Is it possible to integrate AWS SNS and AWS SQS FIFO queue

Question

With the introduction of FIFO queues in SQS we are guaranteed that SQS messages will be delivered in order.

Now, could there be an out-of-order delivery when I publish messages through SNS? Here's what I'm thinking that could happen:

 _____                       _____                       __________
| App |-- Publish msg 1 --> | SNS | --> Queue msg 2 --> | FIFO SQS | --> Consume 2
|     |-- Publish msg 2 --> |     | --> Queue msg 1 --> |          | --> Consume 1
 -----                       -----                       ----------

Is that scenario possible?

Answer 1

This scenario is currently impossible because SNS is not compatible with FIFO SQS in AWS. It is only supported for standard queues. This is clearly mentioned in the AWS docs in this link, under special notes.

EDIT

It's also listed in the SNS FAQs, under Are Amazon SQS FIFO queues compatible with Amazon Simple Notification Service (SNS)?

The answer's still the same as of July 26, 2020: Amazon SNS does not currently support forwarding messages to Amazon SQS FIFO queues. You can use SNS to forward messages to standard queues.

Answer 2

SNS FIFO just launched. SNS can now integrate with SQS FIFO https://aws.amazon.com/blogs/aws/introducing-amazon-sns-fifo-first-in-first-out-pub-sub-messaging/

Answer 3

It is possible with the latest SNS support for FIFO,

As per the excerpt from amazon doc

FIFO topics support fanning out messages to multiple subscriptions with high durability, filtering, encryption, and privacy, while FIFO topics provide the added benefit of ordering and deduplication of message

I have listed some important links for you to refer

1. Amazon SNS introduces First-in-First-out (FIFO) topics with strict ordering and deduplication of messages
2. Introducing Amazon SNS FIFO – First-In-First-Out Pub/Sub Messaging
3. Building event-driven architectures with Amazon SNS FIFO

As your SNS topic protocol endpoint is Amazon SQS which perfectly works fine.

NOTE for other protocol endpoints Ref

• Currently, the endpoint protocol must be Amazon SQS, with an Amazon SQS FIFO queue's Amazon Resource Name (ARN) as the endpoint.
• SNS FIFO topics can't deliver messages to customer managed endpoints, such as email addresses, mobile apps, phone numbers for text messaging (SMS), or HTTP(S) endpoints. These endpoint types aren't guaranteed to preserve strict message ordering. Attempts to subscribe customer managed endpoints to SNS FIFO topics result in errors.