[FEATURE] Add custom folder path option for Smithy-generated handlers

[fahadnasir40]

Describe the feature

Add an option in the Smithy handler trait to define a custom folder path for the generated handers.

Use Case

Current settings generate all handlers inside the src and test folders with a flat hierarchy. Need an option to customize the individual handler path.

Proposed Solution

Add a new optional subdir option to the Smithy handler trait?

Other Information

We may also need to add this option for async handlers.

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

PDK version used

0.23.66

What languages will this feature affect?

Typescript, Java, Python

Environment details (OS name and version, etc.)

Linux, Windows etc

[cogwirrel]

I think the tricky part for typescript will be getting the esbuild command right to bundle all the handlers - I wonder if we'd need to make it more generic so it finds all ts files in the target directory which export a function called handler? :) Not sure exactly the best way to achieve this though - could maybe add a new script to run.ts but it might increase the size of the bundled run.js that ends up in the PDK distributable as that itself would then include esbuild!

[fahadnasir40]

I think we may need an index file to store the paths of the generated handlers. Is it possible to read handler data from the model/.api.json file? I'm not quite sure how these projects are linked together. If we choose to scan all files in src/**/* directory, we can run a command with a regex and pass the result to the current esbuild command.

[cogwirrel]

We can read the model/.api.json at build time (just not at project synthesis time as users should be able to add an operation and just rebuild rather than having to re-synthesize too).

So yes I think we could have a script/command read model/.api.json to find where all the handlers are and pass that to the esbuild command :) Ideally I think we'll want this as a node.js script which we can then pass the output to esbuild, so it's as platform agnostic as possible :)