Task 3.6 of novox/hq ADR 0116. A module is still written against request,
handle, publish, subscribe, close; only what is underneath changes. main.ts
still selects the AMQP client — steps 1 to 4 leave every node on AMQP, so
this ships beside it and is selected at the rollout.
Round-tripped against a real server (test/roundtrip.mjs): a tool answered
across two connections, a throwing handler reaching the caller as an error
rather than a timeout, an event delivered once with its key, body, node and
event id intact, and an event landing under its emitter's own namespace.
Three things the compiler and the server corrected:
- the envelope's field is `key`, not `type`, and the payload is `env.body`
with metadata in headers — not the whole envelope re-encoded. An
implementation that nested the envelope would pass all its own tests and
agree with nobody, which is what the conformance suite exists to stop.
- the NATS client's TLS options are PEM strings with no verify hook, so the
AMQP client's `checkServerIdentity: () => undefined` has no equivalent.
The fingerprint check still happens and is still the guarantee, but the
bus's certificate must now carry a SAN matching the address nodes dial.
That is a constraint on the mesh's certificates, recorded where it bites.
- a durable consumer is bound, never created: a module's account cannot
reach the JetStream API, and a runtime creating its own would be a module
choosing its own delivery semantics.
The retry loop treated everything but a cert-pin mismatch as transient,
so a refused login (revoked/mis-sealed credential) or a malformed broker
URL retried for ever logging 'not reachable yet' — the silent
non-progress the fix set out to remove, and a contradiction of its own
docstring. fatalBrokerReason now classifies those three as fatal and
everything else (connection refused, timeout, DNS) as retryable, with a
unit test covering the split — the honest proof the bed cannot give,
since it only ever starts the consumer after the broker is up.
The pin case is now a typed PinMismatchError caught by instanceof, not a
prose substring a reword could silently downgrade to an infinite retry
against an impostor. Added a little jitter so modules do not stampede a
recovering broker in lockstep.
One name per thing, per the HQ glossary: the module/container/image/binary/repo
becomes mesh-controller, the seat the-controller, and the store+broker pair the
foundation (embedded base bundles, default template and example lock renamed with
their go:embed directives). No behaviour change — a pure vocabulary rename.
Claude-Session: https://claude.ai/code/session_01D6qtiYU3P9jk3pnAXyAFyx
Replies go through the RPC exchange keyed by the caller's reply-queue name, not
the default exchange — so a serving module's scoped account answers with write
on mesh.rpc alone, never the default exchange (which would let it publish into
any queue). 'mesh-tools invoke <module> <tool> [args]' is the caller's side, the
sibling of emit. Verified against a real broker: a scoped account serves its
tool and is refused another module's serve queue.
The AMQP adapter now honours the full contract: events published
persistent with metadata in headers; a durable per-consumer queue
(<node>.<module>.events) with prefetch and a dead-letter exchange
(mesh.events.dead); manual ack for at-least-once.
Failure paths, not just the happy one:
- a confirm channel, so a publish the broker never accepted fails the
emit rather than vanishing — at-least-once starts at the emitter;
- a handler that keeps failing is requeued once, then dead-lettered
(poison set aside, never looping);
- an undecodable body is dead-lettered at once — it never decodes on
redelivery, and must not wedge the queue.
Binding-conformance tests against a disposable broker (a stand-in for the
mesh-hosted broker, ADR 0001): headers on the wire with a pure body, the
redelivery-limit dead-letter, and the poison-body dead-letter.
Claude-Session: https://claude.ai/code/session_01LrgweAeERJYBg88c5cKDzF
The per-node process that makes a module's tools serve on the mesh:
- broker-amqp.ts: a concrete AMQP implementation of the sdk's Broker
contract (request/reply over a reply queue + correlation id, publish/
subscribe over a topic exchange). Kept here, not in the sdk, so a
broker-client change never rebuilds a module (ADR 0044).
- runtime.ts: bind the broker, import the assigned modules' tool
entrypoints (each registers as it loads), serveTools. The thin wrapper.
- main.ts: the entrypoint, configured by MESH_BROKER_URL + MESH_TOOL_MODULES.
- Dockerfile: the container a node runs it as.
Verified over a REAL broker: the test spins LavinMQ (the mesh's broker),
the runtime serves a registered tool, a separate connection invokes it by
name over AMQP and gets the result, and an unknown tool is refused over
the wire. So 'modules can serve' is now running-on-the-mesh, not just
proven in a mock.
Claude-Session: https://claude.ai/code/session_01LrgweAeERJYBg88c5cKDzF
jschoubben