[assets] cdk synth should package assets in s3 bucket and synthesized template references those assets

CFN & SAM as set a precedence in how people deploy their infrastructure in the cloud. We package the artifacts, a template is returned that references the packaged artifacts and it ready for deploy.

The CDK can follow a similar approach. This makes it easier and less complex in working with serverless applications that have many lambda functions.

Use Case

Many applications take a serverless microservice approach. Where you will have a service with many lambda functions. Currently, the way that it is handled in the cdk is complicated and brittle at the moment.

eg.

export class SomeMicroserviceStack extends cdk.Stack {
  constructor(scope: cdk.App, id: string, props: SomeMicroserviceStackProps) {

    public readonly lambdaCode1: CfnParametersCode; 
    public readonly lambdaCode2: CfnParametersCode; 
    // n number of readonly properties with reference to lambda functions in microservice

    super(scope, id, props);
          // multi lambda functions
    }
}

Then we have the pipeline

export class PipelineStack extends Stack {
    constructor(scope: cdk.App, id: string, props: PipelineStackProps) {
        super(scope, id, props);

        const paymentServiceDevDeployAction = new CloudFormationCreateUpdateStackAction({

            actionName: "PaymentServiceStack_DEV_Deploy",
            templatePath: servicesBuildOutput.atPath(
            "SomeMicroserviceStack.template.json"),
            stackName: "SomeMicroserviceStack",
            adminPermissions: true,
            account,
            region,
            parameterOverrides: {
            ...props.lambdaCode1.assign(lambda1Output.s3Location),
            ...props.lambdaCode2.assign(lambda2.s3Location),
            // n number of lambdas
            // limit of 1KB
            // For every new lambda function it gets added which becomes a pain
            },
            extraInputs: [lambda1Output, lambda2, .....],
        });
    }
}

Proposed Solution

I believe its more straight forward to have the cdk package the artifact in a user defined bucket and out put to us a parsed template where the artifacts are referenced.

I am taking the concept from SAM. Where we have the command: sam package --template-file PATH --s3-bucket TEXT

so for cdk we would have cdk synth/package [Stack] --s3-bucket TEXT

The output from that command can be used to do a deploy directly or be used in a ci/cd workflow.

Other

• 👋 I may be able to implement this feature request
• ⚠️ This feature might incur a breaking change

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This is a 🚀 Feature Request

[shivlaks]

@eladb I like the idea of adding cdk package as well outside of synth. I’m not sure if @rix0rrr had any other ideas / thoughts

[eladb]

We should be able to provide a way to package assets and upload them now that we’ve decoupled assets from deployment into a new tool called cdk-assets.

I am not opposed to adding cdk package which will synthesize the template and run cdk-assets to bundle and publish assets to their needed location.

At any rate, this is a separate step from synth.

Copy @rix0rrr

Reassigning to @shivlaks