Parallel enrichment Functions must finish before the city enqueues the final summary job. What coordination pattern fits?
Select an answer to reveal the explanation.
Short Explanation
Fan-in is waiting for every inspector’s clipboard before the chief writes the summary—parallel enrichments check in, then the final job queues.
Full Explanation
When parallel enrichment Functions must finish before the city enqueues the final summary job, use a fan-in coordination pattern: track completion of each enrichment (Durable Functions task fan-in, aggregator, or completion messages), then enqueue the municipal summary only after all required inputs exist. Fan-in prevents summaries built on partial inspector or data enrichments.
Enqueueing the final summary immediately before any enrichment starts guarantees incomplete context. Running enrichments with no completion signal forces guessing and race conditions. Cancelling all parallel enrichments when one finishes early throws away useful municipal work and still does not define a correct join.
Exam caveat: fan-out/fan-in is a core Durable Functions and messaging composition pattern for AI pipelines—fan-out starts parallel enrichments; fan-in joins results before downstream generative summary. Ordinary queues alone need an explicit aggregator to achieve the same join semantics.
Operational check: start three enrichment activities for a test case, assert the summary message is absent until all three complete, then verify a single summary job enqueues with merged outputs and token spend for the summary occurs only after the join.