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that's the (rough) desired end state - but I'm not sure how to get there from the callbackfactory:

callbackFactory

creates a callback function, it is used to build the global state of the function during cold starts like initializing clients that will reuse resources. The type system should have an error there for returning true instead of a

Callback<E, R>

@green-school-95910 got it. so callbackfactory is for cases where I want to run logic at "pulumi up" time to initialize something prior to the deployment? What would be the approach to get the output I pasted in the first screenshot?

No it is logic run on the lambda, but not for every request, just to initialize global values, like instantiating a grpc client or a s3 client:

new aws.lambda.CallbackFunction("foo", {
  callbackFactory: () => {
    const s3 = new AWS.S3();
    return async (event) => {
      // ... save event details on S3 ...
    };
  },
);

trying that out. Thanks Luiz

If it is an

Output

from somewhere else you don't need the factory:

// Defined from other resources somewhere
const accessMeFromTheCallback: Output<string>

new aws.lambda.CallbackFunction("foo", {
  callback: async (event) => {
    // .get() is required here to extract the string
    // from the `Output` instance
    console.log(accessMeFromTheCallback.get());
  };
);

If you just need it to be global on the function you use the same as I did for

s3

on the example above of

callbackFactory

I think that worked! 👍 thanks Luiz! Related question - a bunch of lambda SaaS services work by wrapping the handler function (like Rookout):

You can do that on the factory

new aws.lambda.CallbackFunction("foo", {
  callbackFactory: () => rookout.wrap(async (event) => {
    // ...
  });
);

perfect! Thanks a whole bunch @green-school-95910! Much appreciated!

You are welcome! 🙂

just popping in to say hi, @chilly-magazine-6129. we worked together at MSFT. 🙂

👋 hey Alex! 😄 small world. ❤️