When a Backstage notification is re-sent with the same scope, the
notifications backend updates the existing DB record and sets
notification.updated. Previously, the SlackNotificationProcessor always
called chat.postMessage(), creating duplicate Slack messages.
This adds database-backed scope-based update support:
- New slack_message_timestamps table to persist Slack message ts values
keyed by (scope, channel)
- After each chat.postMessage(), store the response ts in the database
- When postProcess receives a notification with updated set and a
matching stored ts, use chat.update() instead of chat.postMessage()
- Scope context is passed as parameters through the call chain to avoid
race conditions with concurrent postProcess calls
- Scheduled daily cleanup of old timestamp records (24h retention)
- New messagesUpdated metrics counter for observability
- Graceful degradation when no database is provided
- Explicitly picks only supported fields for chat.update calls
Signed-off-by: Erik Miller <erik.miller@gusto.com>
Erik Miller