Create serverless applications | Create a long-running serverless workflow with Durable Functions

Question 1

What does it mean when a function is stateful?

Answer 1

It can retain state between function calls.

Question 2

Durable functions allows you to define stateful workflows using an orchestration function. An orchestration function provides these extra benefits:

Answer 2

You can define the workflows in code. You don’t need to write a JSON description or use a workflow design tool.

Functions can be called both synchronously and asynchronously. Output from the called functions is saved locally in variables and used in subsequent function calls.

Azure checkpoints the progress of a function automatically when the function awaits. Azure may choose to dehydrate the function and save its state while the function waits, to preserve resources and reduce costs. When the function starts running again, Azure will rehydrate it and restore its state.

Question 3

What is the Fan out/fan in pattern?

Answer 3

Fan out/fan in - This pattern runs multiple functions in parallel and then waits for all the functions to finish. The results of the parallel executions can be aggregated or used to compute a final result.