novox/hq ADR 0118: the prefix is the reservation rule, so a module
declaring any mesh-* name is refused and there is no reserved-names list to
drift. Ten seats renamed in the table, the manifests that claim them, the
controller's own shipped manifests, and the tests.
Not the migration 0118 expected: a holding is derived at resolution from
manifests and never stored, so nothing recorded points at an old name. A
kept rename table tells a manifest written against one what it became —
kept rather than retired, because a module lives in its own repository and
may be registered long after the catalogue stopped using it.
**A seat is not the interface it delivers.** The git seat became mesh-git
and the git provision did not; likewise the package registry. A blanket
replace renamed both, and the failure read "the package registry is served
on <nil>", which does not say "you renamed an interface". A test now pins
every seat against what it delivers, and that neither name is also the
other.
Two different things were both written `requires`. A shell, a display
server and a private network have to be on the machine that needs them.
A database does not — it runs somewhere and is reached over the network.
Both were answered the same way, so requiring a database installed
PostgreSQL on every machine that ran a web application.
What a module provides now carries a scope, the same idea claims already
use, written short in the ordinary case:
"provides": ["shell"]
"provides": [{"name": "database", "scope": "mesh"}]
A mesh-scoped requirement is answered by finding the node already running
it — never by installing it here. Choosing a machine to put a database on
is a decision with consequences, and nothing resolving a web application
should make it silently. With nothing anywhere it refuses and says which
module to assign; with two it refuses and says how to choose.
Choosing is `pin <node> <provision> <from>`, kept per node because that
is the granularity the choice has. A pin at a machine that does not
provide it refuses rather than falling back — a fallback would quietly
move somebody's data. One provider does not overrule a pin either.
Resolving a node now needs to know what the others offer, and working
that out needs them resolved, so it is two passes: the first answers only
what each node offers, the second answers everything. Nothing is ever
declared from the first.
A node's plan says what it takes from elsewhere. It is the only part of a
set that stops working when a different machine goes away, and nothing
else in that output would have said so. It is also where a credential
will hang once there is a mechanism for handing one back.
One test found passing for the wrong reason: it read pins through a join
on the provider, which hides a dangling row whether or not it was cleaned
up. It counts rows now, and bites when the cascade is removed.
Connectivity was code beside the module system doing the module system's
job: every machine with an address was on the private network and there
was no way to keep one off.
A manifest can now say its resources are computed by the control plane,
which is what a peer list needs — it is derived from every machine at
once, so nothing could be written in advance. The network is a module
from there on: assigned, resolved, settled, and absent from a machine
nobody gave it to.
Three modules rather than one, because WireGuard is one VPN of several:
mesh-wireguard provides private-network, mesh-addressing
claims the-private-network, one per node
mesh-names provides name-resolution, requires mesh-addressing
networking requires both, and ships no files of its own
The last is the point. Most people want the network up and do not want
to choose a VPN, so `assign networking` takes the only answer to each
requirement silently. The day the catalogue holds a second one there are
two answers, the resolver refuses and names them, and choosing is
assigning the one you want. No flavor field, nothing to configure.
Names left the WireGuard declaration for their own module. They would be
identical over a different private network, and bundling them made one
module out of two things.
Three faults the walk found:
- choosing tailscale still installed WireGuard, dragged back in by the
names needing the mesh's own addresses. Caught now by a claim: running
two VPNs is fine, being *the* mesh network is singular.
- a requirement wanted by two modules was reported twice, identically.
- "this mesh has no hub" was reported when the real cause was that a
node could not be resolved at all. It now names the node and the why.
And a test that asserts the manifests actually shipped, after the claim
went missing from the real one while every test stayed green.
jschoubben