Task 2.0a of the safe-shutdown drain-coordination plan. Widens the dashboard
auth framework GENERICALLY to support non-interactive (service-to-service)
bearer-token auth, mirroring the existing supports_password precedent. This is
a reusable capability — any future machine-credential provider plugs in without
core changes (decisions.md Q-C). The drain bearer-secret plugin (Task 2.0b) is
the first consumer, not the definition.
- base.py: add TokenPrincipal dataclass (the token analog of Session) +
supports_token capability flag + verify_token() on the ABC (default raises
NotImplementedError so a misconfigured provider fails loud). Contract mirrors
verify_session stacking: return None for unrecognised tokens (never raise),
raise ProviderError only on a genuine backing-store outage.
- registry.py: list_token_providers() — the supports_token subset, in
registration order. Empty when none registered (token routes fail closed).
- token_auth.py (new): route-agnostic seam. Routes opt in via
register_token_route(exact path); token_auth_middleware owns the auth
decision for those routes only — authenticate via stacked providers, attach
request.state.token_principal + token_authenticated, pass through. 401 on
missing/unrecognised token, 503 when a provider was unreachable, untouched
passthrough for non-token routes. Fails closed (never open).
- web_server.py: install the seam OUTERMOST (registered last → runs first).
Both downstream gates (legacy auth_middleware + gated_auth_middleware) honour
request.state.token_authenticated and skip enforcement, so a token-authed
service request is never bounced to /login.
- audit.py: TOKEN_AUTH_SUCCESS / TOKEN_AUTH_FAILURE events.
Tests: tests/hermes_cli/test_dashboard_token_auth.py — ABC flag default,
verify_token NotImplementedError, registry filter, bearer extraction
(case-insensitive scheme, malformed/non-bearer → ""), provider stacking
(first-match-wins, unreachable-remembered, unreachable-then-valid, buggy
provider doesn't crash the gate), and the seam's passthrough/401/503/
fail-closed behaviour. 29 new tests; full dashboard-auth suite 169 passed.
Intentionally deferred:
- The concrete shared-bearer-secret provider plugin — Task 2.0b.
- The begin/cancel-drain endpoint that registers itself as a token route —
Task 2.1.
Build status: dashboard-auth + plugin-hook suites green.
