@Marvin can you share an example of code to notify in slack when prefect 2 task fails?

Ah, the futility of existence. It appears I'm unable to access the Prefect documentation at the moment. However, I can still provide you with a general example of how to notify Slack when a Prefect task fails. You can use Prefect's

slack_notifier

function in combination with the

on_failure

event handler. Here's a rough example:

python
from prefect import task, Flow
from prefect.utilities.notifications import slack_notifier

@task
def failing_task():
    raise ValueError("This task is designed to fail.")

@slack_notifier.on_failure
def notify_slack(task, state, **kwargs):
    # Your code to send a message to Slack goes here.
    # You can use the `state` parameter to get information about the failed task.
    pass

with Flow("Slack_Notification_Example") as flow:
    task_1 = failing_task()

task_1.set_task_run_states_handlers([notify_slack])

flow.run()

In the

notify_slack

function, you'll need to implement the actual Slack message sending using the Slack API or a library like

slackclient

. Don't forget to include your Slack API token and the channel where you want to send the notifications. Please note that this is a general example, and you might need to adapt it to your specific use case. If you need more information, I recommend checking the Prefect documentation once it's available again. Good luck, and may your tasks fail gracefully.

@Marvin can you provide example using prefect 2?

Oh, the cruel irony of existence. It seems I'm unable to access the Prefect documentation at the moment. However, I can still provide you with a general example of how to notify Slack when a Prefect 2 task fails. You can use Prefect's

slack_notifier

function in combination with the

on_failure

event handler. Here's a rough example:

python
from prefect import task, Flow
from prefect.utilities.notifications import slack_notifier

@task
def failing_task():
    raise ValueError("This task is designed to fail.")

@slack_notifier.on_failure
def notify_slack(task, state, **kwargs):
    # Your code to send a message to Slack goes here.
    # You can use the `state` parameter to get information about the failed task.
    pass

with Flow("Slack_Notification_Example") as flow:
    task_1 = failing_task()

task_1.set_task_run_states_handlers([notify_slack])

flow.run()

In the

notify_slack

function, you'll need to implement the actual Slack message sending using the Slack API or a library like

slackclient

. Don't forget to include your Slack API token and the channel where you want to send the notifications. Please note that this is a general example, and you might need to adapt it to your specific use case. If you need more information, I recommend checking the Prefect documentation once it's available again. Good luck, and may your tasks fail gracefully.

ah shoot, looks like marvin needs a knowledge refresh, he isnt pulling docs right now, will fix i think you’re looking for automations

Thanks @Nate. One last question, I was trying to migrate prefect 1 flow task where slack notifier was configured in the code. But configuring automation via prefect 2 UI would help to get rid of slack notifier configuration via code as we did in prefect 1? Right?

yes! automations for alerts would bypass the need for defining alerts in code, however if you wanted to continue to do so, you could use the slack webhook notification block

Gotcha. Thank you for prompt reply! 🙂

@Marvin please look up slack notification blocks and automations to explain how we can be notified when a task fails

Ah, the sweet sound of Slack notifications. In Prefect, you can set up notifications to be alerted when a task fails. Prefect supports sending notifications via various channels, including Slack messages to a channel. To set up a Slack notification for task failures, follow these steps: 1. Go to the Notifications page in Prefect. 2. Select Create Notification or the + button. 3. Choose which run states should trigger a notification (in this case, the "failed" state). 4. Add tags to filter which flow runs are covered by the notification (if needed). 5. Select Slack as the notification service. 6. Provide the webhook credentials for your Slack and the channel to which the message should be sent. For example, to get a Slack message if a flow with a "daily-etl" tag fails, the notification will read:

If a run of any flow with "daily-etl" tag enters a "failed" state, send a notification to "my-slack-webhook"

When the conditions of the notification are triggered, you'll receive a message like:

The "fuzzy-leopard" run of the "daily-etl" flow entered a "failed" state at "22-06-27 162137 EST."

You can pause, edit, or delete any configured notification on the Notifications page source. Now you can enjoy the symphony of Slack notifications, as if you didn't have enough distractions already.

@Marvin, when I do what you wrote to add a new automation in prefect Cloud (with Kubernetes agent) to send a Slack notification when particular flow failes - I see in Event Feed that "Automation action failed". In payload I see the reason:

The notification block was invalid: KeyError(\"No class found for dispatch key 'slack-incoming-webhook' in registry for type 'Block'.\")

What am I doing wrong?

I apologize for the confusion earlier. It appears that the information I provided was not accurate for Prefect Cloud with Kubernetes agent. In Prefect Cloud, you should use the Automations feature to set up notifications related to flow run state changes and work queue health. Here's how to set up a Slack notification using Automations in Prefect Cloud: 1. Go to the Automations page in Prefect Cloud. 2. Click on Create Automation. 3. Choose the trigger event, such as "Flow Run State Change". 4. Configure the event filter, for example, select the "Failed" state. 5. Add an action, such as "Send a Slack message". 6. Provide the webhook URL for your Slack workspace and the channel to which the message should be sent. Once you've set up the automation, you should receive Slack notifications when the specified event occurs, such as a flow run entering the "Failed" state. For more information, please refer to the Prefect Cloud documentation. I hope this clears up the confusion. Remember, even robots make mistakes sometimes.