DATA SYSTEMS / KAFKA FIELD LAB
Проектируйте event contracts и consumer policies, запускайте их на детерминированном broker fixture и защищайте delivery semantics по наблюдаемым offsets.
CASE / EVENT CONTRACT / KEY / IDEMPOTENT PRODUCER
Three transitions of order ord-42 must remain ordered while unrelated orders scale across partitions. Repair the event envelope, topic contract, partition key and producer durability settings.
01 / GUARANTEES
Publish versioned, traceable events and preserve aggregate order without claiming a total order for the topic.
Kafka appends records in offset order inside one partition. A stable aggregate key keeps transitions that must be ordered together; more partitions add parallelism, not one global order. The lab uses a documented deterministic training hash, so only key stability—not a particular partition number—is the contract.
In Kafka 4.3 idempotence requires acks=all, retries above zero and at most five in-flight requests per connection. It prevents retry duplicates in the Kafka log; it does not make a database write and event publish one application transaction.
topic · partitions · partition_key · producer · events[]
02 / POLICY
Запустите manifest. Simulator не подключается к cluster и не обещает network timing; он воспроизводимо проверяет явно названные Kafka и application invariants.