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Endpoint-Created PollingConsumer for pollEnrich

Status: Accepted (2026-06-07)

Implemented in branch rc-3y0-eip-7 per plan docs/superpowers/plans/2026-06-07-rc-3y0-eip-7-content-enricher.md. All acceptance criteria from bd rc-3y0 met; quality gates green.

The pollEnrich DSL verb resolves its URI to an Endpoint, calls the existing Endpoint::polling_consumer() -> Option<Box<dyn PollingConsumer>> opt-in method, and invokes receive(timeout) on the result. We rejected the producer-side alternatives (file:...?mode=read bridge, new resource: component) because they invert the Tower Service<Exchange> producer invariant (write/send only) and would constitute fake URI reuse across the data plane, violating ADR-0001 and ADR-0014. The PollingConsumer trait already lives in crates/components/camel-component-api/src/endpoint.rs; this ADR records the decision to wire it up for the EIP-7 Content Enricher use case rather than introduce a new mechanism.

Considered Options

  • A. Endpoint-created PollingConsumer (chosen) — reuse the existing PollingConsumer trait; endpoints opt in by overriding polling_consumer(). File/SEDA/JMS can return Some(...); HTTP server, Kafka return None.
  • B. Producer file:...?mode=read bridge — REJECTED: violates ADR-0014 (fake URI reuse) and inverts the producer semantic.
  • C. New ReadEndpoint trait — REJECTED: component-specific, doesn't reuse the existing consumer logic (filters, idempotency, path traversal).
  • D. resource: standalone component — REJECTED: same flaws as B plus duplicates filesystem logic.
  • E. Consumer downcast — REJECTED: ugly, doesn't generalize, requires every pollable component to share a concrete Consumer shape.

Consequences

  • Adding timeout: Duration to PollingConsumer::receive is a breaking change for any external implementor of the trait. Acceptable while the trait has zero implementors in-tree (all current Endpoint::polling_consumer overrides return None). Bump camel-component-api minor version.
  • FileEndpoint::polling_consumer() is the first non-None implementation in the workspace; it must establish the eager-finalization lifecycle (delete/move/idempotency-mark happen inside receive, before the Exchange is returned) that future implementors will follow.
  • WASM gains a sibling host function camel_poll(uri, timeout_ms). Plugins remain backward compatible (additive WIT imports). No versioned worlds for v1 — carto-kit is the only consumer and is pre-production.
  • The DSL strategy trait is named EnrichmentStrategy, not AggregationStrategy, to avoid collision with the existing EIP-22 AggregateStrategyDef family.