cdk.Include: support passing in parameters to included template

[eladb]

Users expect to be able to pass in parameters to the included template

[arvindshekar07]

I too have a similar issue specially when attempting a blue green deployment.

[jeshan]

I found a simple workaround:

from cfn_tools import load_yaml # or load_json
template = load_yaml(open('templates/your-template.yaml').read())

From there, you can manipulate the template as you please, e.g set the default value to the desired value:

template['Parameters']['YourParam']['Default'] = 'YourValue'

It leverages AWS's cfn-flip library: pip install cfn_flip. The example is in Python but note that this is a CLI tool as well if you need it for other languages.

[ilepadatu-pentalog]

We need this feature. The problem inherent with Default is that in Cloud Formation the value of the Default field cannot reference the output of another template.
That is, if I want to pass to a cfn template parameter the output of of another template, I am unable to, due to CloudFormation limitations.
The work-around is to modify the template, that is remove all the parameters declarations that should accept references and replace the statements where they are assigned with the references from another stack by loading the template into a variable, pretty much as @jeshan described (I used json instead). But the template will never work as it was edited...
I find this very useful in case one wants to embed already existing cfn templates in their cdk code and leave the templates clean to have a way of passing outputs from cdk stack as input parameters to an already existing template without modifying it.

[skinny85]

This is now possible with the new cfn-include module.

Resolving, please let us know if there's anything else we can do for this issue.