feat(lambda-python): support build args (#12949)

[rirze]

Add support for passing build arguments when building the bundling
image.

Closes #12949

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

[gitpod-io]

[rirze]

If possible, I'd like some help in adding support for passing in Docker environment variables for both PythonFunction and PythonLayerVersion. I tried taking a look at how it was implemented in lambda-nodejs but my Typescript comprehension wasn't strong enough to port over that functionality to this module.

[eladb]

Did you consider exposing a bundling option (like in NodeJsFunction) which already allows specifying buildArgs.

[eladb]

Suggested change

	Use the `build_args` parameter to pass build arguments when building the bundling image:
	Use the `buildArgs` parameter to pass build arguments when building the bundling image:

[eladb]

Stylistic:

Suggested change

	readonly buildArgs?: { [key:string] : string };
	readonly buildArgs?: { [key:string]: string };

[rirze]

I did consider creating a bundling options class, but after looking at its implementation in aws-lambda-nodejs/bundling.ts, I couldn't separate what was essential to Docker and what was specific to Typescript bundling (esbuild).

If desired, I could try my hand at exposing a Bundling class for this module and we could iteratively refine it. I'd imagine this would require a few rounds of feedback.

Pull request has been modified.

[eladb]

@rirze there is already a BundlingOptions struct, why not reuse that? (like NodeJsFunction does)

@jogold any chance you can work with @rirze to align those APIs?

[rirze]

Hmm, I think I was confused because I assumed PythonFunction would need its own Bundling class like it does in NodeJsFunction (Bundling implements cdk.BundlingOptions). But looking it more, it seems like most of the logic there is related to esbuild. So making sure I understand correctly, passing in a cdk.BundlingOptions should be sufficient for PythonFunction/PythonLayerVersion, correct?

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[jogold]

We currently have the following API for the NodejsFunction:

• a bundling prop in NodejsFunctionProps of type BundlingOptions:

  aws-cdk/packages/@aws-cdk/aws-lambda-nodejs/lib/function.ts

  Lines 69 to 75 in 2691986

  	/**
  	* Bundling options
  	*
  	* @default - use default bundling options: no minify, no sourcemap, all
  	* modules are bundled.
  	*/
  	readonly bundling?: BundlingOptions;

• in there we have buildArgs:

  aws-cdk/packages/@aws-cdk/aws-lambda-nodejs/lib/types.ts

  Lines 175 to 180 in 2691986

  	/**
  	* Build arguments to pass when building the bundling image.
  	*
  	* @default - no build arguments are passed
  	*/
  	readonly buildArgs?: { [key:string] : string };

I think we can do the same here.

[eladb]

@rirze I am closing this PR for now. Feel free to re-open when ready to continue :-)