Design 25 §7. A person is not a module and holds no seat: nothing is
addressed to them, nothing is delivered to them, and they have no durable
consumer. What they have is permission to ask, as a list of tools or `*`
for an administrator.
Four properties the tests hold it to, each of which is a way of being
wrong that would not announce itself: a person reaches nothing but tools,
so one cannot claim a module said something; no ack subject, because
authority over a consumer that does not exist is authority nobody would
audit; no allow_responses, because a person who can answer a request is
impersonating a module on a bus where anyone may serve a tool; and two
people do not share an inbox.
Design 25 §2 builds enrolment around carrying the reply subject in the
payload, because a JetStream consumer claims the transport Reply field for
its own ack address. The whole handshake rests on it, so it is checked:
the caller asked for _INBOX.LCr3M83q... and the consumer saw
$JS.ACK.PROBE.probe_consumer... The design was right, and the workaround
is necessary rather than defensive.
Worth having as a test rather than a note: if a future server version
stopped doing this, enrolment would keep working and the reason for the
payload field would quietly become folklore.
Step 3.4. On the new bus there is no reply queue to declare and no
correlation to check: each account is granted one inbox prefix and no
other, so an answer cannot reach the wrong asker. That settles a cost
build.go records having paid — on a shared reply exchange every asker saw
every result, which is why the correlation was checked rather than assumed.
And a tool nobody serves says so at once rather than after the whole wait.
The difference between "that module is down" and "that tool is slow" is the
first thing a person asking wants, and both tests are against a real server
because both are claims about what the server does, not about this code.
RequestBuild stays as it is, and is a different shape on the new bus rather
than the same one: a build takes minutes, so it is work submitted to a
queue with the outcome returning to a reply subject the request carries —
the pattern design 25 §2 already sets for anything crossing a stream. It
touches the builder too, so it goes with that conversion.
introduces
Step 3.4, the consume side's hard part. The guarantee (ADR 0083) is that a
push the controller cannot record because its store is restarting is held
and retried — never dropped, never falsely acknowledged. Keeping the
delivery unacknowledged in memory becomes a nak with a delay: the server
holds it, the controller keeps no list of parked messages, and a controller
that restarts mid-window loses nothing it was holding.
That is a plain win and it introduces one problem. Holding in memory let
the controller drop an older report when a newer one for the same node
arrived, "because acting on it after the newer would undo the newer". A
naked message is the server's and comes back whatever happened meanwhile,
so the older report is redelivered after the newer was applied.
The answer was already in the message. A report carries `Declared`, the
digest of the declaration it is about, which exists because an earlier
attempt to order reports by time lost the race it invited. So supersession
stops being something the controller remembers and becomes something it
checks — the same shape as a node refusing a superseded declaration by
sequence (issue 107): ordering settled by what a message says, not by when
it arrived.
Pure, so the guarantee is testable without a bus, a store or a clock. Nine
tests, including that staleness is decided before the store is waited on —
a redelivery that lost its race must not hold a slot a current message
needs.
A declaration-level test composes the shipped networking module with a
resolver and asserts /etc/hosts arrives as mesh-wireguard.fact-node-names
with into: block and region-only content, that the resolver's restart-on
still names it, and that a resource's at passes through untouched — a
composition step dropping into would otherwise go unnoticed. plan --show
marks files written into, so a region is not read as the whole file.
The rollout order is spelled out: every node's host, the controller's
own included, must be block-aware before this controller ships (hq 128).
Comments framed the new bus by what it replaces — a comparison in almost
every explanation, which reads as though NATS were a variant of the old
thing rather than the mesh's nervous system. Removed throughout, and
OverAMQP becomes OverCurrent: the seam's two sides are the bus the mesh
runs on today and the one being built, not two protocols.
What remains is the client library's own package name, which is its name.
Step 3.4, first half. Every one of these took an *amqp.Channel, so the
transport reached every caller and swapping it meant touching all of them.
The seam turned out to be small — the controller sends exactly two kinds of
message that expect no answer — which is the same measurement that said
this bus could be replaced at all.
