Custom resource id for AwsCustomResource lambda function

[emfrab]

I have this piece of code that I adapted from somewhere to allow me to get SSM parameters from another region:

class SSMParameterReader(AwsCustomResource):
    def __init__(self, scope: Construct, name: str, role: iam.IRole, function_name: str):
        ssm_aws_sdk_call = AwsSdkCall(service="SSM",
                                      action="getParameter",
                                      parameters={"Name": "MY_PARAMETER"},
                                      region="us-east-1",
                                      physical_resource_id=PhysicalResourceId.of(props.parameter_name))

        policy = AwsCustomResourcePolicy.from_statements([iam.PolicyStatement(resources=["*"],
                                                                              actions=["ssm:GetParameter"],
                                                                              effect=iam.Effect.ALLOW)])

        super().__init__(scope, name, function_name=function_name, on_update=ssm_aws_sdk_call, role=role, policy=policy)

    @property
    def value(self):
        return self.get_response_field("Parameter.Value")

this is invoked in my stack like this:

param_reader = SSMParameterReader(self, "MyParameterReader",
                                  role=my_lambda_role,
                                  function_name="my-custom-resource-function")

it all works fine, but I get this into my synthesized cloudformation template:

"AWS679f53fac002430cb0da5b7982bd22872D164C4C": {
   "Type": "AWS::Lambda::Function",
   "Properties": {
    "Code": {
     "S3Bucket": "cdk-hnb659fds-assets-1111111111-eu-west-1",
     "S3Key": "dg546rea583gdf3ga2fdg1aeaf25g1we5365hj2gw23f1g.zip"
    },
    "FunctionName": "my-custom-resource-function",
    "Handler": "index.handler",
    "Role": {
     "Fn::GetAtt": [
      "MyLambdaRole55C9D0CA",
      "Arn"
     ]
    },
    "Runtime": "nodejs18.x",
    "Timeout": 120
   },
   "DependsOn": [
    "MyLambdaRole55C9D0CA"
   ],
   "Metadata": {
     ...
   }
  }

Is there any way I can customize the resource name? i.e AWS679f53fac002430cb0da5b7982bd22872D164C4C into something more meaningful.

Thanks!

[emfrab]

this might be related to #19309

[peterwoodworth]

Hey, I'm curious if there's any specific issue with the current logical ID name. These names are only identifiers for CloudFormation, they generally don't need to be that descriptive unless you need to inspect the template

That said, you could use an aspect on the provider resource. Take the following as an example:

const app = new cdk.App();
const stack = new TestingStack(app, 'TagVisitStack', {
  env: { account: process.env.CDK_DEFAULT_ACCOUNT, region: 'us-east-1' },
});

class LogicalIdModifier implements cdk.IAspect {
  public visit(node: IConstruct): void {
    if (!(node instanceof cdk.CfnResource)) return;
    (node as cdk.CfnResource).overrideLogicalId(`CustomResourceProvider${node.node.addr}`);
  }
}

cdk.Aspects.of(stack.crProvider).add(new LogicalIdModifier());

---

export class TestingStack extends cdk.Stack {
  public crProvider: lambda.Function;
  constructor(scope: Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    new cr.AwsCustomResource(this, 'CustomResource', {
      onCreate: {
        service: 'S3',
        action: 'putObject',
        physicalResourceId: cr.PhysicalResourceId.of('CustomResource'),
      },
      policy: cr.AwsCustomResourcePolicy.fromSdkCalls({ resources: cr.AwsCustomResourcePolicy.ANY_RESOURCE }),
    });

    this.crProvider = this.node.children.find((child) => child instanceof lambda.Function && child.node.id.startsWith('AWS')) as lambda.Function;
  }
}

If you just want to change the id of the function and not of all the children of the function, you could forego the aspect and instead just add this in your stack

    const providerFn = this.node.children.find((child) => child instanceof lambda.Function && child.node.id.startsWith('AWS')) as lambda.Function;
    (providerFn.node.defaultChild as lambda.CfnFunction).overrideLogicalId('CustomResourceLambda');

[emfrab]

there's no specific issue, it's just a matter of consistency with all the other resources. And partly because I like to be able to look at the stack and easily see and understand all its components.

But if the only one is by overriding it this way, then maybe laving it as is. Anyways, thank you as always for your help :)