StationServices class

The STATION-level ambient services a node resolves from the tree in one inherited lookup (ADR-0009 D2/D3 — the MediaQuery pattern: related ambient data, one lookup, scoped to the station).

The kernel provides exactly one of these via an InheritedSeed<StationServices> at the tree root, so every mounted node reaches the machine's process transport (provider), the single bd write chokepoint (writer), the owned state substation (stateSubstation), and the optional adopt-liveness seam (liveness) — all genuinely per-machine. Nothing substation-scoped lives here (ADR-0008 D5): the workspace/branch layout + source control are the per-SubstationScope SourceControl's (ServiceBundle), not the station's — so a non-git / non-source effect is expressible and the engine holds no worktree-layout opinion (ADR-0007 §1).

Immutable and value-light: a handle to long-lived collaborators, not state. A node captures it once in didChangeDependencies and uses the captured reference across async gaps so it never touches the TreeContext (which throws post-unmount) for I/O.

Constructors

StationServices({required RuntimeProvider provider, required StationBeadWriter writer, required String stateSubstation, AllocationLiveness? liveness, WorkSignalProbe? workSignal, int maxConcurrentWork = kDefaultMaxConcurrentWork})

Bundles the station's process transport provider, the bd write writer, the owned stateSubstation, the optional adopt-liveness seam liveness, and the concurrency-governor station default/ceiling maxConcurrentWork.

const

Properties

hashCode → int

The hash code for this object.

no setter, inherited

liveness → AllocationLiveness?

The engine pgid-liveness half of the daemon adopt-freshness proof (ADR-0009 D4) — the Host threads it into each AllocationContext.liveness. Null (the default) ⇒ neverLive ⇒ the Host never adopts at mount (P1 offline). All-or-nothing with the RestartReconciler's adoptProof: the composer wires BOTH (from a real ProcessGroupController) at the live arm, or leaves both off — wiring one alone double-runs. This makes the two adopt halves symmetrically wireable (closing the adversarial-review footgun).

final

maxConcurrentWork → int

The concurrency governor's STATION-WIDE default/ceiling (tg-42f, declare-and-check — ADR-0008 D8 defers the general per-leaf DartEnvironment permit governor; this is the narrower, cheaper work-bead slot budget the mount boundary checks). Serves two roles: the DEFAULT a substation's own SubstationConfig.maxConcurrentWork falls back to when unset, AND the hard TOTAL ceiling across every substation WorkList mounts under this station — a substation override only narrows within that ceiling, never raises it. Threaded from --max-agents (StationArgs.maxAgents); defaults to kDefaultMaxConcurrentWork so a single-bead flow is unchanged.

final

provider → RuntimeProvider

The process transport — spawn (start), kill (stop), and the broadcast lifecycle RuntimeProvider.events stream the effect subscribes to.

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

stateSubstation → String

The_grid's OWNED state substation (tgdog) — the partition session beads are minted into, kept separate from the read-only work source (A37).

final

workSignal → WorkSignalProbe?

The station's work-signal probe — the COMPLETION FENCE's binding. The Host threads it into each AllocationContext.workSignal. Null (the default) ⇒ noWorkSignal ⇒ the fence is INERT and an inferred one-shot exit is taken at face value (today's behavior). The live composer binds it to its own source-control service's uncommitted-work probe, EXCLUDING the grid's own runtime dir (grid_sdk's stationWorkSignal) — that impl is the composer's opinion, never the engine's (ADR-0008 D5). Unlike the adopt seam, this one is safe to arm ALONE: it can only WITHHOLD an unproven completion, never double-run anything.

final

writer → StationBeadWriter

The single bd write chokepoint — the ONLY path session/lifecycle beads are written through (createSession / update / close), bd-only, --actor grid-controller, fail-closed on ownership (ADR-0006 Decision 2).

final

Methods

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited