Long strings/refs incorrectly split over newlines causing broken user-data/etc

When I am building strings to use in my user-data/etc, CDK seems to incorrectly insert newlines (at long lines?), causing scripts to break.

Relevant Snippets from code:

const cfnInitCmd = `/opt/aws/bin/cfn-init -v --stack=${new cdk.AwsStackName} --region=${new cdk.AwsRegion} --resource=${asgLaunchConfig.logicalId}`;

appAsg.addUserData(
            "yum install -y aws-cfn-bootstrap;",
            `${cfnInitCmd} --configsets install;`,
            `/opt/aws/bin/cfn-signal --stack=${new cdk.AwsStackName} --region=${new cdk.AwsRegion} --resource=${asgLaunchConfig.logicalId} --exit-code \$?;`,
        );

When synthesized, this ends up like:

AppAutoScalingGroupLaunchConfig48178128:
    Type: AWS::AutoScaling::LaunchConfiguration
    Properties:
..snip..
      UserData:
        Fn::Base64:
          Fn::Join:
            - ""
            - - |-
                #!/bin/bash
                yum install -y aws-cfn-bootstrap;
                /opt/aws/bin/cfn-init -v --stack=
              - Ref: AWS::StackName
              - " --region="
              - Ref: AWS::Region
              - >-2
                 --resource=AppAutoScalingGroupLaunchConfig48178128 --configsets
                install;
                /opt/aws/bin/cfn-signal --stack=
              - Ref: AWS::StackName
              - " --region="
              - Ref: AWS::Region
              - " --resource=AppAutoScalingGroupLaunchConfig48178128 --exit-code
                $?;"

Which ends up in the end user-data as:

#!/bin/bash
yum install -y aws-cfn-bootstrap;
/opt/aws/bin/cfn-init -v --stack=TokenizedEC2 --region=ap-southeast-2 --resource=AppAutoScalingGroupLaunchConfig48178128 --configsets
install; /opt/aws/bin/cfn-signal --stack=TokenizedEC2 --region=ap-southeast-2 --resource=AppAutoScalingGroupLaunchConfig48178128 --exit-code $?;

Note how the install parameter ends up on a new line, when it shouldn’t, which then breaks things.

This is also happening in my AWS::CloudFormation::Init Metadata override, breaking my /etc/cfn/cfn-hup.conf config.

[eemeli]

This should be fixed by the just-released version 1.1.0 of yaml. It’s also now clearer how to disable line folding altogether.

[eladb]

If we allow users to synthesize YAML, then it should work. It would be an awful experience if “cdk deploy” worked and “cdk synth” didn’t. Happy to continue to try make YAML work, but I am concerned…