50 lines
2.4 KiB
Rust
50 lines
2.4 KiB
Rust
//! The concrete resource type the rebuild queue schedules over — the bridge
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//! from hive-c0re's [`super::model::NodeKind`] onto the domain-agnostic `hive-jobq` crate.
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//! `hive-jobq` is generic over a resource type `R: Clone + Eq + Hash` and a node
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//! payload `N`; here `R` is [`Resource`] and `N` is [`super::model::NodeKind`] directly (each
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//! variant carries the agent it targets).
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//!
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//! **A node's resources are declared where the node is constructed** with
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//! `.needs(…)`, not derived from its kind. Deriving them made the requirement a
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//! property of the *kind*, which let a kind that happened to run under a
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//! holding ancestor declare nothing at all.
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//!
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//! All of a node's resource edges are acquired **atomically**
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//! (`try_acquire_all`) — a node never holds one resource while waiting on
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//! another, so the multi-resource nodes (a `MetaLock` wants a build slot *and*
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//! the meta window) cannot deadlock against each other.
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/// The two resource classes the queue gates concurrency on, as the crate's
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/// generic resource type `R`. What each holds, who declares it, and the
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/// exemptions: see `docs/scheduler/coordinator.md`'s _Scheduler semantics_
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/// (build slots, the per-agent lease) and _Two further layers protect the
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/// meta repo_ (the deploy window) sections — this enum stays the one-line
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/// summary, not a second copy.
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#[derive(Debug, Clone, PartialEq, Eq, Hash)]
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pub enum Resource {
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/// One of the `buildSlots` permits, held by a nix-heavy node for its
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/// duration.
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BuildSlot,
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/// The per-agent lifecycle lease — globally exclusive per agent across
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/// all DAGs.
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Agent(String),
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/// The meta-repo mutation window — a global singleton held by any node
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/// that mutates the meta repo, so two meta mutations never interleave.
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MetaWindow,
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}
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/// This resource's name on the generic graph wire.
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///
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/// `hive_jobq` is generic over the resource type, so a viewer that can render
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/// any graph gets a string here rather than this enum. The `agent:` prefix
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/// keeps the per-agent leases from colliding with a hypothetical global
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/// resource that happens to share an agent's name.
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impl hive_jobq_wire::WireResource for Resource {
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fn name(&self) -> String {
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match self {
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Resource::BuildSlot => "build-slot".to_owned(),
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Resource::Agent(agent) => format!("agent:{agent}"),
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Resource::MetaWindow => "meta-window".to_owned(),
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}
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}
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}
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