The mesh names a machine's bus user node.<name>; the host dialled with the bare
name and every machine was refused the first time it reached the server:
"authentication error - User". Same string as the composed user list, or nothing
connects.
The last of the host's link that still named a transport. `Asking` is one
enrolment conversation — a connection made with the token, a question asked, and
an answer waited for — and it is its own seam rather than part of `Link` because
almost nothing about it is the same: the credential is a one-time secret, there
is no declaration to hear, and a node that fails here is not in the mesh at all,
where a node that fails in `Link` has merely lost touch with one it belongs to.
`Enrol`'s thirteen arguments became an `Approach` — where, which certificate,
which bus — and the request it already had. The token says nothing about which
bus, and does not need to: every token names the one the mesh runs on today until
the rollout.
**The reply address is the whole of what changes on the new bus**, and it is
forced rather than preferred. Verified against a running server, both halves: the
answer reaches the node at the address its request carried in the payload, and
the transport's own reply field held something else entirely by the time the
consumer saw it — the consumer's ack address, exactly as design 25 §2 says. The
test asserts the field is *not* the node's inbox, so a future server that stopped
claiming it would fail this rather than let the reason quietly become folklore.
The inbox is under `_INBOX.enrol.<node>.`, which is exactly what the enrolling
user may subscribe and no wider, with a random tail per attempt: a reply left
over from an attempt that timed out is not the answer to this question, which is
what the correlation id does on the other transport. Subscribed before anything
is published, because a node that published first could miss an answer to a
question nobody was listening for.
The outbound half went behind `Bus` and a node's two statements stopped naming a
transport. This is the other half, and where the transport reached furthest: the
run loop selected on a channel of the client library's own delivery type, so
every part of holding a node in its mesh knew which bus it was on.
`Link` is dialling, hearing and saying in one interface, because dialling is
where the transport is chosen and choosing it twice is how one half of a node
ends up on a different bus from the other. `Declaration` has one way of being
done rather than two: a declaration set aside for a newer one is settled exactly
as an applied one is, on both buses, and the difference is a fact the report
carries.
Four things this settled.
**The host declares nothing on the new bus.** On the bus the mesh has it declares
its own queue, because a queue that is not there means a node that hears
nothing. Here it binds to a consumer the mesh made when the node enrolled, and a
missing one is said as the mesh's to answer rather than quietly created with
whatever this client happens to default to.
**The pin is easier here than in the tool runtime, not harder.** The Go client
takes a *tls.Config, so the same PinnedConfig with the same VerifyPeerCertificate
does the work — the subject-alternative-name constraint recorded against the
runtime's client is that client's, because it takes PEM strings with no verify
hook. A host checks the fingerprint and nothing else.
**Binding needs the subject as well as the consumer.** An empty subject is
refused rather than taken to mean "whatever that consumer delivers", which the
server said plainly and only when asked.
**Reconnection stays the caller's.** Hold already decides when to try again and
how long to wait; a client reconnecting underneath it would make that reasoning
a duplicate of the library's.
The drain keeps its live half and loses its catch-up half, as it said it would:
verified that three declarations pushed to an absent node leave one on the
stream, and it is the newest.
One test-harness lesson worth the comment it got: delete-then-add is not a reset.
A test that did that inherited the previous test's messages, and the symptom was
a declaration counted as delivered twice — which reads as a redelivery bug in the
code under test rather than as a dirty stream.
jschoubben