The provisioner's watches of gitea.bound, mesh-vault.bound and postgres.bound failed every minute for an hour on
the control-node ("the current values ... did not arrive in 10s") and 1257 changes were refused as "names no
watch of this bundle". Both sides were at fault. The SDK answered a change only once its handler returned, so a
slow handler (Rejudge waits on the lock its composition holds) counted against the runtime's 10 s bound on the
current values; and when the runtime gave up, the SDK forgot the id at once. The runtime (mesh-tools node-tools
internal/bus/state.go StateWatch) stops its watcher on that bound but still drains and delivers the values already
buffered, to an id nobody holds.
Quick fix: a longer runtime bound. Thorough fix here: each state and provision watch has a follower that takes a
change in order and answers at once, its handler on its own goroutine; Watch still returns only once the current
values were handled, and a handler's error is said on standard error. A watch the runtime refuses is said given up
and kept by id, so a change still handed to it is refused saying so. KeptState.Follow asks again with backoff until
taken, the loop four modules wrote for themselves. A log watch keeps its answer after the handler: that is its
back-pressure.
mesh-grants' sealed grants and the controller's merge record each met "message size exceeds maximum" (JetStream
10054) only after the put, and a writer that retries looped on a value that can never land; an update over the
limit was even answered as a revision mismatch, which every compare-and-set writer retries.
Quick fix: cap the two values in their modules. Thorough fix, chosen because the kind was met twice and every
module writes through the SDK: the package kvlimit checks a value against its bucket's largest message (read from
its stream and kept) before the put, naming the bucket, the key, the size and the limit, and turns the bus's own
refusal into the same *TooLarge (errors.Is kvlimit.ErrTooLarge), so no writer retries it. The SDK's own writers
use it: process.State (Put, Create, CreateTTL, Update), process.AwaitedBucket, the runtime state of a bundle
(stdio KeptState, against the module state's 256 KiB) and mesh-hand-compose. A value that can outgrow its bucket
is split over keys or kept in the object store with its name in the key.
state(name) / stdio.State(name): get, put, delete, keys and watch over the
runtime's mesh/state verbs. A watch's handler is registered under the id it
is asked with, so its current values — which arrive before the watch is
answered — and its changes reach it and no other watch.
jschoubben
jochen