Flyte enables production-grade orchestration for machine learning workflows and data processing created to accelerate local workflows to production.

Flyte

Hi <#CP2HDHKE1|>!!
I want to write a failure task on workflow failure which print the error and tasks name (To send a slack notification), but I seeing that error field is set to None. Do you know what could be the issue? Code in the :thread:

```@task  # type: ignore[misc]
def current_time_task(name: str) -&gt; str:
    """Dummy task which prints current time."""
    current_time = datetime.datetime.now(datetime.timezone.utc)
    task_output = f"Hello, {name}!  This is my task running at {current_time}"
    <http://logger.info|logger.info>(task_output)
    raise ValueError("Fail!")
    return task_output


@task
def failure_cb(name: str, err: FlyteError | None) -&gt; str:
    print(f"Handling error: {err}")
    return name


@workflow(on_failure=failure_cb)  # type: ignore[misc]
def dummy_workflow(name: str) -&gt; str:
    """Dummy workflow."""
    return current_time_task(name=name)  # type: ignore[no-any-return]```


I believe pipe "|" is not well handled in flyte, try Optional[FlyteError], with typing.Optional

Screenshot 2024-12-11 at 8.24.56 AM.png

```-def failure_cb(name: str, err: FlyteError | None) -&gt; str:
+def failure_cb(name: str, err: typing.Optional[FlyteError] = None) -&gt; str:  # noqa: UP007
     print(f"Handling error: {err}")
     return name```
I changed to Optional, still same error.

<@UNZB4NW3S>: Do you know what could be the issue here? I see a UT for this feature: <https://github.com/flyteorg/flytekit/blob/master/tests/flytekit/unit/core/test_workflows.py#L518>.

<@U07R0ED4PK8> sorry if this is a naive question but, what's the use case fro writing that task considering Flyte already can send Slack notifications on Failure? Is it because the content of the notification is not informative enough or?

<@U04H6UUE78B>: That's correct. Apart from sending informative notifications, we may want not to send the notification  based on the certain error message.

<@U07R0ED4PK8> we today do not support sending the error in the back. I think this is a small change, but at the moment not prioritized

btw, we are adding support for `webhook` notifications as a task

so you will be able to add a task to send notifications anywhere