kaas (broker binary)

The broker entrypoint: dispatcher registration, env wiring, the cluster runtime, and the graceful SIGTERM drain.

bins/kaas is deliberately thin on logic and thick on wiring — it's where every seam the library crates expose gets a production implementation plugged in.

main.rs: parses KAAS_LISTENERS (default: one plain listener on 0.0.0.0:9092), selects storage (KAAS_DATA_DIR set → disk engine; unset → in-memory dev mode), builds the per-listener auth engines and the cluster-wide authorizer/quota checker, registers every handler with the dispatcher, spawns the kube topic watch (in cluster mode), starts /healthz//readyz, and owns the graceful SIGTERM drain — relinquish every open partition (persisting manifests + producer snapshots, closing FDs), then flush remaining manifests as defence-in-depth (file-handle ownership).

cluster.rs: the cluster runtime — Lease election glue, heartbeat client/server wiring, broker-set watcher (2 s alive-set poll), topic-change notifier, the assignment loop when this broker is controller, the fence/marker watchers, the txn timeout reaper, and the assignment-source hot-swap (the boot-time always-true stub replaced by the real Coordinator-backed source once the runtime is up — the gh #92 dance described in Consumer-group coordination).

Mode selection: MY_POD_NAME set → cluster mode; unset → dev mode (no cluster runtime, local-lease "I lead everything", in-memory storage).

Integration tests live in bins/kaas/tests/ — smoke.rs, auth_smoke.rs, byte_opacity.rs, cluster_bringup.rs, cluster_smoke.rs, eos_v2.rs — the suites the verification story leans on.

Start reading at main.rs top to bottom — it reads as a map of the whole system.