Struct Engine 

pub struct Engine {
    pub router: Arc<PartitionRouter>,
    /* private fields */
}

The FlowFabric engine: partition routing + background scanners.

Fields

router: Arc<PartitionRouter>

Implementations

impl Engine

pub fn start(config: EngineConfig, client: Client) -> Self

Start the engine with the given config and Valkey client.

Spawns background scanner tasks. Returns immediately.

pub fn start_with_metrics( config: EngineConfig, client: Client, metrics: Arc<Metrics>, ) -> Self

PR-94: start the engine with a shared observability registry.

Used by ff-server so scanner cycle metrics funnel into the same Prometheus registry exposed at /metrics. Under the observability feature (flipped via the same feature on ff-server / ff-engine), the handle records into an OTEL MeterProvider; otherwise the shim no-ops.

pub fn start_with_completions( config: EngineConfig, client: Client, metrics: Arc<Metrics>, completions: CompletionStream, ) -> Self

Start the engine with a shared observability registry and a completion stream for push-based DAG promotion (issue #90).

The stream is typically produced by ff_core::completion_backend::CompletionBackend::subscribe_completions. The engine spawns a dispatch loop that drains the stream and fires ff_resolve_dependency per completion, reducing DAG latency from interval × levels to ~RTT × levels. The dependency_reconciler scanner remains as a safety net for completions missed during subscriber reconnect windows.

pub async fn shutdown(self)

Signal all scanners to stop and wait for them to finish.

Waits up to 15 seconds for scanners to drain. If any scanner is blocked on a hung Valkey command, the timeout prevents shutdown from hanging indefinitely (Kubernetes SIGKILL safety).