The k3s OIDC discovery + JWKS endpoints require an AUTHENTICATED request
(anonymous -> 401; anonymous-auth is off on the cluster) and are served over the
cluster CA. A bare http.DefaultClient (correct for public Authentik) cannot
reach them, so multi-issuer alone (v0.4.0) could not actually validate k8s SA
tokens in-cluster.
Add IssuerConfig.HTTPClient: when set, it fetches THAT issuer's discovery + JWKS
(threaded into discoverJWKSURI and jwk.Cache.Register via jwk.WithHTTPClient).
The k8s-issuer consumer supplies a client that trusts the cluster CA
(/var/run/secrets/kubernetes.io/serviceaccount/ca.crt) and carries the server
pod's SA bearer. nil keeps http.DefaultClient (Authentik/public, unchanged).
Test: an auth-gated in-process issuer — unauthenticated fetch fails, a client
carrying the credential builds + validates a token. Empirically grounded in the
k3s 401 finding during the ADR-0011 in-cluster PoC.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
JWTValidator trusted a single issuer (iss matched exactly against DEX_ISSUER_URL),
which is why every in-cluster caller fell back to a static bearer. Add support
for a LIST of trusted issuers so one MCP server can accept Authentik JWTs
(interactive/web) AND k3s cluster ServiceAccount tokens (in-cluster, audience-
bound, kubelet-rotated) at once — the enabler for ADR-0011.
- Add IssuerConfig{IssuerURL, Audience} + NewMultiJWTValidator([]IssuerConfig).
- Refactor JWTValidator to hold []issuerEntry + a shared jwk.Cache; Validate
tries each trusted issuer, returns the subject on first success. All-issuers-
JWKS-unreachable -> ErrUnavailable (503); any definitive reject -> 401.
- NewJWTValidator (single issuer) and BearerMiddleware signatures UNCHANGED —
existing consumers (gitea-mcp, ingestion) compile and behave identically.
- Add auth/jwt_test.go: an in-process OIDC issuer harness (discovery + JWKS +
token minting) — the chassis previously had NO happy-path JWT test. Covers
accept-either-trusted-issuer, reject-untrusted (401 not 503), per-issuer
audience enforcement, single-issuer backward compat.
Proven viable by the ADR-0011 live-cluster spike (k3s OIDC/JWKS validates a
projected SA token). Follow-up: wire gitea-mcp/brain-mcp/ingestion to also trust
the k3s issuer + mount an audience-scoped projected SA token on one pod.
Refs infra ADR-0011; supersedes the sidecar in infra#183. (Tracked as
hyperguild#77, which was misfiled — the chassis is this repo, not hyperguild.)
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
mathiasandClaude Opus 4.8