Struct EngineConfig 

pub struct EngineConfig {

    pub partition_config: PartitionConfig,
    pub lanes: Vec<LaneId>,
    pub lease_expiry_interval: Duration,
    pub delayed_promoter_interval: Duration,
    pub index_reconciler_interval: Duration,
    pub attempt_timeout_interval: Duration,
    pub suspension_timeout_interval: Duration,
    pub pending_wp_expiry_interval: Duration,
    pub retention_trimmer_interval: Duration,
    pub budget_reset_interval: Duration,
    pub budget_reconciler_interval: Duration,
    pub quota_reconciler_interval: Duration,
    pub unblock_interval: Duration,
    pub dependency_reconciler_interval: Duration,
    pub flow_projector_interval: Duration,
    pub execution_deadline_interval: Duration,
    pub cancel_reconciler_interval: Duration,
    pub scanner_filter: ScannerFilter,
}

Engine configuration.

Fields

partition_config: PartitionConfig

lanes: Vec<LaneId>

Lanes to scan for delayed/index operations. Phase 1: ["default"].

lease_expiry_interval: Duration

Lease expiry scan interval. Default: 1.5s.

delayed_promoter_interval: Duration

Delayed promoter scan interval. Default: 750ms.

index_reconciler_interval: Duration

Index reconciler scan interval. Default: 45s.

attempt_timeout_interval: Duration

Attempt timeout scan interval. Default: 2s.

suspension_timeout_interval: Duration

Suspension timeout scan interval. Default: 2s.

pending_wp_expiry_interval: Duration

Pending waitpoint expiry scan interval. Default: 5s.

retention_trimmer_interval: Duration

Retention trimmer scan interval. Default: 60s.

budget_reset_interval: Duration

Budget reset scan interval. Default: 15s.

budget_reconciler_interval: Duration

Budget reconciler scan interval. Default: 30s.

quota_reconciler_interval: Duration

Quota reconciler scan interval. Default: 30s.

unblock_interval: Duration

Unblock scanner interval. Default: 5s.

dependency_reconciler_interval: Duration

Dependency reconciler interval. Default: 15s.

Post-Batch-C this scanner is a safety net, not the primary promotion path. When a CompletionStream is handed to start_with_completions, push-based dispatch drives DAG promotion synchronously with each completion — under normal operation DAG latency is ~RTT × levels, not interval × levels.

The reconciler still runs as a catch-all for:

• messages missed during subscriber restart or reconnect;
• pre-Batch-C executions without core.flow_id stamped;
• operator-driven edge mutation that doesn’t pass through the terminal-transition publish path.

15s idle-scan cost is minimal. If the push dispatch loop is disabled (engine started via start/start_with_metrics without a stream), drop this to 1s to preserve pre-Batch-C DAG latency behavior.

flow_projector_interval: Duration

Flow summary projector interval. Default: 15s.

Separate observability projection path — maintains the flow summary view, NOT on the DAG-completion latency path. Kept at 15s in this config; a change to that cadence is unrelated to dependency resolution.

execution_deadline_interval: Duration

Execution deadline scanner interval. Default: 5s.

cancel_reconciler_interval: Duration

Cancel reconciler scanner interval. Default: 15s.

Drains ff_cancel_flow’s per-partition cancel_backlog ZSET of flows owing async member cancels. Each cancelled flow gets a grace window (30s by default, set by ff-server) before the reconciler picks it up, so the live in-process dispatch isn’t fought on the happy path.

scanner_filter: ScannerFilter

Per-consumer scanner filter (issue #122).

Applied by every execution-shaped scanner (lease_expiry, attempt_timeout, execution_deadline, suspension_timeout, pending_wp_expiry, delayed_promoter, dependency_reconciler, cancel_reconciler, unblock, index_reconciler, retention_trimmer) to restrict the candidate set to executions owned by this consumer. The four non-execution scanners (budget_reconciler, budget_reset, quota_reconciler, flow_projector) accept the filter for API uniformity but do not apply it — their domains are not per-execution.

Default: ScannerFilter::default — no filtering, pre-#122 behaviour. Multi-tenant deployments that share a single Valkey keyspace across two FlowFabric instances set this (paired with CompletionBackend::subscribe_completions_filtered) for mutual isolation.

Trait Implementations

impl Default for EngineConfig

fn default() -> Self

Returns the “default value” for a type.