A Durable Functions orchestrator calls three activities one after another on a Premium plan. The middle activity may run for several minutes. What must be configured so that this activity is not cut off early?
Show answer and explanation
Answer: A
The functionTimeout value in host.json sets how long a function execution may run before the host terminates it, and it applies to activity functions as well. On Consumption the default is five minutes with a maximum of ten. On Premium the default is thirty minutes and the limit can be raised further, so a longer activity needs this value set above its worst-case duration.
Why the other options are wrong
- B. Wrapping the activity in an HTTP trigger removes it from the durable pattern, so the orchestrator loses checkpointing and retries, and the same timeout limit still applies to the function.
- C. Entity functions hold small pieces of state for coordination. They do not extend how long an activity may run, so the middle step would still be terminated at the host limit.
- D. The external event wait timeout controls how long an orchestrator waits for an outside signal. It does not govern how long an activity function may execute, so the cut-off would remain.