Slack connection

Send messages / alerts to Slack from a task via a managed Leoflow Connection. Two conn types ship: slack (Slack API, a bot token) and slackwebhook (an Incoming Webhook URL). Use slack for rich API calls, slackwebhook for a fire-and-forget message to one channel.

Declare the provider

# leoflow.yaml
dag_id: slack_alert
connectors:
  - slack

Fields the UI asks for

slack (API):

slackwebhook: put the webhook path in the connection (host hooks.slack.com, password = the T00/B00/XXXX token segment), or the full URL in Extra {"webhook_token": "…"}.

The token round-trip (reserved characters included) is pinned by TestSlackConnectionURIShapeIntegration.

Example DAG (copy-paste)

Docs-only recipe (needs a Slack workspace + bot token). The hook is imported inside the task.

# dag.py
from __future__ import annotations

from airflow.sdk import DAG, task


@task
def notify() -> None:
    from airflow.providers.slack.hooks.slack import SlackHook

    hook = SlackHook(slack_conn_id="slack_default")
    print("notify: posting message via SlackHook(slack_default)")
    hook.call(
        "chat.postMessage",
        json={"channel": "#data-alerts", "text": "Leoflow run finished ✅"},
    )


with DAG("slack_alert", schedule=None, catchup=False, tags=["example"]):
    notify()

# leoflow.yaml
schema_version: "1.0"
dag_id: slack_alert
description: Post a message to Slack via SlackHook.
owner: examples
tags:
  - example
python_version: "3.11"
connectors:
  - slack

Run it

1. Create a Slack app with a bot token (chat:write scope), invite the bot to the channel.
2. Admin → Connections → +, type slack, paste the token in Password.
3. leoflow lite path/to/this/dag → trigger slack_alert → check the channel.

Security notes

• The bot token is a secret — it is encrypted at rest and never echoed back by the form. Scope it to the minimum (chat:write).
• Never print() the URI — it carries the token.

Related

• docs/connections/index.md — Installing a connector’s provider.
• ADR 0019 / 0021 — secret encryption + agent delivery.