13 Tricky AWS Simple Workflow Interview Questions

The full form of SWF is Simple Workflow. The purpose is to manage distributed application components. Here’re thirteen tricky interview questions to know about AWS SWF.

AWS SWF Service: Here are 13 Tricky Interview Questions
AWS SWF Service: Here are 13 Tricky Interview Questions

Let us say, your application has distributed components, Amazon SWF gives you full control over implementing and coordinating tasks without worrying about underlying complexities such as tracking their progress and maintaining their state.

Top Interview Questions

1. Do we need to implement workers in SWF Service?

Yes, you would need to implement.

2. What is a Task?

A task represents a logical unit of work that is performed by a component of your application.

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3. Where the workers run?

The workers run either on cloud (EC2) or in your local premises.

4. The real features of AWS SWF?

  • Amazon SWF gives you full control over implementing and coordinating tasks without worrying about underlying complexities such as tracking their progress and maintaining their state.
  • Amazon SWF stores tasks, assigns them to workers when they are ready, monitors their progress, and maintains their state, including details on their completion. 
  • To coordinate tasks, you write a program that gets the latest state of each task from Amazon SWF and uses it to initiate subsequent tasks.
  • Amazon SWF maintains an application’s execution state durably so that the application is resilient to failures in individual components. With Amazon SWF, you can implement, deploy, scale, and modify these application components independently.

5. What is Workflow in AWS SWF?

It is the place where you need to mention all the Distributed components. Each task relates to your distributed application called as activity.

6. What is Workflow Domain?

  • In terms of Workflow, Doman is a Space. The components present in one domain cannot interact with other domains.
  • Each domain has one or more tasks in it.

7. What is Workflow History?

It contains logs of all all the events happened related to workflow tasks.

8. What is ACTOR in AWS SWF?

It is a user written program. You can write it in all major computer programming languages.

9. The role of Actors?

Actors can be workflow starters, deciders, or activity workers. The actors can communicate with AWS SWF API.

10. What is Starter?

A workflow starter is any application that can initiate workflow executions. For example, one workflow starter could be an e-commerce website where a customer places an order. Another workflow starter could be a mobile application where a customer orders takeout food or requests a taxi.

11. What is Decider?

Activities within a workflow can run sequentially, in parallel, synchronously, or asynchronously. The logic that coordinates the tasks in a workflow is called the decider.

The decider schedules the activity tasks and provides input data to the activity workers.

The decider also processes events that arrive while the workflow is in progress and closes the workflow when the objective has been completed.

12. What is Activity worker?

An activity worker is a single computer process (or thread) that performs the activity tasks in your workflow.

13. What is Task List? And Long Polling?

A list is an organizer of Tasks that present in the SWF.

The Decider and Activity worker periodically communicate with SWF API. saying that they are alive to take tasks.

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Author: Srini

Experienced software developer. Skills in Development, Coding, Testing and Debugging. Good Data analytic skills (Data Warehousing and BI). Also skills in Mainframe.