Support for custom resources

[udondan]

I tried cdk-dia today and it looks great. One thing I noticed is, it skips custom resources.

Already tried to look into this but it appears this is not so easy to implement. I haven't figured out where custom resources are filtered from generation. Adding them to the awsResouceIconMatches.json seems to not fix it (it would not be a solution anyway, since the name isn't static. Just did that for a quick test) Somehow they're filtered before they reach the AwsIconSupplier.matchIcon() call but I was not able to figure out how this morning.

[udondan]

If I understand the code in 6d689c3 correct, it looks for AWS::CloudFormation::CustomResource. That's one way to define custom resources. The other way is Custom::xxx where the xxx can be any string.

For my custom resources it looks more like this:

{
  "Resources": {
    "TestKeyPairEC2KeyPairtestkeypair8B76C420": {
      "Type": "Custom::EC2-Key-Pair",
      "Properties": {
        "ServiceToken": {
          "Fn::GetAtt": [
            "EC2KeyNameManagerLambdaBE629145",
            "Arn"
          ]
        },
        "Name": "test-key-pair",
        "Description": "A test Key Pair",
        "KmsPrivate": "alias/aws/secretsmanager",
        "KmsPublic": "alias/aws/secretsmanager",
        "StorePublicKey": false,
        "ExposePublicKey": true,
        "RemoveKeySecretsAfterDays": 0,
        "SecretPrefix": "ec2-ssh-key/",
        "StackName": "EC2KeyPair",
        "Tags": {
          "a": "b",
          "c": "d",
          "CreatedByCfnCustomResource": "CFN::Resource::Custom::EC2-Key-Pair",
          "Hello": "World"
        }
      },
      "UpdateReplacePolicy": "Delete",
      "DeletionPolicy": "Delete",
      "Metadata": {
        "aws:cdk:path": "EC2KeyPair/Test-Key-Pair/EC2-Key-Pair-test-key-pair/Default"
      }
    }
     ...
  }

This is from one of my custom constructs cdk-ec2-key-pair.

[pistazie]

cdk-dia generates a diagram from the construct-tree (./cdk.out/tree.json). It doesn't parse the actual cloudformation template so it can't search for Custom::xxx.

looks like the CDK team built a "custom resource framework" and it's being processed after the construct-tree is generated.
therefore my solution was (what the commit does) is to identify "constructInfo": { "fqn": "@aws-cdk/core.CustomResource", "version": "1.102.0" } and converts it to a AWS::CloudFormation::CustomResource so it's in the diagram.

What would your best-case diagram for the construct look like?

In my opinion, constructs should usually be collapsed by default so the diagram contains one node/icon with a label "test-key-pair custom resource" and the construct's implementation is abstracted (the user used a construct library). reaching this result with your construct is tricky because some of the resources are binded to the construct (e.g. new cdk.CustomResource(this,...) and some resources are "leaked"/binded to the stack? (e.g. new iam.ManagedPolicy(stack, ...).

Additionally, in order to collapse constructs I used a convention used by cdk where the "main" resource of each construct is has the id resource.

When one uses cdk-dia with the --collapsed false flag then the construct should be a cluster (basically a frame) with all provisioned resources inside it.