Bus is stated in the mesh's words, not a transport's: PublishEvent and
PublishDeclaration. Two implementations, both shipping, because steps 1 to
4 leave every node on AMQP and the NATS one is selected at the rollout.
Both ship is also what makes them comparable: one conformance fixture holds
both to the same envelope, and the NATS one is checked against a real
server reading back from the stream rather than from the code that wrote it.
Still on *amqp.Channel: RequestBuild and Ask, which carry reply-queue
machinery, and the whole consume side — the control loop, enrolment, serve.
/etc/hosts is the machine's: the distribution's localhost lines, the
operator's own entries, and marked blocks other tools maintain there.
Writing node-names whole replaced all of it the moment the private
network was taken, and every later write by those tools was lost at
the next machine joining. The node-names fact is now emitted with
into: "block", so the host owns only its marked region and keeps the
rest byte for byte. The region holds only the mesh's names: no header
claiming the file, no localhost, no 127.0.1.1 line — the floor was
never the mesh's to write. How a fact is written is a property of the
fact in the closed table; node-zones stays a whole file the mesh owns.
Sequencing: a host older than the block mode refuses the whole
declaration on an unknown into, so every host must be upgraded before
this controller is rolled out.
the-uplink joins the closed set as a node seat delivering nothing. Its
holder is the module for the machine's own network manager, and keeps
that manager from contradicting the mesh — the resolver file left to
resolv-conf, mesh0 left alone — without ever declaring a link. Held
per machine, so a machine running two managers is refused at
assignment rather than found by its resolver being rewritten. The
count test moves to fifteen; one test holds the seat's shape.
Every required header set, each value in the pinned shape, and the subject
derived the same way. Read from the sdk's conformance directory by sibling
path, never copied.
The host refuses an empty body unless told the emptiness is meant
(mesh-host#29). When a node's declaration composes to no resources —
which #77 now sends rather than skips — Body() sets owns_nothing, so
the node applies it and drops what it last held. A declaration with
resources never carries the marker. One test.
Design 29 §1's load-bearing rule: a module names its events, tools and
seats locally and the mesh derives the subject, so reorganising the subject
space leaves every manifest correct. It held by construction, and a rule
held by construction is one a later field breaks quietly.
push skipped any node whose declaration composed to zero resources. A
node that HELD something before — the broker opening a placement gave
an adopted node, say — then kept it forever: the empty declaration that
would drop it was never sent, and the node's own heartbeat re-applied
the stale resource with no way for the mesh to say it is gone. Now the
empty declaration is sent; the host drops what the mesh owned and keeps
what it found. A node that never held anything applies it as a no-op.
Surfaced on ace: the foundation-opening fix (#74) removed its only
resource, and the correction could not reach it until this.
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.
Carries MTU from the reported tunnel (mesh-host#28) through inventory,
the overlay graph's TakeOver, into the generated config's [Interface].
A tuned path keeps its MTU across the takeover instead of regressing to
1420 and hanging transfers no ping would reveal. Two emit tests; a
tunnel with no MTU writes no line.
A home node behind NAT (no Endpoint → not Reachable) that took over a
tunnel must still listen on that tunnel's port: its LAN peers dial it
there. ListenPort was gated on Reachable, which conflated 'a peer dials
me here' with 'the hub can dial me' — so the takeover guard refused
overlay-up, and the guard's suggested remedy (re-place with an
endpoint) breaks a NAT'd node's path: it stops keepalive and hands the
hub a private LAN address to dial. TakeOver now carries the found
tunnel's port (already known to the controller), and the interface
listens on it when the node is not otherwise reachable. Two tests;
Endpoint-reachable nodes keep the old path unchanged.
Task 3.9's other half and 1.4's missing client. The derivation is pure and
unit-tested; only "does the server accept this" needs one running, behind
MESH_TEST_NATS so the ordinary suite stays offline.
A seat's work queue is created at registration, not assignment, so work
queues until a holder appears — a stream created at assignment would make
"the holder is not here yet" mean "your messages are gone". Named after the
seat, because the holder can change and the queued work must not care.
