| Filename | Latest commit message | Latest commit date |
|---|---|---|
9c97365f8f
Follows the jobq change: a builder can no longer be constructed or inserted outside `hive_jobq`, so `DagSpec` cannot hold one. It carries a `Declare` — `Box<dyn FnOnce(&Job) + Send>` — and the queue runs it against a builder jobq owns, at the moment it inserts. `NodeOutput.append_subgraph` becomes `Vec<Declare>` for the same reason, and this is where the shape was always heading: that field's doc already said an executor "cannot reach the queue, so it hands the declaration back", while its type was a `Vec<Job>` the executor had built itself. The rejected `build_nodes -> Vec<NodeSpec>` was the first version of that escape hatch; a recipe is the last one, because there is no job-shaped value to hand over at all. Templates and the power-op assemblers move their owned data into the closure and are otherwise unchanged — `rebuild_nodes`, `node` and the tail helpers already took `&Job` and returned handles, so only each template's outermost frame moved. Two `Debug` impls are hand-written: a closure has nothing to show, and its nodes do not exist until the queue runs it. `NodeOutput` reports how many subgraphs were emitted, `DagSpec` its source and reason. `append_subgraph`'s `is_empty()` early-return is gone — you cannot ask a recipe whether it will declare anything without running it. It now inserts and returns an empty id list if nothing was declared, which takes the queue lock in a case that previously skipped it. The two in-DAG-growth tests build `Declare`s now, so they exercise the shape an executor actually produces rather than one only a test could construct. 45 job-queue tests unchanged and passing. |
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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 new node ids; 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.