feat: Add an existing SQS queue option to SNS event

[53ningen]

readable diff:
https://github.com/awslabs/serverless-application-model/pull/1231/files?w=1

Issue #, if available:
#854

Description of changes:
Add an existing SQS queue option to SNS event

Description of how you validated changes:

• make pr
• verify transformed template deploys and application functions as expected

Checklist:

• Write/update tests
• make pr passes
• Update documentation
• Verify transformed template deploys and application functions as expected
• Add/update example to examples/2016-10-31

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-io]

Codecov Report

Merging #1231 into develop will decrease coverage by 0.02%.
The diff coverage is 93.1%.

@@             Coverage Diff             @@
##           develop    #1231      +/-   ##
===========================================
- Coverage    94.61%   94.59%   -0.03%     
===========================================
  Files           78       78              
  Lines         4252     4271      +19     
  Branches       844      846       +2     
===========================================
+ Hits          4023     4040      +17     
- Misses         110      111       +1     
- Partials       119      120       +1

Impacted Files	Coverage Δ
samtranslator/model/eventsources/push.py	90.82% <93.1%> (-0.06%)	⬇️

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[53ningen]

this PR is now ready for review

[53ningen]

if isinstance(self.SqsSubscription, bool) is True, then self.SqsSubscription is always True, because we checked if self.SqsSubscription is False on L388

[ShreyaGangishetty]

@53ningen Thank you for contributing this feature!! This looks great. I have minor comments about adding a unit test and also on throwing errors when QueueArn or QueueUrl are not given.
Could you please add/update any of the existing unit tests for a condition where SqsSubscritption: False.

[timoschilling]

The informations of QueueArn and QueueUrl seams to be redundant. Isn't it possible to build the QueueUrl from the QueueArn, so that we only need to configure one of them?

[chrisoverzero]

@timoschilling Gominingen described why this was sometimes not possible (and why a separate URL can be a feature) back in the original issue. In short, QueueArn is rarely going to be a string. It will almost always be an object with a key of Fn::GetAtt.

I can imagine that and similar being features of the next round of the, uh, feature:

• If no QueueUrl specified:
  • If QueueArn is string, construct URL as string.
  • If it is Fn::GetAtt object, get logical ID, construct Ref object.
  • Bail on other intrinsics.

…which sound like really nice checks, assuming I haven’t forgotten why they’re impossible.

[53ningen]

Could you please add/update any of the existing unit tests for a condition where SqsSubscritption: False.

I've added on this line.

[53ningen]

@ShreyaGangishetty
Thank very much you for reviewing this PR and I'm sorry for my late response.
I have addressed your pull request comments.

Ready for review again.

[ShreyaGangishetty]

@53ningen Thank you for addressing my comments. This PR looks good to me!!

[praneetap]

Thanks a ton for submitting this feature!

[ljacobsson]

What's the status on this?

It looks like it was included in the v1.20.0 release, but I can't get it working and failing on this line. I've even tried to define both QueueArn and QueueUrl

Also, there's no sign of this feature in the documentation.

[chrisoverzero]

Also, there's no sign of this feature in the documentation.

It is in the documentation and specification.