I am really struggling with understanding how outputs work in Pulumi. Here's what I'm trying to do. After creating an alb loadbalancer with

new aws.alb.loadbalancer

I'm trying to use an output in a userdata script:

const test = "test"

const dnsName = lb.dnsName

const userData =

``#!/bin/bash`

echo Test string: ${test}

`echo ${dnsName}``

console.log(userData)

The diagnostic log produces:

#!/bin/bash

echo Test string: test

echo Calling [toString] on an [Output<T>] is not supported.

To get the value of an Output<T> as an Output<string> consider either:

`1: o.apply(v =>

prefix${v}suffix

)` `2: pulumi.interpolate `prefix${v}suffix``

See <https://pulumi.io/help/outputs> for more details.

This function may throw in a future version of @pulumi/pulumi.

I've been through the output documentation in the URL in addition to combing this Slack workspace but I can't seem to find a solution here. How can I use the dnsName output from the lb resource as a pure string?

As the note pinned to the channel mentions - the answer is basically always to use apply :-). In this case you can/should use both the suggestions: 1.

userData = pulumi.interpolate

...`` 2.

userData.apply(d => console.log(d))

The key is that because one of your inputs is an “output”, your user data will also need to be an “output”.

It finally clicked. I was so intent on being able to see the string from a log statement that I was attempting to use apply on the original output, not the variable I wanted the output to appear in. Thank you again for your help. Just for feedback, I think it would help a lot of new users if you included a functional example using cloud resources on the outputs help page.