Feat/use durable functions emulator image

[SilanHe]

Which issue(s) does this change fix?

#8488

Why is this change necessary?

This introduces a fix for the Homebrew linkage issue with the Durable Functions emulator. We are also introducing this so that SAM CLI can receive Durable Functions emulator updates uncoupled with SAM CLI release.

How does it address the issue?

We are automatically vending the emulator via an image published to ECR. See aws/aws-durable-execution-sdk-python-testing#196. Since the arm64 emulator is no longer included as an executable directly in the SAM CLI, this also fixed the issue where Homebrew users of SAM CLI could not emulate durable functions locally without doing some workaround.

What side effects does this change have?

As a bonus, this reduces the SAM CLI size.

Mandatory Checklist

PRs will only be reviewed after checklist is complete

• Review the generative AI contribution guidelines
• 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
• [n/a] Write/update integration tests
• [n/a] Write/update functional tests if needed
• make pr passes
• make update-reproducible-reqs if dependencies were changed
• [n/a] Write documentation

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

[yaythomas]

sam local invoke has a --invoke-image parameter, where customers can pass the location of a specific image to be used as the execution base image instead of the default Lambda base image.

https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-cli-command-reference-sam-local-invoke.html#ref-sam-cli-local-invoke-options-invoke-image

could explore using this established pattern rather than adding ENV_EMULATOR_IMAGE_TAG?

[SilanHe]

I think that is a good idea however due to time constraints I won't have any more capacity to work on this for a while so I'd be happy to have this as a follow up item. I'm guessing I'll have to confer with SAM CLI team for the name of the parameter, updating the docs, etc.

I don't think having it as an environment variable makes it substantially harder to use in the meantime.

[bchampp]

Personally I don't think this should be exposed as a new parameter on the CLI. Our expectation is for the latest image to always be "stable", so it should only be overridden in unexpected cases. The way I see this, having this be overridable at all is like a backdoor, and we shouldn't expect customers to need to use this.

Do you agree?

[SilanHe]

I ran integration tests locally

SAM_CLI_DEV=1 pytest tests/integration/local/invoke/test_invoke_durable.py::TestInvokeDurable -vv -s && SAM_CLI_DEV=1 pytest tests/integration/local/start_lambda/test_start_lambda_durable.py::TestStartLambdaDurable -vv -s && SAM_CLI_DEV=1 pytest tests/integration/local/start_api/test_start_api_durable.py::TestStartApiDurable -vv -s

and they all passed

[valerena]

LGTM. Waiting for the final official image location.

[bchampp]

Nice - I much prefer this approach, 1 blocking comment about the --lambda-endpoint and two minor suggestions.

[roger-zhangg]

LGTM