^^^^^^^^^^^^
  File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/uvicorn/protocols/http/httptools_impl.py", line 596, in receive
    await self.message_event.wait()
  File "/home/user/.pyenv/versions/3.11.2/lib/python3.11/asyncio/locks.py", line 213, in wait
    await fut
asyncio.exceptions.CancelledError: Cancelled by cancel scope 7fbdf43918d0

During handling of the above exception, another exception occurred:

  + Exception Group Tr/userceback (most recent call last):
  |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/middleware/exceptions/middleware.py", line 192, in __call__
  |     await self.app(scope, receive, send)
  |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/routes/http.py", line 86, in handle
  |     await response(scope, receive, send)
  |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/response/base.py", line 197, in __call__
  |     await self.send_body(send=send, receive=receive)
  |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/response/streaming.py", line 132, in send_body
  |     async with create_task_group() as task_group:
  |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/anyio/_backends/_asyncio.py", line 678, in __aexit__
  |     raise BaseExceptionGroup(
  | ExceptionGroup: unhandled errors in a TaskGroup (1 sub-exception)
  +-+---------------- 1 ----------------
    | Traceback (most recent call last):
    |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/response/streaming.py", line 117, in _stream
    |     await send(stream_event)
    |   File "/home/vol/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/middleware/logging.py", line 229, in send_wrapper
    |     self.log_response(scope=scope)
    |   File "/home/user/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/middleware/logging.py", line 138, in log_response
    |     extracted_data = self.extract_response_data(scope=scope)
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |   File "/home/vol/.pyenv/versions/3.11.2/envs/service/lib/python3.11/site-packages/litestar/middleware/logging.py", line 197, in extract_response_data
    |     connection_state.log_context.pop(HTTP_RESPONSE_START),
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    | KeyError: 'http.response.start'
    +------------------------------------

But if i exclude the sse endpoint then the logging middleware works well

logging_middleware_config = LoggingMiddlewareConfig(
                                exclude=['/htmx/notifications']
)

Controller code

class HTMXController(Controller):
    path ='/htmx'

    @get(path='/notifications')
    async def subscribe_notifications(self, request: HTMXRequest, state: State) -> ServerSentEvent:
        return ServerSentEvent(state.sse_reg.generate_event(request, 'sse.html'),
                            event_type='server_message')

That is why i think logging SSE is not supported.

[euri10]

can confirm this triggers just adding a simple config in a test:

diff --git a/tests/unit/test_response/test_sse.py b/tests/unit/test_response/test_sse.py
index eade2426d..2e48ac2be 100644
--- a/tests/unit/test_response/test_sse.py
+++ b/tests/unit/test_response/test_sse.py
@@ -7,6 +7,7 @@ from httpx_sse import aconnect_sse
 
 from litestar import get
 from litestar.exceptions import ImproperlyConfiguredException
+from litestar.middleware.logging import LoggingMiddlewareConfig
 from litestar.response import ServerSentEvent
 from litestar.response.sse import ServerSentEventMessage
 from litestar.testing import create_async_test_client
@@ -25,7 +26,7 @@ async def test_sse_steaming_response() -> None:
 
         return ServerSentEvent(content=generator, event_id="123", event_type="special", retry_duration=1000)
 
-    async with create_async_test_client(handler) as client:
+    async with create_async_test_client(handler, middleware=[LoggingMiddlewareConfig().middleware]) as client:
         async with aconnect_sse(client, "GET", f"{client.base_url}/test") as event_source:
             events = [sse async for sse in event_source.aiter_sse()]
             assert len(events) == 5