Cloudformation ImportValue within ParameterOverride CodePipeline

Question

Problem: I have a cloudformation template that is supposed to retrieve code found in CodeCommit and push it to a Lambda. The code in CodeCommit also contains a SAM template with a few parameters. The SAM template has the following setup

AWSTemplateFormatVersion: 2010-09-09
Transform: AWS::Serverless-2016-10-31
Description: SAM Template for Deploy Python code to Lambda

Parameters:
  ArtifactsBucket:
    Description: The artifact bucket to get the lambda code
    Type: String
  Name:
    Description: Name of the lambda function
    Type: String
  SqsARN:
    Description: AWS SQS Arn to act as a trigger for the lambda function
    Type: String
...

and the CodePipeline Cloudformation template has the following to override the 3 parameters present in the SAM template.

...
 - Name: Deploy
    Actions:
    - Name: Deploy
      ActionTypeId:
        Category: Deploy
        Owner: AWS
        Provider: CloudFormation
        Version: 1
      Configuration:
        ActionMode: CREATE_UPDATE
        Capabilities: 'CAPABILITY_IAM,CAPABILITY_AUTO_EXPAND,CAPABILITY_NAMED_IAM'
        ChangeSetName: !Join 
          - '-'
          - - lambda
            - !Ref CodeCommitRepoName
        ParameterOverrides: !Sub |
          {
            "ArtifactsBucket": "${ArtifactsBucket}",
            "Name": "${CodeCommitRepoName}",
            "SqsARN": {"Fn::ImportValue": "My-queue:us-east-1:Queue:Arn"}
          }
...

The ArtifactBucket and the Name parameters are easily changed by the !Sub function but I am not able to have a valid value for SqsARN which is an imported value.

QuestionIs there anyway to include ImportValue in conjungtion with a Sub function within ParametersOverride?

Attempts I also tried to switch from

{"Fn::ImportValue": "My-queue:us-east-1:Queue:Arn"}

to

!ImportValue": "My-queue:us-east-1:Queue:Arn"

which also did not work. Remove the !Sub function and using a !Ref function yields the same output/problem as with ImportValue.

Answer 1

Key thing to remember is, using JSON within YAML

From the documentation

You can't use the short form of !ImportValue when it contains a !Sub. It is valid for AWS CloudFormation, but not valid for YAML:

Assuming Environment as Parameter, Here is a working example of Sub >> ImportValue >> Sub

        Value: !Sub
            - '{
              "sqsUrl": "${sqsUrl}",
              }'
            - {
                  sqsUrl: { 'Fn::ImportValue': { 'Fn::Sub': 'QueUrl-${Environment}' } }
              }

Applying it to above example might look something like below(using ssm for testing)

Parameters:
    Environment:
        Type: String
        Default: DV
    ArtifactsBucket:
        Type: String
        Default: TestBucket
    CodeCommitRepoName:
        Type: String
        Default: Test

Resources:
    SmsLambdaParameter:
        Type: 'AWS::SSM::Parameter'
        Properties:
            Name: !Sub
                - '/${EnvFullUpper}/My-Param/Test'
                - { EnvFullUpper: !Ref Environment }
            Type: 'String'
            Value: !Sub
                - '{
                  "ArtifactsBucket": "${ArtifactsBucket}",
                  "Name": "${CodeCommitRepoName}",
                  "SqsARN": "${SqsArn}"
                  }'
                - { SqsARN: { 'Fn::ImportValue': { 'Fn::Sub': 'QueueArn-${Environment}' } } }