Lifting

Besom supports a feature called lifting which allows the user to access properties of data structures held by an Output as if the value was not inside the asynchronous datatype. Let's look at our handy S3 bucket again:

import besom.*
import besom.api.aws

@main def main = Pulumi.run {
  val s3Bucket: Output[aws.s3.Bucket] = aws.s3.Bucket("my-bucket")

  Stack.exports(s3Url = s3Bucket.map(_.websiteEndpoint))
}

As you can see here we're accessing the property websiteEndpoint on aws.s3.Bucket class by first mapping over the Output. This syntax can be replaced in Besom thanks to first class support of lifting via Scala 3 extension methods generated in packages for Besom:

extension (o: Output[aws.s3.Bucket])
  def websiteEndpoint: Output[String] = o.map(_.websiteEndpoint) 

This allows for this syntax:

Stack.exports(s3Url = s3Bucket.websiteEndpoint)

These lifted syntaxes cover more cases and work recursively, so you can access even the properties on nested data structures like a.b.c.d with a direct syntax.