Adds support to delete old versions when successful deployment

[driverpt]

Which issue(s) does this change fix?

#7398

Why is this change necessary?

Because there's a limit on how many versions a Lambda has.

How does it address the issue?

Automatically deletes old version. Very useful when on SnapStart

What side effects does this change have?

None, it's disabled by default

Mandatory Checklist

PRs will only be reviewed after checklist is complete

• Add input/output type hints to new functions/methods
• Write design document if needed (Do I need to write a design document?)
• Write/update unit tests
• Write/update integration tests
• Write/update functional tests if needed
• make pr passes
• make update-reproducible-reqs if dependencies were changed
• Write documentation

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

[jysheng123]

Hi, Thanks for bringing up this PR. The code looks good to me so Ill run the approval workflow to get the testing process started, but can you also create an integration tests testing the happy path from beginning to end?

[jysheng123]

Can you also run make black to fix the formatting changes?

[lucashuy]

Thanks for opening this PR, left some comments. Additionally, we might want to consider adding this to the sam deploy command. This might need some more thought though if this makes sense to you and the team.

[lucashuy]

Will it ever be possible for this to be my_function:$LATEST? Just wanted to ask what happens if the Lambda alias resolved to the latest version of the function, and if deleting my_function:$LATEST just deletes the function.

[driverpt]

No, because there is no current alias. It only deletes old alias if there is an existing alias

current_alias_version is the lambda.get_alias operation. Does $LATEST qualify as an alias?

[lucashuy]

Hi @driverpt, just wanted to check in about the state of this PR and if you had the capacity to work on it or if there was anything you needed to move forward

[driverpt]

Hello. I can work on it. But I'm waiting on the CF Spec to be discussed

[lucashuy]

I've chatted with some team members, and the Metadata section is likely a better location, than inside of Properties. This won't require a spec change, and will only impact SAM CLI as the Metadata doesn't impact SAM transform. Having a CLI option was also brought up, but using an option here might make the UX a little messy in terms of deciding how we want to pass in function names into the option.

[mndeveci]

Hey @driverpt looking at the discussion here, I saw that recommendation is to use Metadata of the resources. Please let us know when you can follow-up with those changes, so that we can continue the review.

Thanks!

[hnnasit]

Hi @driverpt, following up to check if you were planning to make the above requested changes and had any questions the team could help with.

[driverpt]

Hello. Haven't yet had the time to implement this. I'll probably take a look at it this weekend

[mndeveci]

Thanks for your contribution, left a comment about one method response where you wrapped it up with str method.

[mndeveci]

Wrapping .get method response with str will cause None value to be returned as "None" (string), so the IF statement above will not work as intended.

Suggested change

	return str(
	self._lambda_client.get_alias(
	FunctionName=self.get_physical_id(self._function_identifier), Name=self._alias_name
	).get("FunctionVersion")
	)
	return self._lambda_client.get_alias(
	FunctionName=self.get_physical_id(self._function_identifier), Name=self._alias_name
	).get("FunctionVersion")

[dkphm]

Hi @driverpt is there any chance you can address this comment? Thanks!

[vicheey]

Hi @driverpt, thank you for your contribution.
We would like to circle back to the suggestion. Feel free to mention any of us here after you get a change to implement the change.