flyteplugins-slack

Receive Slack webhooks in Flyte: Events API callbacks, interactivity payloads (Block Kit actions, shortcuts, modals), and slash commands — one route serves all three.

pip install "flyteplugins-slack[app]"

Using it

Hand a SlackProvider() to a WebhookAppEnvironment and register handlers with the typed constants in events:

import flyte
from flyte.extras.webhooks import WebhookAppEnvironment, WebhookEvent, run_once
from flyteplugins.slack import SlackProvider, events

# SlackProvider.default_secret_env is mounted for you.
app_env = WebhookAppEnvironment(name="slack-webhooks", providers=[SlackProvider()])


@app_env.on_event(events.AppMention.ANY)
async def handle(event: WebhookEvent):
    import flyte.remote as remote

    task = remote.Task.get(name="my-env.my_task", auto_version="latest")
    result = await run_once.aio(task, key=event.dedupe_key(), resource=event.resource_id)
    if not result.created:
        return {"skipped": result.run.name, "url": result.run.url}
    return {"run": result.run.name}


flyte.serve(app_env)

Handlers must await run_once.aio(...). The blocking form stalls the app's event loop, and Slack times deliveries out in seconds.

One app can serve several products at once — hand it one provider per product.

Try it

Two examples, each runnable two ways — --local needs no Slack account:

python examples/slack_webhooks.py --local      # Events API: replay a real sample delivery
python examples/slack_interactions.py --local  # buttons + slash commands, signed and replayed
python examples/slack_webhooks.py              # deploy the receiver to Flyte

--local posts signed deliveries through the app with FastAPI's test client, so you see each one verified, normalized, and dispatched — plus an unsigned one refused with a 401. slack_webhooks.py covers the Events API and stable dedupe keys; slack_interactions.py covers a Block Kit button (block_actions.<action_id>), a slash command (command.<name>), and the ssl_check probe.

Setup

1. Store the secret and mount it on the app:

   flyte create secret SLACK_SIGNING_SECRET --value <secret>
   

2. Point Slack at <app-url>/webhook/slack — the same URL in every place your app uses, at api.slack.com/apps:
   • Event Subscriptions → Request URL, then subscribe to bot events;
   • Interactivity & Shortcuts → Request URL, for Block Kit buttons, shortcuts, and modals;
   • Slash Commands → each command's Request URL.

Slack POSTs a url_verification challenge before events flow and an ssl_check probe to interactivity and slash-command URLs; both are answered automatically, so the Request URL fields verify themselves.

Verification: HMAC-SHA256 over v0:{timestamp}:{body}, with a five-minute replay window (X-Slack-Signature). The same scheme signs all three delivery shapes.

Messages are keyed per message, so each one launches its own run. To collapse a whole thread onto one run, pass event.payload["event"]["thread_ts"] as your own key.

Interactivity and slash commands

An interaction's action is its action_id (or callback_id), and a slash command's is its name. Those identifiers are your app's own vocabulary, so no constant can spell them — the action= kwarg carries your half of the name, the constant carries Slack's:

@app_env.on_event(events.Interaction.BLOCK_ACTIONS, action="approve_reply")
async def approve(event: WebhookEvent):
    # event.payload is Slack's full JSON: actions, container, message, response_url.
    channel, ts = event.payload["container"]["channel_id"], event.payload["container"]["message_ts"]
    ...


@app_env.on_event(events.Command, action="/deploy")  # the leading / is dropped for you
async def deploy(event: WebhookEvent):
    text = event.payload["text"]
    ...

Without action=, events.Interaction.BLOCK_ACTIONS and events.Command.ANY match their whole categories. (The equivalent raw strings — "block_actions.approve_reply", "command.deploy" — still work.)

event.payload is Slack's JSON verbatim, typed as dict[str, Any]. For autocomplete, take a typed view of it — a cast, not a copy or a validation:

payload = payloads.block_actions(event)  # payload["actions"][0]["value"] completes
payload = payloads.command(event)  # payload["text"], payload["channel_id"], ...

Slack shows the user an error unless the delivery is answered within 3 seconds, so handlers for these must do nothing slower than run_once.aio — post progress back via slack_sdk from the launched task.

Event constants

events spells every event this plugin can dispatch, as str enums grouped by event type, so a typo fails at import rather than by silently never matching. Raw strings still work, for events the constants do not cover yet.

Sending messages

Receiving is the webhook app's job; sending is your task's. notify covers the sends every integration hand-rolls:

from flyteplugins.slack import notify

ts = await notify.post("C0DEPLOYS", "deploy started", thread_ts=thread_ts)
await notify.update("C0DEPLOYS", ts, "deploy finished")

post/update/delete read the bot token from SLACK_BOT_TOKEN — mount it with flyte.Secret("SLACK_BOT_TOKEN"). That is the xoxb- credential from OAuth & Permissions (scope chat:write), not the signing secret.

notify.respond(response_url, ...) needs no token: every interaction and slash command carries a response_url (30 minutes, five uses), so a launched task can answer the click that launched it with zero credential setup.

notify also ships a deployable environment: deploy notify.env once, and only it holds the bot token — every other run posts through flyte.run(notify.send, channel=..., text=...).

Approvals

approval turns "deploy to prod?" into one await, pairing the webhook receiver with a core flyte.new_condition:

# in a task
from flyteplugins.slack import approval

decision = await approval.request.aio("C0DEPLOYS", "Deploy release-42 to prod?")

# in the webhook app
approval.register(app_env)

request posts Approve/Reject buttons and parks the run on a condition. The clicked button carries the run, action, and condition names in its value, so register's handler looks the condition up with flyte.remote.Condition.get and signals it — no configuration on the app side — then replaces the buttons with a "approve — decided by @who" line so nobody clicks twice.

Because it is an ordinary condition, the same prompt is answerable from the Flyte UI, so an approval nobody clicks in Slack is never stuck. Pass timeout= to bound the wait (flyte.errors.ConditionTimedoutError on expiry).

What this plugin does not do

Everything else in the Slack Web API — reading history, opening modals, managing channels. Use slack_sdk from your tasks for that; notify covers only the sends, and the receiver owns only the part that is Flyte's: authenticating an inbound delivery and turning it into a run.