Hi there! I'm trying to setup a new pulumi project using typescript and, from the docs, I gather that exporting an async function that returns the desired output should be sufficient. However, running that pulumi program has no effect. If I export the promise resulting from calling that function, it does work. Are the docs wrong or am I missing something?

I just tried this with a new

aws-typescript

project (based on the doc you linked), and it seems to work for me:

import * as pulumi from "@pulumi/pulumi";
import * as aws from "@pulumi/aws";

export = async () => {
    const bucket = new aws.s3.Bucket("my-bucket");

    return {
        bucketName: bucket.id,
    };
}

Output:

➜ pulumi up
Previewing update (dev)

     Type                 Name                        Plan       
 +   pulumi:pulumi:Stack  aws-typescript-cfe895a-dev  create     
 +   └─ aws:s3:Bucket     my-bucket                   create     

Outputs:
    bucketName: output<string>

Resources:
    + 2 to create

Does your code look different?

Interesting! The only difference is that I have

export default

instead. I'm not familiar with the

export =

syntax.

More or less, yeah.

export =

is a TypeScript thing for use with CommonJS. It's essentially like saying

module.exports = { your: stuff }

(and indeed compiles to that in JS). https://www.typescriptlang.org/docs/handbook/modules/reference.html#export--and-import--require

Ah, perfect. So this is indeed a type of export that is impossible with ESM, hence the warning. I guess there's something in my tsconfig tricking tsserver into thinking it's targeting esm. I'll look into that. Thanks for the clarification, that taught me something new!

You bet! Thanks for asking and glad that helped. Check your

tsconfig.json

and make sure it's not

"type": "module"

-- that could be it.

Btw, after changing the code to use

export =

, I noticed the following message when a stack update fails:

error: update failed

    The Pulumi runtime detected that 171 promises were still active
    at the time that the process exited. There are a few ways that this can occur:
      * Not using `await` or `.then` on a Promise returned from a Pulumi API
      * Introducing a cyclic dependency between two Pulumi Resources
      * A bug in the Pulumi Runtime
    Leaving promises active is probably not what you want. If you are unsure about
    why you are seeing this message, re-run your program with the `PULUMI_DEBUG_PROMISE_LEAKS`
    environment variable. The Pulumi runtime will then print out additional
    debug information about the leaked promises.

I wonder if this is due to the fact I'm exporting an async function or maybe it has to do with the usage of promises as inputs to other resources.