Feature request: `captureMethod` decorator for sync/async methods

[kennethwkz-mm]

Use case

Important

EDIT: see this comment for updated scope & context

For captureMethod - Method decorator able to support both async/sync function together

Solution/User Experience

We can add new option parameter - async to let user determine when the function need capture sync function.

class Something {
  tracer.captureMethod({ async: false })
  public myMethod {
     // do stuff
  }
}

Alternative solutions

const tracer = new Tracer();

const myFunction = () => { //do something  };

const handler = () => {
  const result = tracer.provider.captureFunc('my subsegment name', myFunction);
}

Acknowledgment

• This feature request meets Lambda Powertools Tenets
• Should this be considered in other Lambda Powertools languages? i.e. Python, Java

[dreamorosi]

Thank you for the feature request.

As discussed on Discord, I think the feature has merit. At the moment the decorator always assumes that the decorated method is async and as such it always returns a Promise and uses AWSXRay.captureAsyncFunc under the hood.

For most cases this is reasonable and/or harmless as it can be awaited by the caller, however I acknowledge that there are other cases in which this is not desirable.

One option to fix this would be the introduction of a parameter where the user specifies whether the decorated function is async or not (like the example in your post).

Another option, that should be investigated, would be to see if there's any way in which the decorator is able to automatically determine whether the method its decorating is sync or async, and based on that adjust its behavior and return type.

[github-actions]

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