feat(eventbus): add idempotent consumer dedup primitive - #203
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Add a reusable consumer-side dedup toolkit so at-least-once consumers process an event exactly once. ProcessedEventStore keys dedup by (envelope id, consumer group); IdempotentEventProcessor claims first then runs the handler, propagating handler exceptions so the caller's transaction rolls back the claim and the event is retried. JdbcProcessedEventStore claims via INSERT ON CONFLICT DO NOTHING and participates in the ambient transaction; InMemoryProcessedEventStore serves tests and local dev. The store is wired by the consuming service, never auto-defaulted to in-memory in production. Covered by unit tests plus a Testcontainers-Postgres integration test for dedup, transactional rollback of the claim, and concurrent first-seen. Closes #192
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What
Consumer-side counterpart to the at-least-once producer/dispatcher: a reusable dedup primitive so consumers process each envelope exactly once. No consumer service exists yet, so this ships the generic, tested toolkit in
libs/fincore-eventbus; the per-serviceprocessed_eventsmigration lands with the first real consumer (E-02).ProcessedEventStore.markIfFirstSeen(envelopeId, consumerGroup)- dedup keyed by(envelope id, consumer group)so independent consumers each process an event once.IdempotentEventProcessor.process(envelopeId, consumerGroup, handler)- claim-then-handle: a thrown handler propagates so the caller's transaction rolls back the claim and the event is retried (exactly-once effect, never silent loss or double effect).JdbcProcessedEventStore-INSERT ... ON CONFLICT DO NOTHING, transaction-participating;InMemoryProcessedEventStorefor tests/dev. The store is wired by the consuming service - never auto-defaulted to in-memory in production (that would silently reprocess after a restart).processed-events.sqlDDL (PK(envelope_id, consumer_group)) for adopting services.Security
tableNameis the only interpolated SQL token (JDBC can't bind identifiers); it is validated at construction against^[A-Za-z_][A-Za-z0-9_]*$. All values are bound parameters.Gates
Local (
-x integrationTest, Docker down in WSL)::libs:fincore-eventbus:{test,detekt,detektTest,spotlessCheck,assemble,compileIntegrationTestKotlin}green. The Testcontainers-Postgres IT runs on CI: dedup, claim rolled back when the surrounding transaction rolls back (asserted in a separate transaction), and two concurrent transactions where exactly one wins first-seen. critic GO, code-reviewer APPROVE (2 must-fixes applied), security-auditor PASS, evaluator 0.89.spring-jdbcadded BOM-managed.Closes #192