(SAM): update the SAM specification version used in the CDK

[skinny85]

We need to update the version of the SAM spec we use in the CDK. We are missing new properties, like PackageType in AWS::Serverless::Function, and some properties that we mark as required (like CodeUri of AWS::Serverless::Function) are no longer required.

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(Additional data from related issues)

We currently download the spec from a repo called awslabs/goformation -

aws-cdk/packages/@aws-cdk/cfnspec/build-tools/update.sh

Line 58 in 9f8de62

"https://raw.githubusercontent.com/awslabs/goformation/master/generate/sam-2016-10-31.json" \

Unfortunately, it seems that there is no machine readable SAM spec available officially - aws/serverless-application-model#1133. We need a better way to keep the SAM spec up to date with the latest, but without any machine-readable spec, this becomes a fairly difficult problem to stay on top of.

In the meantime, raw property overrides allow users to use missing properties, and missing resources can be created using CfnResource.
Neither of these are ideal, and we apologize for the current poor experience here.

[skinny85]

Reference docs: https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-resource-function.html#sam-function-packagetype

[dannyoboy]

Hi, I'm not sure if this is the right place to point this out, but it is relevant to the issue. The AWS::Serverless::Function property DeploymentPreference has a Hooks property that is specified as a list of strings in cdk. However, the cloud formation docs let you specify between pretraffic and posttraffic hooks: https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-property-function-hooks.html. Currently, I don't think there's a way to specify pretraffic vs posttraffic hooks for DeploymentPreference in cdk.

[github-actions]

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[siarhei-klimuts]

Can not migrate my SAM template to CDK.

My SAM template works great, CodeUri of my functions point to local directories.
When using CfnInclude with the template, cdk synth looks good, but during cdk deploy on step creating CloudFormation changeset deploy fails with error: "'CodeUri' is not a valid S3 Uri of the form 's3://bucket/key' with optional versionId query parameter"

[skinny85]

Can you show what codeUri is in your template?

[siarhei-klimuts]

Sure

CodeUri: ./notifications

[skinny85]

Right. So I think this works because the SAM CLI does the packaging for you. In the CDK, you need to turn that directory into an Asset. I show how to do that in this video: https://youtu.be/bTC8XV5aLTo?si=3fdUJ_T1_cgXzejL

[siarhei-klimuts]

Right. So I think this works because the SAM CLI does the packaging for you. In the CDK, you need to turn that directory into an Asset. I show how to do that in this video: https://youtu.be/bTC8XV5aLTo?si=3fdUJ_T1_cgXzejL

Thank you! This is exactly what I needed.

But I stuck with another issue related to migration:
CfnInclude had no issues parsing my functions with Metadata: BuildMethod: makefile
But when I try to deploy my CDK stack I see that my functions code have not been built as it configured in the Makefile
So it looks like cdk deploy ignores Makefile.

Is it intendent?
Should I build function code firs and then create Asset on a built code?

[skinny85]

Right. So I think this works because the SAM CLI does the packaging for you. In the CDK, you need to turn that directory into an Asset. I show how to do that in this video: https://youtu.be/bTC8XV5aLTo?si=3fdUJ_T1_cgXzejL

Thank you! This is exactly what I needed.

But I stuck with another issue related to migration: CfnInclude had no issues parsing my functions with Metadata: BuildMethod: makefile But when I try to deploy my CDK stack I see that my functions code have not been built as it configured in the Makefile So it looks like cdk deploy ignores Makefile.

Is it intendent? Should I build function code firs and then create Asset on a built code?

Yes. CDK Assets don’t use the Metadata in any way (this is another SAM feature), so you need to build your Lambda code separately. There is a “build” key that you can set in your cdk.json file for this purpose.