Routing messages from Amazon SNS to SQS with filtering

15
votes

In RabbitMQ, one can create an exchange, then bind it to multiple queues, each with a routing key. This enables messaging architectures like this:

           message_x
         /    |     \
foo-msg_q  bar-msg_q  msg-logger_q

Clients publish messages to the message_x exchange, which routes only messages with routing key "foo" to the foo-msg_q queue, only messages with the routing key "bar" to the bar-msg_q queue, and all messages to msg-logger_q queue.

I'm having trouble figuring out how to do this in AWS. My first thought was to set up permissions on the individual queues to accept messages based on subject, but the only available fields for permission conditions are:

  • aws:CurrentTime
  • aws:EpochTime
  • aws:MultiFactorAuthAge
  • aws:principaltype
  • aws:SecureTransport
  • aws:SourceArn
  • aws:SourceIp
  • aws:UserAgent
  • aws:userid
  • aws:username

None of these seem like they can be influenced by any message I publish to the message_x topic.

Is it possible to doing something like this when using Amazon Simple Notification Service to fan out to multiple Simple Queue Service queues, with each queue receiving a subset of messages published to the topic?

2
amazon-web-servicesamazon-sqsamazon-sns
@OlivierAlbertini That's not very helpful. If you noticed above, I mentioned that this is something you can do in RabbitMQ, so I know there are other platforms that have this functionality. I asked specifically about SNS / SQS. – Josh Glover
Did you find any elegant way to solve your problem ? – vercin
SNS filtering like described above is now available ... see below answer by @puji – Mike Atlas
This blog is very useful: medium.com/better-programming/… – mealesbia

2 Answers

25
votes

This is possible by using message attribute filtering in SNS. After you subscribe different SQS queues to an SNS topic, you can specify attributes to filter on by using the SNS API SetSubscriptionAttributes. This will allow messages with different attributes to get routed to the correct SQS queue.

This is also not limited to SQS queues but any subscription sources on a SNS topic. For example, a single SNS topic can publishing one set of messages to Lambda, and another set to SQS.

SDK Reference: http://docs.aws.amazon.com/sns/latest/api/API_SetSubscriptionAttributes.html

More details are given here with examples: https://aws.amazon.com/blogs/compute/simplify-pubsub-messaging-with-amazon-sns-message-filtering/

7
votes

EDIT

I cannot delete an accepted answer, so see the answer below for the now correct answer since this feature has been released.

Original (now incorrect) Answer (for posterity):

No it's not possible. Would be a great feature for them to add though.

The only alternative I know is to create a topic for each routing rule and then publish to the correct topic. It's not pretty, but it accomplishes the task. If you have a lot of rules, you might need more than the 3000 topics they allow. You can request an increase in topic limit from AWS on their website by following the instructions here http://docs.aws.amazon.com/general/latest/gr/aws_service_limits.html#limits_ses_quota.