Bug: unable to build with `tsc` when not using `@middy/core`

[rreddypally]

Bug description

EDIT: see this comment for updated info after triage.

---

The import statement in Tracer.ts for TracerInterface is importing all the modules from the root. https://github.com/awslabs/aws-lambda-powertools-typescript/blob/main/packages/tracer/src/Tracer.ts#L3.

I am trying to use tracer module without the need to install middy.

Expected Behavior

Should be able to use Tracer without the need to import middy when its not used.

Current Behavior

This behavior is forcing to import middy middleware

Possible Solution

import { TracerInterface } from './TracerInterface';

Steps to Reproduce

1. Install tracer npm module npm i @aws-lambda-powertools/tracer
2. Import tracer import { Tracer } from "@aws-lambda-powertools/tracer/lib/Tracer";
3. Add tracer annotation and build fails with error TS2307: Cannot find module '@middy/core' or its corresponding type declarations.

Environment

• Powertools version used: 1.1.1
• Packaging format (Layers, npm): npm
• AWS Lambda function runtime: Node 16

[dreamorosi]

Hi @rreddypally thank you for opening this issue.

I have tried reproducing the issue you describe but unfortunately I am not able to.

In the docs we recommend to import the Tracer directly (i.e. import { Tracer } from '@aws-lambda-powertools/tracer';), however even if I import it like you suggest I am still able to bundle the function, run it successfully on AWS Lambda, and see the annotated segment in the traces.

I have made a screen record in which I create a new project from zero and I set up the latest version of Tracer in a function, then bundle it, and then deploy & run it. As mentioned, I have tested both import statements (the recommended one, and the scoped one), and both build & run successfully.

As you'll see in the video, I never install Middy and I only install esbuild to bundle, and @types/node for types (probably redundant anyway).

2022-08-22.14-03-14.mp4

Additionally, as a side note, you'll see that the file containing the LambdaInterface never imports Middy, and the same applies to the types file which is the only other imported file. The only Middy-related import is in the middleware file, which should be imported only if you import the captureLambdaHandler middleware, which requires Middy.

Please let me know if this answers your question.

[rreddypally]

EDIT from maintainer: removed zip archive

Hi @dreamorosi, thanks for taking time and record the extensive demo.

I have attached a typescript demo which fails to compile without middy.

Steps:

1. Unpack the demo
2. Run npm run build which uses tsc to compile
3. Get this error. "node_modules/@aws-lambda-powertools/tracer/lib/middleware/middy.d.ts:1:24 - error TS2307: Cannot find module '@middy/core' or its corresponding type declarations."

I think esbuild would have the smarts to eliminate the unused modules while tree shaking which is the reason why your demo works.

Hope this helps.

[dreamorosi]

Unfortunately I'm not allowed to download archives from public websites on my machine.

Could you please provide a sample repo here on GitHub with its content so I can take a look? Thanks for your understanding

[rreddypally]

No problem at all.

Here is the repo: https://github.com/rreddypally/tracer-demo

Let me know if you have trouble accessing it.

[dreamorosi]

Thank you for providing the repo.

I can confirm that I am able to reproduce the issue you describe, which happens only when bundling with tsc instead of esbuild.

I was also able to confirm that the issue affects the Logger & Metrics utilities as well.

We're going to need a bit more time to investigate this though, the fix that you suggested in the PR #1069 does not seem to fix the issue for me, at least when using the standard import { Tracer } from "@aws-lambda-powertools/tracer" import (it does fix it when importing @aws-lambda-powertools/tracer/lib/Tracer but I'd like to see what are our options.

I'm going to rename the issue, after that would you be so kind to please open two more issues one for Metrics & another for Logger with the same title? Would really appreciate and also would like to reflect that you actually discovered the issue.

[dreamorosi]

@rreddypally: In the meanwhile, if you don't want to use esbuild, you can add @middy/core as a dev dependency to your project (npm i -D @middy/core) and the build will succeed. I have verified that there's no trace of Middy in the built output so it won't have any effect on your end result.

I know it's not ideal but it's a temporary solution while we find a better one.