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Cloacina

Reactor

A Reactor is the long-lived process that binds a set of named Accumulators to a Computation Graph, maintains an input cache from the Boundary events they emit, and fires the graph when its criteria are satisfied. The firing criterion is a top-level primitive: a graph subscribes to a reactor by name.

Mental model

Section titled “Mental model”
  • A reactor declares which accumulators feed it and a criterion: when_any (fire when any source has new data) or when_all (wait for all).
  • It keeps an input cache and an input strategy — latest (overwrite with newest) or sequential.
  • When the criterion is met, it calls the compiled graph with the current cache.

Interfaces

Section titled “Interfaces”

#[reactor] declares the reactor as a top-level primitive on a struct:

#[cloacina_macros::reactor(
    name = "pricing_reactor",
    accumulators = [orderbook],
    criteria = when_any(orderbook),
)]
pub struct PricingReactor;

(The lower-level runtime exposes Reactor::new(graph_fn, ReactionCriteria::WhenAny, InputStrategy::Latest, …) — see the embedded tutorials.)

Key facts

Section titled “Key facts”
  • A reactor is a specialized trigger (CLOACI-S-0011): where a workflow trigger polls or follows a cron schedule, a reactor consumes accumulator boundary events and fires a computation graph.
  • Criteria: when_any / when_all over the named accumulator sources.
  • Input strategy: latest or sequential (Rust InputStrategy). There is no input_strategy clause on the #[reactor] macro — set it programmatically or in the package manifest; see Sequential input strategy.
  • Naming: the accumulators names must match the accumulator source names and the graph’s entry-node source names.
  • Operator controls: manual fire is REST (POST /v1/health/reactors/{name}/fire, cloacinactl reactor fire|force-fire); pause/resume is WebSocket-only (/v1/ws/reactor/{name}) — there is no REST pause route, and reactor→workflow subscriptions have no HTTP API at all (runner API only).

See also

Section titled “See also”