"""Abstract base + dataclasses + exceptions for dashboard auth providers.""" from __future__ import annotations from abc import ABC, abstractmethod from dataclasses import dataclass from typing import Optional @dataclass(frozen=True) class Session: """A verified identity. Returned by ``complete_login`` and ``verify_session``. All fields are mandatory. Providers that don't have a concept of orgs should set ``org_id`` to an empty string. ``access_token`` and ``refresh_token`` are opaque to Hermes — provider-specific. """ user_id: str email: str display_name: str org_id: str provider: str expires_at: int # unix seconds; the access_token's exp claim access_token: str refresh_token: str @dataclass(frozen=True) class TokenPrincipal: """A verified non-interactive (service-to-service) caller. The token analog of :class:`Session`. Where a ``Session`` represents an interactive human identity behind a session cookie, a ``TokenPrincipal`` represents a machine/service caller that authenticated by presenting a bearer token in the ``Authorization`` request header on a single request — no login, no cookie, no refresh. Returned by :meth:`DashboardAuthProvider.verify_token` and attached to ``request.state.token_principal`` by the token-auth middleware seam so a route handler can see *who* called it. Fields: * ``principal`` — stable identifier for the caller (e.g. the provider name, a service account id, or an agent id). Opaque to the seam. * ``provider`` — the ``name`` of the provider that verified the token. * ``scopes`` — capability strings this principal is authorised for. Empty tuple means "unscoped" (the provider vouches for the caller but attaches no capability list); a route MAY enforce a required scope. """ principal: str provider: str scopes: tuple[str, ...] = () @dataclass(frozen=True) class LoginStart: """First leg of the OAuth round trip. ``redirect_url`` is the URL the browser must navigate to (e.g. the Portal's ``/oauth/authorize``). ``cookie_payload`` is a dict of cookie name → serialised value that the auth route will ``Set-Cookie`` on the response. Used for PKCE state, CSRF nonces, etc. Cookies set here MUST be HttpOnly + Secure (when over HTTPS) + SameSite=Lax with a TTL ≤ 10 minutes (the login lifetime). """ redirect_url: str cookie_payload: dict[str, str] class ProviderError(Exception): """IDP unreachable, network error, or other transient failure. Middleware translates this to HTTP 503. """ class InvalidCodeError(Exception): """The OAuth callback ``code`` / ``state`` failed validation. Middleware translates this to HTTP 400. """ class InvalidCredentialsError(Exception): """A username/password pair was rejected by a password provider. Raised by :meth:`DashboardAuthProvider.complete_password_login`. The ``/auth/password-login`` route translates this to HTTP 401 with a deliberately generic detail (never distinguishing "unknown user" from "wrong password") so the endpoint can't be used as a username oracle. """ class RefreshExpiredError(Exception): """The refresh token is dead. Middleware clears cookies and forces re-login (302 → ``/login``). """ class DashboardAuthProvider(ABC): """Protocol every dashboard-auth provider plugin implements. Lifecycle: 1. ``start_login`` — user clicks "Log in with X" on the login page. Provider returns a redirect URL and any PKCE/CSRF state to stash in short-lived cookies. 2. Browser bounces through the OAuth IDP and lands at /auth/callback. 3. ``complete_login`` — exchange the code + verifier for a Session. 4. ``verify_session`` — called on every request to validate the access token in the cookie. Returns ``None`` if the token is expired or invalid (middleware then triggers refresh or logout). 5. ``refresh_session`` — called when the access token is near expiry. Returns a new Session with rotated tokens. 6. ``revoke_session`` — called on /auth/logout. Best-effort. Failure semantics: * ``start_login`` may raise ``ProviderError`` if the IDP is unreachable. * ``complete_login`` raises ``InvalidCodeError`` on bad code/state; ``ProviderError`` if the IDP is unreachable. * ``verify_session`` returns ``None`` on expiry / unknown token; raises ``ProviderError`` if the IDP is unreachable. Middleware treats expiry and unreachable differently (expiry → refresh; unreachable → 503). * ``refresh_session`` raises ``RefreshExpiredError`` when the refresh token is also invalid; middleware then forces re-login. Raises ``ProviderError`` on network failure. * ``revoke_session`` is best-effort and must not raise. Subclasses MUST set ``name`` (lowercase identifier, stable forever) and ``display_name`` (user-facing label on the login page). Password (non-redirect) providers: A provider that authenticates with a username + password instead of an OAuth redirect sets ``supports_password = True`` and implements ``complete_password_login``. The login page then renders a credential form (POSTing to ``/auth/password-login``) instead of a "Log in with X" redirect button. Everything downstream of login — ``verify_session`` / ``refresh_session`` / ``revoke_session``, the session cookies, the WS-ticket mint — is identical to the OAuth path, because a password session is just a :class:`Session` with provider-minted opaque tokens. The OAuth methods (``start_login`` / ``complete_login``) remain abstract; a pure-password provider that will never be reached via the redirect flow may implement them as stubs that raise ``NotImplementedError``. """ name: str = "" display_name: str = "" # When True, this provider authenticates via username + password # (``complete_password_login``) rather than (or in addition to) the # OAuth redirect flow. The login page renders a credential form for # such providers; the ``/auth/password-login`` route dispatches to # ``complete_password_login``. OAuth-only providers leave this False # and are completely unaffected. supports_password: bool = False # When True, this provider can verify a non-interactive bearer token # (``verify_token``) presented on a single request by a service-to-service # caller — no login, no cookie, no refresh. This is the generic # API-token capability flag, mirroring ``supports_password``: a route # opts into token auth (see ``token_auth`` middleware seam) and the # gate consults every ``supports_token`` provider in turn until one # recognises the token. OAuth/password providers leave this False and # are completely unaffected. The drain bearer-secret plugin is the # first consumer, but the capability is deliberately generic so any # future machine-credential provider drops in without core changes. supports_token: bool = False # When True, this provider does the interactive cookie-session flow (login, # verify, refresh). The login page, /auth/login, and the gate's # verify/refresh loops consult only supports_session providers, so a # token-only credential (e.g. drain) is never offered a login. Mirrors # supports_token. supports_session: bool = True @abstractmethod def start_login(self, *, redirect_uri: str) -> LoginStart: ... @abstractmethod def complete_login( self, *, code: str, state: str, code_verifier: str, redirect_uri: str, ) -> Session: ... @abstractmethod def verify_session(self, *, access_token: str) -> Optional[Session]: ... @abstractmethod def refresh_session(self, *, refresh_token: str) -> Session: ... @abstractmethod def revoke_session(self, *, refresh_token: str) -> None: ... def complete_password_login( self, *, username: str, password: str ) -> "Session": """Verify a username/password pair and mint a :class:`Session`. Only called when ``supports_password`` is True (the ``/auth/password-login`` route guards on the flag). The default raises ``NotImplementedError`` so an OAuth-only provider that forgets to set the flag fails loudly rather than silently accepting credentials. The returned ``Session`` carries provider-minted opaque ``access_token`` / ``refresh_token`` exactly like the OAuth path, so all downstream session handling (cookies, verify, refresh, ws-tickets, logout) is identical. Failure semantics: * ``InvalidCredentialsError`` — username/password rejected. The route surfaces a generic 401 (no user-vs-password distinction). Implementations SHOULD spend constant time on unknown users (dummy hash verify) to avoid a timing oracle. * ``ProviderError`` — the backing credential store is unreachable (LDAP/DB down); the route surfaces 503. """ raise NotImplementedError( f"{type(self).__name__} does not support password login " "(set supports_password = True and override " "complete_password_login)" ) def verify_token(self, *, token: str) -> "Optional[TokenPrincipal]": """Verify a non-interactive bearer token; return its principal. The token analog of ``verify_session``. Only consulted when ``supports_token`` is True. Called by the ``token_auth`` middleware seam for every request to a token-authable route, in registration order, until one provider returns a non-None principal. Contract (mirrors ``verify_session`` stacking semantics): * Return a :class:`TokenPrincipal` if this provider recognises and accepts the token. * Return ``None`` for a token this provider does NOT recognise — never raise, so the seam can fall through to the next provider. A malformed/expired/wrong token is "not recognised" → ``None``. * Raise ``ProviderError`` ONLY for a genuine backing-store outage (the provider can neither confirm nor deny). The seam treats this like ``verify_session``: remember it, keep trying other providers, and surface 503 only if NO provider accepts the token AND at least one was unreachable. Implementations MUST use a constant-time comparison (``hmac.compare_digest``) when matching a shared secret so the endpoint isn't a timing oracle. The default raises ``NotImplementedError`` so a provider that sets ``supports_token`` but forgets to implement this fails loudly rather than silently accepting every caller. """ raise NotImplementedError( f"{type(self).__name__} does not support token auth " "(set supports_token = True and override verify_token)" ) def assert_protocol_compliance(cls: type) -> None: """Raise ``TypeError`` if ``cls`` doesn't fully implement the provider protocol. Call this in every provider plugin's unit tests:: def test_protocol_compliance(): assert_protocol_compliance(MyProvider) Returns ``None`` on success so callers can assert it explicitly. """ required_methods = ( "start_login", "complete_login", "verify_session", "refresh_session", "revoke_session", ) required_attrs = ("name", "display_name") for attr in required_attrs: val = getattr(cls, attr, "") if not val: raise TypeError( f"{cls.__name__} missing or empty attribute: {attr!r}" ) for method in required_methods: if not callable(getattr(cls, method, None)): raise TypeError(f"{cls.__name__} missing method: {method}") # Also catch the ABC-not-overridden case. if getattr(cls, "__abstractmethods__", None): raise TypeError( f"{cls.__name__} has unimplemented abstract methods: " f"{sorted(cls.__abstractmethods__)}" )