A hive reads its own declaration today and that scopes cleanly: DIRECT.GET
carries the key in the subject, so the grant can name it. A *watch* cannot be
scoped that way — a consumer's filter travels in the request payload, so
$JS.API.CONSUMER.CREATE.<stream> grants the whole stream. With every hive in
one bucket, letting a hive watch its own declaration would let it read every
other hive's.
One bucket per hive (hive-wanted-<hive>) makes the stream a hive may hold
exactly as wide as what it is allowed to see, which is what #4006's live-watch
needs. That watch is a separate change; this only moves the boundary.
mara's calls, both on #4006: one stream per hive rather than teaching the auth
responder a hive roster, and a wildcard for the controller — "its okay if
swarm controller can theoretically override hive". A bucket name is a single
subject token with no prefix matching, so no wildcard narrower than * covers N
per-hive buckets; the controller's grant is account-wide by consequence, and
documented as chosen rather than left to look accidental.
The reader arm of #4005's key-layout guard asserted the opposite of that
ruling, so it is replaced rather than deleted: the hive arm survives as
no_hive_may_write_another_role_s_agent_status (with a positive control), and
the_readers_grant_is_deliberately_account_wide pins the decision and names the
ruling, so the width reads as chosen to whoever finds it next.
Two pre-existing negative assertions were silently defanged by the rename --
they matched hive-wanted.beta and $KV.hive-wanted.alpha, strings nothing
produces any more, and kept passing. Both now match current names.
swarm-controller resolves the store per hive per call instead of caching one in
a OnceCell: there is no single handle that serves N buckets, and declarations
change on operator action rather than per tick.
Making `AgentState` `Copy` in the preceding commit is a change to every
consumer of the type, not to the crate that declares it. `hive-c0re` grew its
own consumer while this branch was in review, and under `-D pedantic` a
one-byte enum taken by reference is `trivially_copy_pass_by_ref` and a
`.clone()` on it is `clone_on_copy`. Neither crate is wrong alone; the merge
is.
`decide` now takes the state by value and the call sites drop the `&`. No
behaviour change — the function only matches on the value.
mara's call on the PR: "dont make the enum open, we will just add
entries later". The catch-all variant is gone, and with it the per-agent
inert path.
What changes is where version skew lands, not whether it is handled. An
unrecognised value used to be one agent this hive left alone; it is now a
decode failure for the whole declaration, so a hive running older code
converges *nothing* rather than obeying the agents it happened to
understand. That fails closed instead of dangerous, and it is the right
trade when both ends ship together — which is what "add entries later"
assumes.
The test moved with the property rather than being rewritten in place:
`an_unknown_state_fails_the_whole_declaration` lives in
swarm-queue-client, where the decode is, with a valid entry beside it as
the control. `hive-c0re` keeps a coverage check that every state this
build knows produces an action somewhere — asserting inertness there
would be asserting something the type system no longer lets me build.
The deploy event is a nudge with no second path: core NATS is
at-most-once, so a hive that was down when the controller published
simply never learns that an agent is meant to exist here. This adds the
repair path — one boot-time DAG node that reads this hive's own key in
the `hive-wanted` bucket and converges the agents it names.
Two semantics settled on the issue thread, and both are places where a
plausible implementation is the wrong one:
- **Absence is not a deletion order.** No bucket, no key, or an agent
the value does not name all mean the controller has said nothing.
Swarm-side lifecycle does not yet cover agents that predate it, so
"converge to exactly this set" would tear down every agent the swarm
has not adopted. `plan` only ever inspects the agents a declaration
names.
- **An unrecognised state is inert.** `AgentState` is an open enum: a
value this build cannot read deserialises into `Unrecognised` and is
left alone. A closed enum would force "not `Up`" onto a state like
`paused`, so a controller that learned a new value would take agents
down on every hive not yet updated.
Divergence is measured against the hive's **stored power intent**, not
the container's observed running state — an agent that is down while its
intent says `Up` is already the boot reconcile's work, and a loop reading
`is_running` would insert a start DAG behind that reconcile's back on
every boot. A hive that already agrees with its declaration queues
nothing at all.
`queue_first_deploy` is extracted from the deploy-event path rather than
open-coded here, for the power-intent seed: without it `first_deploy`'s
tail `Reconcile` seeds `Wanted` from a container that exists but has not
started yet, which locks the agent to `Offline` on its first reconcile.
The read is authorised as-is: `store.get` takes async-nats' direct-get
arm (the KV bucket is created with `allow_direct`), which is exactly the
`$JS.API.DIRECT.GET.KV_hive-wanted.$KV.hive-wanted.<hive>` subject
`swarm-nats-auth` grants a hive. The fallback subject is not granted, and
a refused NATS request surfaces as a timeout rather than an error.
Nothing writes the bucket yet — the controller-side writer is the other
half of #3124, so this does not close it.
