AWS CloudFormation の AWS::EKS::Cluster から OIDC プロバイダーの URL を取得するにはどうすればよいですか?

Parameters:
  EKSClusterName:
    Type: String
    Description: Provide the name for EKS Cluster
Resources:
  ClusterName:
      Type: Custom::ClusterName
      Properties:
        ServiceToken: !GetAtt LambdaFunction.Arn
        cluster_name:
          Ref: EKSClusterName
  MyIAMRole:
      Type: AWS::IAM::Role
      DependsOn: ClusterName
      Properties:
        AssumeRolePolicyDocument: !Sub |
          {
            "Version": "2012-10-17",
            "Statement": [
              {
                "Effect": "Allow",
                "Principal": {
                  "Federated": "arn:aws:iam::${AWS::AccountId}:oidc-provider/${ClusterName.oidc}"
                },
                "Action": "sts:AssumeRoleWithWebIdentity",
                "Condition": {
                  "StringEquals": {
                    "${ClusterName.oidc}:aud": "system:serviceaccount:default:my-serviceaccount"
                  }
                }
              }
            ]
          }
  LambdaIAMRole:
    Type: 'AWS::IAM::Role'
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - lambda.amazonaws.com
            Action:
              - 'sts:AssumeRole'
      Path: /
      Policies:
        - PolicyName: root
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              - Effect: Allow
                Action:
                  - 'eks:DescribeCluster'
                Resource: '*'
              - Effect: Allow
                Action:
                  - 'logs:CreateLogGroup'
                  - 'logs:CreateLogStream'
                  - 'logs:PutLogEvents'
                Resource: 'arn:aws:logs:*:*:*'
  LambdaFunction:
    Type: AWS::Lambda::Function
    Properties:
      Code:
        ZipFile: |
          import cfnresponse
          import boto3
          import json
          def lambda_handler(event, context):
              print("Received event: " + json.dumps(event, indent=2))
              oidc_response = ''
              responseData = {}
              try:
                  if event['RequestType'] == 'Delete':
                      print("Request Type:",event['RequestType'])
                      print("Delete Request - No Physical resources to delete")
                  elif event['RequestType'] == 'Create' or event['RequestType'] == 'Update':
                      print("Request Type:",event['RequestType'])
                      cluster_name = event['ResourceProperties']['cluster_name']
                      oidc_response_url = fetchClusterOIDC(cluster_name)
                      oidc_response=oidc_response_url.split("https://")[1]
                      responseData['oidc'] = oidc_response
                  print("Sending response to custom resource for event type " + event['RequestType'])
                  cfnresponse.send(event, context, cfnresponse.SUCCESS, responseData, "CustomResourcePhysicalID")
                  return oidc_response
              except Exception as e:
                  print('Failed to process:', e)
                  responseStatus = 'FAILURE'
                  responseData = {'Failure': 'Something bad happened.'}
                  cfnresponse.send(event, context, cfnresponse.FAILED, responseData, "CustomResourcePhysicalID")
          def fetchClusterOIDC(cluster_name):
              print("Getting Cluster OIDC value for cluster name "+ cluster_name)
              oidc = ''
              client = boto3.client('eks')
              try:
                  response = client.describe_cluster(
                      name=cluster_name
                  )
                  if response['ResponseMetadata']['HTTPStatusCode'] == 200:
                      print("Success response recieved for describing cluster "+ cluster_name)
                      oidc = (response['cluster']['identity']['oidc']['issuer'])
                      print('OIDC output recieved '+ oidc + ' for Cluster Name ' + cluster_name)
                  return oidc
              except Exception as e:
                  print('Failed to fetch Cluster OIDC value for cluster name ' + cluster_name, e)
      Handler: index.lambda_handler
      MemorySize: 1024
      Role: !GetAtt LambdaIAMRole.Arn
      Runtime: python3.7
      Timeout: 300
Outputs:
  OIDC:
    Description: EKS Cluster OIDC Value
    Value:
      Fn::GetAtt:
      - ClusterName
      - oidc

aws cloudformation create-stack --stack-name lambda-eks-oidc --template-body file://CustomLambdaEksOidc.template --parameters ParameterKey=EKSClusterName,ParameterValue=demo-newsblog --capabilities CAPABILITY_NAMED_IAM --region us-east-1