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Hi all. Is there a way to call async functions inside pulumi code (Typescript) ? I often find it useful to execute other tasks (write a file, call an api, etc) based on resources created by pulumi. In another runtime this wouldn't be an issue - but many node packages are async only - and I have not been able to use them with pulumi. Anyone had success with this?

what problems are you having? i haven't had any issues calling async stuff

`Input&lt;T&gt;` includes `Promise&lt;T&gt;`. You should be able to just pass through the promise.

Yes - you can.  You are possibly struggling most with this at top level in your Node modules (or index.ts), where JavaScript does not directly support `async`/`await`.

You can work around this by putting your code inside `async function main() { ... }` and then invoking `main()` at top level.

Ha. Thanks. Good to know - I guess this top level trick was one of the missing pieces. I'll try again just knowing that it should work fine and see where I get stuck.

Thanks for the help <@UB3BGTV63> and others - I'm able to use async now :slightly_smiling_face:
One remaining question - I'm updating some external api based on a pulumi resource (e.g. in an `output.apply`), this is executed even on previews or when the resource hasn't changed.
I presume a better way to do this is to create a Custom Resource? Are there any examples of how to do that - or other recommended patterns?

there's a "dynamic provider" examples are in this repo:
<https://github.com/pulumi/pulumi/blob/master/examples/dynamic-provider/derived-inputs/index.ts>

i've had problems with it though - it serializes the source code into the stack and because it gets serialized differently on linux and windows it causes unnecessary changes for some of our team

ok great, thanks <@UEU2M37GX>. I'll take a look a look at that.