Hi guys! I have a question regarding outputs. Let's say I need to create a resource B (step function), which takes a stringified json configuration. This config is stored inside a file. However, this configuration is templated, and relies on an arn of a previously created resource (resource A)

{

"Comment": "Save Restriction - Trigger Deletion - Restore on Fail",

"StartAt": "ExportRestrictionData",

"States": {

"ExportRestrictionData": {

"Type": "Task",

"Resource": "${resource_A_ARN}"

}

}

}

The problem is, that reading this file and replacing this variable won't work using language native functions, as it's an Output type at the time. I know you can circumvent the issue by creating resource B inside the

.apply()

block, but is there a better way without a potential callback hell? I was thinking about

pulumi.interpolate

I have basically the same challenge and I've tried so many different ways to get around it and I haven't had any luck yet

I sorta figured out the way. I just extended

String

type with the required function (

replacePulumi

accepting Output as a replacement value) The issue with this approach is that it only works once, as the return type is Output, so you can't chain

.repalcePulumi()

And you can't extend Output, as it doesn't have a prototype (I'm using type script) Unless there's a way?

@limited-rainbow-51650 any ideas?

In your language host, you will never be able to fetch the value from an

Output

directly. You will have to pass a callback function to

apply

. This is the inherent to the asynchronous nature of Pulumi where the program in your language host, and the provisioning by Pulumi run in different processes, communicating with each other via a local gRPC connection.

I understand that, that's why the

.replace.Pulumi

extension is nothing more than a wrap around .

replace

inside

.apply()

callback returning output. Would it be possible to extend the Output class to add additional functions? With casting later on. From what I see, .d.ts defines it as an interface rather than a class. Is there a reason for this?

pulumi.interpolate

and

pulumi.concat

are not enough for more complex string manipulations. For example, chained

.replace()