You are developing a data processing solution using Azure Durable Functions. You need to sequence the execution flow of the application during a standard function chaining scenario. Arrange the actions in the correct chronological order from start to finish.
- 1An HTTP-triggered client function starts a new instance of the orchestrator function.
- 2The orchestrator function executes until it reaches an await statement for the first activity function, then yields control.
- 3The first activity function runs to completion and saves its output to the task history table.
- 4The orchestrator function wakes up, replays its execution history to restore state, and schedules the next activity function.
Answer
The correct chronological sequence is: first, the client function starts the orchestrator instance; second, the orchestrator executes and yields control at the first await statement; third, the activity function runs to completion and saves its result; and finally, the orchestrator wakes up, replays history, and schedules the next activity function.
In Durable Functions, the workflow is initiated by a client function. When the orchestrator executes, it schedules tasks and yields control (goes to sleep) when awaiting asynchronous activities. The activity runs independently and stores its state. Once complete, the orchestrator wakes up and replays the history to reconstruct its state, allowing it to schedule the next step without maintaining an in-memory active state.
Step-by-Step Solution
Key Concept
Azure Durable Functions Execution Lifecycle and Replay Mechanism