@Marvin should i use the Email block to send email on task fail? Or should i write a function to send email on task fail hook?

To determine the best approach for sending an email when a task fails in Prefect, I'll need to confirm the specific version you're using, as Prefect 2.x and Prefect 3.x might handle blocks and hooks differently. Could you please let me know which version of Prefect you're using?

In Prefect 3.x, there are a couple of ways you can handle sending emails on task failure, and the choice depends on your preference for simplicity or customizability. 1. Using Email Blocks: Prefect provides an

EmailServerCredentials

block and an

email_send_message

function that you can use to send emails. You can define these blocks in your Prefect flow, and wrap them in an exception handling block. This approach allows you to configure your email notifications via the Prefect UI, making it more straightforward to adjust settings without changing your code. Here's a brief example:

python
   from prefect import flow
   from prefect.context import get_run_context
   from prefect_email import EmailServerCredentials, email_send_message

   def notify_exc_by_email(exc):
       context = get_run_context()
       flow_run_name = context.flow_run.name
       email_server_credentials = EmailServerCredentials.load("YOUR_BLOCK_NAME")
       email_send_message(
           email_server_credentials=email_server_credentials,
           subject=f"Flow {flow_run_name} Failed",
           msg=str(exc),
           email_to="<mailto:your_email@example.com|your_email@example.com>",
       )

2. Writing a Custom Hook: Prefect allows you to define hooks that run on specific state transitions. You can write a failure hook that sends an email when a task fails. This approach provides more control over the logic executed during the hook. For instance:

python
   from prefect import task, flow
   from prefect.states import State

   def my_failure_hook(task, task_run, state: State):
       if state.is_failed():
           # Add your email sending logic here
           print("Task failed, sending email...")

   @task(on_failure=my_failure_hook)
   def task_that_might_fail():
       # Task logic here
       pass

In conclusion, if you prefer a more integrated and less code-heavy solution, using the Prefect Email block is the way to go. If you need more control or wish to perform additional actions when a task fails, writing a custom hook could be beneficial. Here are some useful links for further reading: - Prefect Email Integration - Prefect State Management Let me know if you need any more information or assistance!