How to wrap a Handler into another one

[nmoutschen]

Hey folks!

I'm doing a proof-of-concept of wrapping a lambda_runtime::Handler into another one. The idea is that I could then add and chain capabilities with a nice interface.

However, I'm facing an issue in how I call the actual function, since the Handler trait has a synchronous function call() that returns a Future. That means that I cannot await the function's call and then do something with the result. How could I handle that?

Here's the POC I currently have, with the problem highlighted: https://gist.github.com/nmoutschen/5a264d1d2d246d265517962ff91cba8c#file-wrap_handler-rs-L33

If I wrap the call into an async {} block, I then get the following error:

mismatched types
expected type parameter `Fut`
      found opaque type `impl Future`

[Mdrbhatti]

@nmoutschen you might find the following example helpful.
https://github.com/Mdrbhatti/warp_lambda/blob/main/src/lib.rs#L121

[nmoutschen]

Thanks a lot @Mdrbhatti ! It's working now! 😄

If anyone is interested, here's the code for reference: https://gist.github.com/nmoutschen/5a264d1d2d246d265517962ff91cba8c