One citizen upload event must notify virus scan, thumbnail, and archive services without the uploader calling each consumer directly. Which pattern best fits?
Select an answer to reveal the explanation.
Short Explanation
Fan-out is the town crier: shout the upload once and every interested service hears it. The uploader should not dial virus scan, thumbnails, and archive one by one. One event, many listeners—cleaner and safer.
Full Explanation
Fan-out distributes a single event or message to multiple subscribers so producers need not invoke each consumer synchronously. Messaging or event buses commonly implement this pattern for post-upload pipelines. Direct SSH chaining, ephemeral local-only storage, and manual notification do not provide reliable multi-consumer distribution.