Module webhooks 

Webhooks: the server says what it noticed to where a manager already is.

Alerts made the server notice things on its own (ADR 0018), and then wait on a dashboard for somebody to open it. This module takes the same record outward - to a Slack or Mattermost channel, a Telegram chat, or a system of the operator’s own - without replacing it: delivery is added to the record, and the row an alert wrote is what gets sent.

Three decisions shape everything here (ADR 0019):

• Destinations live in the environment, not in the database. A hook URL and a bot token are working credentials to post as somebody, and the database is what kasl-server backup writes to a file. They sit next to the database password, in KASL_WEBHOOK_<NAME>, and everything else - the delivery log, the screen, the privacy manifest - knows a destination by its name alone.
• An event is queued in the transaction that made it true. The alert row and the delivery row commit together, or neither does. An in-memory channel loses what was queued on every restart, and “the server restarted at the moment the agent died” is exactly the night nobody hears about.
• Delivery is at least once, in order, per destination. The dispatcher retries with growing gaps and gives up in writing after about a day; a destination that is failing holds its own later events back rather than letting “resolved” overtake “raised” in somebody’s channel. Every event carries an id a receiver can deduplicate on, because a request that timed out may still have arrived.

Structs

AlertPayload

An alert as it fired. The figures are the ones it fired on, never re-derived: a message already read must not change under its reader (ADR 0018).

DayPayload

A day as it arrived finished.

DeliveryView

One delivery, newest first on the screen.

Destination

One place events are sent.

DestinationView

One destination, as the screen shows it.

Dispatched

What one tick did.

Event

One thing that happened, as every destination is told it.

Overview

The screen: where events go, and how the last ones went.

Person

The person an event is about.

Webhooks

Every destination this installation sends to, and where its screens live.

Enums

EventKind

What happened. Mirrors the webhook_event enum.

Kind

What a destination speaks.

Constants

PAYLOAD_VERSION

The payload’s shape. A receiver of the json kind reads this first; a change to what a field means is a new number, not a quiet edit.

PREFIX

The prefix every destination’s variable starts with.

Functions

client

The HTTP client every delivery goes through.

dispatch_due

Sends everything that is due, once.

enqueue

Queues an event for every destination that hears it and may hear about this person. Returns how many rows were written.

hmac_sha256

HMAC-SHA256 of message under key (RFC 2104).

overview

Answers the destinations and the recent deliveries. Administrators only: the log names people and the screen names where their alerts go.

person

Reads who an event is about.

run_dispatcher

Runs the dispatcher for as long as the server runs.

send_test

Queues a test message for one destination. Administrators only.

signature

The X-Kasl-Signature header’s value for a body sent at timestamp (seconds since the epoch).