#4573 [Core feature] Add support try and except in the workflow Issue created by pingsutw ### Motivation: Why do you think this is important? It's follow-up to these failure node PRs • flyteorg/flytekit#840 • #4308 People might want to pass a specific task output to a failure node. To support that flytekit need to support try and except first, so users are be able to pass a promise to failure node. ### Goal: What should the final outcome look like, ideally? @workflow def wf(name: str = "my_cluster"): id = create_cluster(name=name) try: t = t1(a=1, b="2") except: d = delete_cluster(id=id) # failure node c >> t >> d ### Describe alternatives you've considered For now, failure node's input is same as workflow inputs. @task(container_image=image_spec) def clean_up(name: str): print(f"Deleting cluster {name}") @workflow(on_failure=clean_up) def wf2(name: str = "kevin"): c = create_cluster(name=name) t = t1(a=1, b="2") d = delete_cluster(name=name) c >> t >> d ### Propose: Link/Inline OR Additional context No response ### Are you sure this issue hasn't been raised already? • Yes ### Have you read the Code of Conduct? • Yes flyteorg/flyte