Challenge · intermediate · 25 min · Premium
The retry that shipped two pumps
Calder shipped two pumps for one approved replacement after a network blip: the worker retried with a new key. Find the key shape that made the retry a new request, fix it, and show the service refusing a changed payload under the same key.
Brief
- Customer
- Calder Equipment (synthetic customer from the Production AI Agents course; every request, key and receipt on this box is made up for the exercise)
- Situation
- At 04:12 the action worker's first request for case C12 timed out reading the response. It retried at 04:13 and got a 201. The warehouse shipped two pumps. The replacement service's log shows two accepted requests for C12 with different idempotency keys, one minute apart.
- Your role
- You are the FDE who owns the worker's key policy. You have the service log, the worker config (bound to the live queue's consumer), the contract, and curl against the service simulator.
- Goal
- Name why the retry created a second request, fix the key so a retry replays the original, prove it with two identical sends, and show what the service does when the payload changes under the same key.
Objectives
- 1.Name why the retry created a second request (you commit to an answer)
- 2.Make the worker use one key per logical action
- 3.Prove replay: send the same request twice under the per-action key and get the original receipt back
- 4.Show what the service does when the payload changes under the same key
Mission workspace
This mission is part of premium, with every challenge and incident in the lab. The brief above is the whole problem; the box, the hints and the debrief are what you unlock.
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