A holder's worker uses a queue group even though the seat guarantees one
holder: the seat is authority, the queue group is delivery, and tying them
together means the day somebody allows two holders every message is
processed twice with nothing reporting it.
One consumer per module carrying every filter, because its ack permission is
derived from its name.
And a real bug the live server caught: a durable name may not contain a dot,
but an ack subject is $JS.ACK.<stream>.<consumer>, so the single string that
read correctly inside the permission was rejected as a consumer name. Split
in two, beside the permission that has to match. Unfixed, the symptom would
have been every message redelivered forever with a permission list that
looks right — which is the failure design 25 §4 warns about.
Enrolling ace applied adoption.opening-tcp-5671-incoming to it, opening
5671 from anywhere (v4+v6) where nothing listens — the ace session
caught it. foundation ports widen the broker's from:mesh port to
from-anywhere so a machine that is not yet on the mesh can make its
first dial; that belongs on the broker's host alone. foundationPortsFor
keeps the port only when a module resolved onto this node listens on
it, so novox opens 5671 and a node that merely dials out opens nothing.
Two tests, both directions.
The manifest carries seats and uses; registration refuses a mesh-* name, a
duplicate declarer, an undeclared uses or claim, a seat with no protocol, a
scope mismatch, and a holder that does not answer what its seat promises.
The parser stops judging unknown claim names, because it cannot: another
module may declare that seat, and one manifest cannot tell. The test that
encoded the old rule is rewritten to assert the refusal at registration, and
a new one pins the case the parser could not have distinguished.
Tools are declared for the first time, under their own key — serves already
means a provision's facts.
NATS refuses overlapping streams rather than double-storing, which is the
opposite of what the Overlaps comment claimed. The check still earns its
place — it names both streams at composition rather than one at apply — and
the refusal is what rules out a shared stream beside per-module ones.
Step 2.3 of novox/hq ADR 0116. The refusal is the resolver's existing one;
these pin it for this seat, including that a different bus implementation is
refused for the same reason — the property that lets the bus be replaced.
Task 1.4. The foundation set only — a seat's streams come at registration
and a module's consumers at assignment, neither of which has happened at
genesis (ADR 0118).
Asserted rather than created: a stream that was deleted, or a mesh raised
from a backup, must converge rather than run without the guarantee its
messages assume.
Two things the definitions have to get right, both tested:
- CONTROL names its subjects instead of taking mesh.control.>, because
heartbeats live under that prefix and a stream of them competes for
retention with the messages that matter
- EVENTS filters on the event token, which is why that token exists; a
filter over a module's whole namespace would persist every tool call
Overlapping filters are refused where the set is written: NATS accepts two
streams matching one subject and stores the message twice under two
retentions, which nothing reports.
Adds nats.go as a dependency; it pulled golang.org/x/* forward. Full suite
green.
Task 1.3 of novox/hq ADR 0116. On AMQP an account was an HTTP call; on NATS
it is text the controller composes and the server reloads (ADR 0106). Pure,
so the mesh's whole authority model is testable as strings.
NATS closes a gap management.go recorded rather than hid: LavinMQ has no
topic permissions, so an emitter was granted the events exchange whole and
ADR 0042's origin reservation was "stamped by the sdk, not enforced here".
Per-subject permissions make it the server's refusal.
Two things found by composing a real file rather than reading the design:
- a scoped inbox leaves a responder unable to reply, because the answer goes
to the caller's inbox. allow_responses is the answer — one reply to the
subject of a message actually received — and only principals that serve
are granted it. Recorded in design 25 §4.
- composition must be deterministic: the module's entrypoint reloads on the
file's digest, so an order-dependent composer would reload the whole bus
on every controller restart. Covered by a test.
The golden fixture is the exact text `nats-server -t` accepts, so the syntax
is the server's rather than one we invented.
