* Return None instead of erroring on drain login failure
* Fix login on drain
* Remove login for drained endpoints flow and clean the code
* chore: drop unrelated credits changes from this PR
* Remove extra comments that were not really necessary
Task 2.0b: the concrete shared-bearer-secret auth provider, the FIRST consumer
of the generic token-auth capability (Task 2.0a). Implements decisions.md Q-A.
plugins/dashboard_auth/drain/ (bundled, discovered like dashboard_auth/basic):
- DrainSecretProvider: non-interactive provider, supports_token=True. Verifies
an inbound Authorization bearer token against a per-agent shared secret with
hmac.compare_digest (constant-time, no timing oracle) and, on a match,
vouches for the caller as the "drain-control" principal scoped to "drain".
The five interactive ABC methods raise NotImplementedError; verify_session
returns None (stacks harmlessly in the cookie-verify loop).
- assess_secret_strength(): fail-closed entropy gate. Rejects secrets shorter
than 43 url-safe-b64 chars (~256 bits), with < 16 distinct characters, or
below 128 bits Shannon entropy — so a weak/structured/repeated secret can
never be silently accepted. Enforced both at register() (friendly skip
reason) and in __init__ (raises — defence in depth).
- register(ctx): no-op + skip reason when HERMES_DASHBOARD_DRAIN_SECRET is
unset; rejects a weak secret fail-closed (drain endpoint stays gated). On a
strong secret, registers the provider AND opts /api/gateway/drain into the
generic token-auth seam via register_token_route().
Config: the secret is a CREDENTIAL → carried via HERMES_DASHBOARD_DRAIN_SECRET
(per-agent, provisioned by NAS at deploy). Behavioural knobs only
(dashboard.drain_auth.{scope,min_secret_chars}) live in config.yaml — added to
DEFAULT_CONFIG with the .env-is-for-secrets rationale documented inline.
Tests: tests/plugins/dashboard_auth/test_drain_provider.py — entropy gate
(strong pass; empty/short/repeated/few-distinct/custom-min reject), verify_token
(match → scoped principal, wrong/empty → None, custom scope), protocol
compliance, interactive-methods-raise, and register() (skip-no-secret,
fail-closed-weak-secret, strong-env-secret registers + route opt-in, config
scope + min_secret_chars). 21 new tests; drain + token-auth suites 44 passed.
Verified the plugin is discovered as dashboard_auth/drain alongside basic/nous.
Intentionally deferred:
- The begin/cancel-drain endpoint handler itself — Task 2.1.
- The dashboard→gateway control channel — Task 2.2.
Build status: dashboard-auth + drain-plugin suites green.
