@Marvin what is the simplest way to setup slack notifications on job failures?

To set up Slack notifications for job failures in Prefect, you can use state change hooks. Here is an example of how to notify a Slack channel when a flow fails: Step-by-Step Guide: 1. Create a Slack Webhook: - First, you need to create a Slack webhook and save the Webhook URL. 2. Define the Slack Notification Function: - You can use the following example function to send notifications.

from prefect import flow
from prefect.blocks.core import Block
from prefect.settings import PREFECT_API_URL

def notify_slack(flow, flow_run, state):
    slack_webhook_block = Block.load("slack-webhook/my-slack-webhook")
    slack_webhook_block.notify(
        (
            f"Your job {flow_run.name} entered {state.name} "
            f"with message:\n\n"
            f"See <https://{PREFECT_API_URL.value()}/flow-runs/"
            f"flow-run/{flow_run.id}|the flow run in the UI>\n\n"
            f"Tags: {flow_run.tags}\n\n"
            f"Scheduled start: {flow_run.expected_start_time}"
        )
    )

3. Use the Notification Hook in a Flow: - Configure the flow to use the

on_failure

hook to call the

notify_slack

function.

@flow(on_failure=[notify_slack], retries=1)
def failing_flow():
    raise ValueError("oops!")

if __name__ == "__main__":
    failing_flow()

This example configures a flow to send a Slack notification if the flow enters a failed state. References: - State Change Hooks Documentation: https://docs.prefect.io/latest/guides/state-change-hooks/ - Slack Integration Documentation: https://docs.prefect.io/latest/integrations/prefect-slack/ For more detailed information, refer to the provided links.

@Marvin where in Prefect cloud do I add the slack credentials?

To add Slack credentials in Prefect Cloud, follow these steps: 1. Create a Slack Webhook or OAuth Token: - Create a Slack app and get either a Webhook URL or a Bot User OAuth token from Slack's app setup. 2. Use Prefect's Slack Blocks: - Prefect provides specific blocks to store and utilize Slack credentials. These are

SlackCredentials

for OAuth tokens and

SlackWebhook

for Webhook URLs. 3. Store Credentials in Prefect Cloud: - You can store these credentials using the Prefect UI. Step-by-Step Instructions: - For Slack Webhook: 1. Go to the Prefect Cloud UI. 2. Navigate to Blocks. 3. Create a new block and select SlackWebhook. 4. Set the block name and input the Webhook URL. - For Slack OAuth Token: 1. Go to the Prefect Cloud UI. 2. Navigate to Blocks. 3. Create a new block and select SlackCredentials. 4. Set the block name and input the Bot User OAuth token. Example Code: To load and use these credentials in your flow, you can use the following example:

from prefect import flow
from prefect.blocks.core import Block
from prefect.settings import PREFECT_API_URL

def notify_slack(flow, flow_run, state):
    slack_webhook_block = Block.load("slack-webhook/my-slack-webhook")
    slack_webhook_block.notify(
        (
            f"Your job {flow_run.name} entered {state.name} "
            f"with message:\n\n"
            f"See <https://{PREFECT_API_URL.value()}/flow-runs/"
            f"flow-run/{flow_run.id}|the flow run in the UI>\n\n"
            f"Tags: {flow_run.tags}\n\n"
            f"Scheduled start: {flow_run.expected_start_time}"
        )
    )

@flow(on_failure=[notify_slack], retries=1)
def failing_flow():
    raise ValueError("oops!")

if __name__ == "__main__":
    failing_flow()

References: - Prefect Slack Integration: https://docs.prefect.io/latest/integrations/prefect-slack/ - Slack Credentials Documentation: https://docs.prefect.io/latest/integrations/prefect-slack/credentials/ These steps should help you set up Slack notifications for your job failures.