AWS Application Service Flashcards
What is SWF ?
The fundamental concept in Amazon SWF is the workflow. A workflow is a set of activities that carry out some objective, together with logic that coordinates the activities. For example, a workflow could receive a customer order and take whatever actions are necessary to fulfill it.
What is Amazon SES ?
Amazon SES (Simple Email Service) is an email platform that provides an easy, cost-effective way for you to send and receive email using your own email addresses and domains.
What is Amazon SNS ?
Amazon Simple Notification Service (Amazon SNS) is a web service that coordinates and manages the delivery or sending of messages to subscribing endpoints or clients. In Amazon SNS, there are two types of clients—publishers and subscribers—also referred to as producers and consumers.
What happen when you create an Topic on AWS SNS ?
A ARN (Amazon ressource Name) is created.
What is the difference between AWS SNS and SQS ?
SNS is a push notification service, while SQS is a message system that require worker node to poll the queue.
What application service allows you to decouple your infrastructure using messaged based queues?
SQS
What does a “domain” refer to in Amazon SWF?
A collection of Workflow.
By default, EC2 instances pull SQS messages from an SQS queue on a FIFO (First In First out) basis ?
False (can be FIFO now, but otherwise it’s not guarantee).
Amazon’s SQS service guarantees a message will be delivered at least once.
True, can be deliver more than once especially if not setup correctly according to process time.
Amazon SWF ensures that a task is assigned only once and is never duplicated. ?
True
Amazon SWF is only for programme ressources ?
No it can be human interaction as well for exemple.
What the maximum size of a message in SQS ?
256 KB
How long a message can be kept in SQS ?
From 1 mn to 14 days, default is 4 days.
What is visibility timeout in SQS ?
When a message is picked up for processing but processing fail to return on time, then after the visibility timeout has be reach, the message will be back into the queue.
What is the visibility timeout maximum for SQS ?
12 hours.
What is SQS long polling ?
It’s a polling mechanism that prevent the need to pull constantly, it can pull and the callback can wait for hoours until call back. With normal pulling lot of request need to be made and so imply higher cost.
Is AWS SWF keep log of task and event ?
Yes, in opposite for SQS it need to be done on an application level.
What is the different 3 actors of SWF ?
Workflow starter (for exemple website or app). Decider (control the flow), decide what to do next. Activity workers, make the job (can be anything like human).
What the different subscriber with SNS ? (7)
HTTP HTTPS Email Email-JSON SQS Application Lambda