@Marvin how do you tag users when using automations to send Slack notifications?

To tag users in Slack notifications when using Prefect automations, you can follow these general steps: ### 1. Setting Up Slack Webhook Firstly, ensure you have your Slack webhook URL. This can be set up in the Slack app settings and is required for sending messages to specific Slack channels. ### 2. Configuring Notification in Prefect 1. Navigating to Notifications: - Go to the Notification page on your Prefect Cloud or Prefect Server. - Select

Create Notification

or use the

+

button. 2. Setting up the Notification: - Choose which run states should trigger a notification. - Optionally, add tags to filter which flow runs are covered by the notification. - Choose to send a Slack message and provide the necessary webhook credentials for your Slack workspace. 3. Customizing the Message: - You can customize the Slack message to include the user tag. In Slack, tagging a user involves including their handle in the message. For example, to tag a user named

@username

, your message would include

Hello <@username>

. ### Example Code Snippet Below is an example Prefect automation script that sends a Slack notification and tags a specific user:

python
from prefect import task, flow
from prefect.notifications import SlackWebhook

@task
def example_task():
    return "The flow run is complete."

@flow
def example_flow():
    task_result = example_task()
    webhook = SlackWebhook(url="YOUR_SLACK_WEBHOOK_URL")
    webhook.notify(message=f"Task result: {task_result}\n\nHello <@username>, please check the task status.")

if __name__ == "__main__":
    example_flow()

### References and Useful Links - Prefect Documentation: Notifications configuration - GitHub Issue on Notifications Metadata: Better management of Notifications in Cloud 2.0 UI That should cover the basics. For more specific configurations, please refer directly to the Prefect documentation.

Hello @username

i dont think this actually works you need the user id im pretty sure

I was trying to do it by triggering slack notifications via Prefect Automations but it seems that it converts Slack tags to plain text

aha okay if you use the one from

prefect_slack

it works

In [7]: from prefect_slack import SlackWebhook
   ...: slack_webhook_block = SlackWebhook.load("pager")

In [8]: slack_webhook_block.notify("Hello from Prefect! <@U03RX2A8LK0>")

Sorry, are you saying that I'd need to do tags in Slack Pythonically rather than through the Prefect Cloud automation?

sorry, no. im saying that: •

SlackWebhook

is from

prefect_slack

• a different

SlackWebhook

is from

prefect

(the one you tried) https://github.com/search?q=repo%3APrefectHQ%2Fprefect%20SlackWebhook&type=code are currently 2 different block types, both of which you can find / create in the UI. the one from

prefect_slack

was implemented using the slack sdk, so it supports the user mentioning syntax above, whereas the apprise implementation in core doesnt going forward, i am going to remove the one from core in prefect 3.x so that its less confusing and because the one from

prefect_slack

is better

we should be using the "Slack Incoming Webhook"? the one that prints tags as plaintext was the "Slack Webhook" block type

the "Incoming Webhook" doesn't seem to successfully send notifications via an automation

can you share what went wrong?

I made a new webhook and created a Slack Incoming Webhook block with it; the automation itself is just when a flow run enters a fail state:

hmm do you have an

prefect-cloud.automation.action.failed

in your Event Feed?

oh interesting yes there is, these correspond with the times of my testing; here's the raw JSON of the failed automation event:

{
  "id": "6f45b44e-435f-4263-9441-f8ce94f8ae81",
  "account": "97028b81-bea9-458e-a561-24b4031e349c",
  "event": "prefect-cloud.automation.action.failed",
  "occurred": "2024-06-28T20:07:59.767Z",
  "payload": {
    "action_index": 0,
    "action_type": "send-notification",
    "invocation": "1719fb87-2a08-4de1-9ca3-94532f363ba0",
    "reason": "The notification block was invalid: KeyError(\"No class found for dispatch key 'slack-incoming-webhook' in registry for type 'Block'.\")"
  },
  "received": "2024-06-28T20:07:59.768Z",
  "related": [],
  "resource": {
    "prefect.resource.id": "prefect-cloud.automation.c2ec2959-fd53-49e9-90f0-28e73418bbb5",
    "prefect.resource.name": "Failure/Paused Notifications",
    "prefect-cloud.trigger-type": "event",
    "prefect-cloud.posture": "Reactive"
  },
  "workspace": "afa27e96-6a02-402f-9ad7-bffbcf577974"
}

> "The notification block was invalid: KeyError(\"No class found for dispatch key 'slack-incoming-webhook' in registry for type 'Block'.\")" okay, this looks like a bug. to me this says "Prefect Cloud doesnt have this block type registered", but we do have the

SlackWebhook

from core registered (which is why the message goes through in that case) so right now, it might not be directly possible to tag a user in your automation action with the

SlackWebhook

from

prefect

, because

apprise

is mutating that message somewhere on the way to the slack API, sorry about that I will make an issue to install the one from

prefect_slack

(that works as desired) server side so it can be used in automation actions

Thanks for this bringing this up Luke. Put your name in for the bug bounty haha

lol thanks @Nate it's not a big deal for us right now; I was just worried I was missing something obvious, but good to know!

thanks for the report and additional info!