| Filename | Latest commit message | Latest commit date |
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8459cc66bd
Two review findings from the previous round, re-checked against the actual tree rather than against my notes. `Scheduler::complete` was still a public wrapper whose entire body was `self.finish(id, outcome)`. Its docstring argued the split was not a redirect because both completion forms shared `finish` -- but sharing a private helper is not a reason for two public names. `finish`'s body now lives in `complete`, and `complete_growing` calls it. Same sharing, one name, no redirect. Growth on a failed node is now dropped by `complete_growing` instead of by the host loop. Failure cancel-cascades to every pending child of the completing node, and grown work is inserted as its children, so anything appended here is Skipped by the next statement -- the insert is not wrong, it is provably pointless. That is a consequence of this crate's cascade rule, so this crate should be the one enforcing it; a host that has to remember it can forget it. Behaviour is unchanged: hive-c0re already dropped growth before calling, and now no longer has to. `Scheduler::new_job` is left alone but documented for what it is: the hole in `JobBuilder::new`'s pub(crate) wall, with no non-test caller since claim_next mints a builder per running node. Closing it is a venue question rather than a rename, so it stays for now. |
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| .. | ||
| src | ||
| Cargo.toml | ||
| README.md | ||
hive-jobq
A persistent job-DAG scheduler, extracted from hive-c0re's in-tree job_queue
as a domain-agnostic library. It schedules a single persistent graph of
nodes over named resources; it knows nothing about containers, rebuilds, or any
hyperhive type — the node payload N and resource name R are both generic, so
the caller supplies its own domain.
When to use it
Reach for this crate whenever you need to run a DAG of interdependent work items under bounded, named concurrency — the hive-c0re rebuild/lifecycle queue is the first consumer, but nothing here is specific to it. The caller defines the node kinds, wires deps, and supplies a runner; the scheduler decides what can start.
Model
One persistent graph for the whole system, not a DAG per job. Enqueuing inserts a self-contained sub-DAG and returns the ids of the nodes the job asked for, in the order it named them; the scheduler runs a continuous loop, starting every node whose deps are satisfied:
- Resource deps are named counting semaphores over a caller-chosen type
R— e.g.build-slot(capacity N),agent/<name>(capacity 1), or any unconfigured name (capacity 1, created on use). A node acquires all its resource deps atomically at start (all-or-nothing) — no hold-and-wait, so no deadlock. - Node deps wait on another node per
DepWhen:AfterOkneeds success (a failed dep cancels the dependent),AfterAnyonly needs terminal.
A node carries two independent axes: its Deps (ordering + resource needs) and
its parent (structural grouping). The parent chain, not the node edges, is
what the scheduler consults for resource re-entrancy: a resource unit is held
for the acquiring node plus its whole parent subtree, and a descendant needing
a resource an ancestor already holds re-uses that grant (a re-entrant borrow,
one branch at a time) rather than taking a fresh unit.
A NodeId is opaque, stable, and monotonic (safe to persist). The scheduler is
single-threaded — it owns the resource table and mutates it directly.
Shape
Graph<N, R>— the persistent node store.insertmints ids and validates dep/parent references;set_stateis the single state-transition choke point (and where each node's lifecycle timestamps —started_at/finished_at,DateTime<Utc>— are stamped).Node<N, R>—{ id, parent, payload, deps, state, started_at, finished_at, error }. All fields public; derives serde for persistence + the wire.Scheduler<N, R>— drives the graph:settle()starts every ready node (acquiring resources atomically),complete(id, outcome)reports a finished node's result and rolls terminality up the parent chain, releasing grants once a subtree is done.Outcome::{Done, Failed(String)}— the failure reason ridesFailedonto the node'serror.ResourceTable<R>— per-name capacities; unconfigured names default to capacity 1.
See the crate-root and scheduler module //! docs for the full borrow/release
model.