Ability to get stack region & account ID from backend resources

[dreamorosi]

Environment information

System:
  OS: macOS 15.1.1
  CPU: (12) arm64 Apple M2 Pro
  Memory: 137.39 MB / 32.00 GB
  Shell: /bin/zsh
Binaries:
  Node: 20.12.2 - ~/.local/state/fnm_multishells/13709_1732902102431/bin/node
  Yarn: 1.22.22 - ~/.local/state/fnm_multishells/13709_1732902102431/bin/yarn
  npm: 10.5.0 - ~/.local/state/fnm_multishells/13709_1732902102431/bin/npm
  pnpm: 9.6.0 - ~/.local/state/fnm_multishells/13709_1732902102431/bin/pnpm
NPM Packages:
  @aws-amplify/auth-construct: 1.5.0
  @aws-amplify/backend: 1.8.0
  @aws-amplify/backend-auth: 1.4.1
  @aws-amplify/backend-cli: 1.4.2
  @aws-amplify/backend-data: 1.2.1
  @aws-amplify/backend-deployer: 1.1.10
  @aws-amplify/backend-function: 1.8.0
  @aws-amplify/backend-output-schemas: 1.4.0
  @aws-amplify/backend-output-storage: 1.1.3
  @aws-amplify/backend-secret: 1.1.5
  @aws-amplify/backend-storage: 1.2.3
  @aws-amplify/cli-core: 1.2.0
  @aws-amplify/client-config: 1.5.2
  @aws-amplify/deployed-backend-client: 1.4.2
  @aws-amplify/form-generator: 1.0.3
  @aws-amplify/model-generator: 1.0.9
  @aws-amplify/platform-core: 1.2.2
  @aws-amplify/plugin-types: 1.5.0
  @aws-amplify/sandbox: 1.2.6
  @aws-amplify/schema-generator: 1.2.5
  aws-amplify: 6.10.0
  aws-cdk: 2.171.1
  aws-cdk-lib: 2.171.1
  typescript: 5.7.2
CDK environment variables:
  CDK_DOCKER = finch

Describe the feature

When working with many CDK resources, it's useful to have access to the region and account ID of the stack where I'm deploying my Amplify app.

Hardcoding these values can be problematic at times, so ideally I'd like to be able to interpolate these values, similar to what I can do already in CDK.

Ideally, I'd like to be able to do something like this or similar to this:

import { defineFunction, stack } from "@aws-amplify/backend";

export const myFunction = defineFunction({
  name: "my-function",
  layers: {
   "@aws-lambda-powertools/*":
      `arn:aws:lambda:${stack.region}:${stack.account}:layer:myLayer:12`,
  },
});

alternatively, I'd like to be able to use a regular CloudFormation variable and have Amplify leave it as-is in the final stack:

import { defineFunction, stack } from "@aws-amplify/backend";

export const myFunction = defineFunction({
  name: "my-function",
  layers: {
   "@aws-lambda-powertools/*":
      "arn:aws:lambda:\${AWS::Region}:123456789012:layer:myLayer:12"
  },
});

Use case

For example, when working with Lambda layers, customers need to specify the ARN of the layer they want to attach to a function. These ARNs need to be in the same region where the function is being deployed.

Hardcoding the region makes the stack not portable.

[ykethan]

Thank you for filing this, marking this as feature request for further improvements.