Cloudformation ImportValue within ParameterOverride CodePipeline - amazon-web-services

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}' } } }

Answer 2

You can use array form of Fn::Sub:
!Sub
- String
- Var1Name: Var1Value
Var2Name: Var2Value
which would result in:
ParameterOverrides: !Sub
- |
{
"ArtifactsBucket": "${ArtifactsBucket}",
"Name": "${CodeCommitRepoName}",
"SqsARN": "${SqsARNImport}"
}
- SqsARNImport: !ImportValue <name-of-your-queue-export>