The tunnel the hub took over routes to machines the predecessor knows
by name and the mesh knew only by address — taking the resolver in that
state silences three machines at once. Now the operator states which
machine a carried address is (overlay name <address> <name>), the
statement rides tunnel_peer.named, and namesInTheMesh answers for named
not-yet-enrolled peers — one reading, so the hosts fact, a container's
hosts and the resolver cannot disagree. Enrolment verifies the word:
a machine enrolling under a named peer's key with a different name is
refused where the operator can read it, the stated name keeps the
carried address, and an enrolled peer's name is the node's — naming it
again refuses. The issue's rule holds: a name the predecessor answers
for keeps resolving until the machine behind it is a node.
The bus is the only broker (novox/hq ADR 0117): messaging is subjects on it,
scoped by a module's own emits/consumes, not a server handed out as a
provision. So the seat joins mesh-controller and the-catalogue in delivering
no interface. Full suite green.
One assignment of a module per node is now the rule, not a limitation —
the operator dropped the multi-assignment requirement, and the schema's
(node, module) key has been the decision since migration 0005. What
changed: Assign reports whether the assignment was new, and the command
says 'already runs — one node runs one of each (ADR 0115); nothing
changed' instead of printing 'is assigned' for a no-op, which read as
an action that happened. Idempotence stays: a repeat is exit 0, because
a script stating what is already true is not wrong.
checkResources compared paths as written, so ${dir:state}/server.env —
the same characters in every module, a different directory in each —
refused the first two placed modules that met. Paths are placed before
they are compared, under the default root, which keeps every real
collision: distinct modules' places are distinct under any one root,
and a module stating another's placed root is caught because a pathless
directory now owns its placed path in the comparison too.
Slice two of ADR 0112. A pathless directory saying place "." is the
assignment's one directory, <root>/<module> — to-be 27's shape — and
place never reaches the host, which parses strictly. The maps naming
where bindings, credentials and contributions land (binds, secrets,
own-secrets, receives, grants) fill against the placed directories at
composition, into fresh maps and a fresh module slice, because one
resolution composes for many nodes. The five absolute-path checks on
those maps accept a placed reference — resolution makes it absolute
before anything reads it — while certificate, operator-keeps and
accesses paths stay absolute-only: those are the operator's or another
vocabulary's. unknownDirRefs scans the maps too, and validates place
itself: only on a directory, only ".", never beside a stated path.
Found by the foundation tests validating the sibling catalogue: the
first conversion's blanket replace turned /var/lib/gitea/database.json
into ${dir:data}base.json — which resolves to the right path by pure
string concatenation. Production was saved by a coincidence; the
catalogue cleanup that follows spells it ${dir:state}/database.json.
The first executable slice of ADR 0112 / to-be 27, sized to what the
operator settled tonight: a module definition names no host path for
its own data. A directory resource may omit path; composition resolves
it to <root>/<module>/<id>, the root a node's setting on Rendering with
/var/lib as the default — which reproduces exactly the layout novox
converged to by hand. ${dir:<id>} names the place from a resource's
path, content, mounts, environment and env-files, the same shape as
${bound:…}. A directory that states a path keeps it and still answers
by name — that is the adopted-data placement, mssql its live case.
Resolved in the controller at composition, so the wire format and the
host change not at all; a reference naming no directory refuses at the
manifest and again at composition; nested fills are rebuilt, never
written into the manifest's own maps, because one manifest composes
for many nodes.
Proxy configuration beside insecure, not a fifth policy — ADR 0108 closed that set at four, and both
of these tune how a request is carried rather than deciding what a name admits. A registry is the
case that needs it: image layers arrive as single requests of gigabytes and a proxy's own default
refuses them long before the workload is reached.
Absent is no limit, which is what every route already got. A limit that is not a whole positive
number of bytes takes the route with it, named in the log like a port that is not one — serving it
without the limit would carry exactly what the module said not to carry. Enforced on the declared
length where there is one, and while reading for a chunked body, which declares none: without the
second, a limit is advice.
The swap from a named volume to the host directory left the mount undeclared, which main's own
manifest check now refuses: a bind the module did not declare is created by the runtime as root, so
the module's owner and mode never reach it and ADR 0030's data rule does not cover it.
The directory is the broker's — lavinmq declares it as its own, mode 0700 — so from here it is an
access, read-only: a pre-existing path this module is granted use of and does not own.
jschoubben
jochen