[DEVELOPER] SQS + SNS

Question 1

Explain how SQS Extended Client works

Answer 1

Question 2

Say you want to send a message through SQS of 1GB. How might you do this?

Answer 2

SQS Extended Client

Question 3

Why is SQS Long Polling preferable to Short Polling?

Answer 3

increases efficiency and latency of the application by decreasing number of API calls made to SQS

Question 4

What are the configuration limits for wait time for SQS Long Polling?

Answer 4

1-20 seconds, (but 20 seconds is preferred)

Question 5

What is the name API-level field for configuring SQS Long Polling?

Answer 5

RecieveMessageWaitTimeSeconds

Question 6

What does the SQS API call PurgeQueue do?

Answer 6

delete all messages in the queue

Question 7

Suppose you are using an SQS/SNS fan-out pattern for an ordering service, but one of your SQS queues should only receive messages that are of the “placed” state. There are multiple SQS queues and you expect not all of your incoming messages will have a “placed” state. How can you implement this functionality?

Answer 7

Use SNS Message Filtering (aka fitler policies)

Question 8

Suppose you want to send one S3 Event to many SQS queues. How can you do this in S3?

Answer 8

You cant do it in S3, because for each (event type, prefix) you can only have 1 S3 event rule

Instead Use SNS/SQS Fan-out (configure events to SNS)

Question 9

Suppose you want to configure your messaging system to have ordering, deduplication, and fan-out. How can you accomplish this?

Answer 9

SNS FIFO Topic AND SQS FIFO Queue

Question 10

Can Lambda subscribe to an SNS FIFO Queue?

Answer 10

NO

only SQS FIFO can subscribe to an SNS FIFO topic

Question 11

What are the two methods for SQS FIFO deduplication?

Answer 11

1. Explicit MessageDeduplicationID
2. Content-based Deduplication (a SHA-256 of the message body)

Question 12

Suppose you have an SQS queue in one account and an EC2 instance in another account that needs to poll from that SQS queue. How can you configure this to happen?

Answer 12

Apply an SQS Queue Policy on the queue to give ReceiveMessage permissions to the account with the EC2 instance

Question 13

Suppose you want to publish an S3 event notification to an SQS queue. You check the SQS queue but the messages are not showing up there. What might you need to do?

Answer 13

Configure an SQS Queue Policy on the queue to give SendMessage permissions to the S3 Bucket

Question 14

Suppose you want to send one S3 Event to many SQS queues. How can you do this?

Answer 14

Use SNS/SQS Fan-out (configure events to SNS)

S3 Event -> SNS -(fan out) -> SQS queues

Recall: for each (event type, prefix) you can only have 1 S3 event rule