# hive-jobq-metrics

OTEL export of a [`hive-jobq`](../hive-jobq) graph's state rollup, using the
same [`hive-jobq-wire`](../hive-jobq-wire) `state_rollup()` counts a viewer's
`/rollup` endpoint would serve — ridden out to the collector on a timer
instead of only on request.

**Why this is not part of `hive-jobq` or `hive-jobq-wire`.** Both of those
crates are dependency-light on purpose (no `tokio`, no HTTP client) — the
scheduler is logic, the wire crate is presentation, and neither wants to drag
the OTEL SDK, an async runtime, and an OTLP HTTP client into every consumer
that just wants to run a graph or serialize one to JSON. Metrics export is a
third concern with its own weight, so it gets its own crate rather than
bloating either of theirs.

`spawn_exporter` is generic over `hive_jobq::scheduler::Scheduler<N, R>` — any
host's jobq instance can call it, not just one hardcoded caller. It holds no
process-global state: call it once per graph you want exported, and keep the
returned `SdkMeterProvider` alive for as long as export should continue
(dropping it stops the `PeriodicReader`).