Previously the HTTP response status was only logged, so retries never
triggered for failing webhooks and downstream fan-out bugs (#2569) were
impossible to exercise via tests. Returning an error lets the watermill
retry middleware do its job.
Block webhook requests to non-globally-routable IP addresses by default.
Uses net.Dialer.Control hook to validate resolved IPs against IANA
Special Purpose Registries after DNS resolution, preventing DNS rebinding.
Configurable via webhooks.allownonroutableips (default: false).
Add user_id column to webhooks table (nullable, for user-level webhooks
vs project-level). Extend webhook model, permissions, and listener to
support user-level webhooks that fire for user-directed events like
task reminders and overdue task notifications.
Add TasksOverdueEvent for dispatching overdue notifications via webhooks.
Update webhook permissions to handle both user-level and project-level
ownership. Add webhook test fixture and register webhooks table in test
fixture loader.
Fixes a bug where the webhook HTTP client was mutating `http.DefaultClient` (the global singleton), causing ALL HTTP requests in the application to use the webhook proxy. This broke OIDC authentication and other external HTTP calls when webhook proxy was configured.
Fixes#2144