Feature request: Plans for alternative parser implementations

[WtfJoke]

Use case

We currently heavily use zod in our projects. The new Parser (Zod) utility could help us (since we validated most of them manually).
Since we have use a lot of single purpose lambdas, we try to keep our lambda bundle size low. We noticed that zod takes a good part of that, because their api (as great as it is :D) its not well suited for tree shakability (see colinhacks/zod#2596). We made some experiments in the past with alternatives like valibot.

While I can understand why you choose zod (I would have too, in your situation :D), are there any plans to support other Schema Validation Libraries like valibot in this case? Im curious about your plans :)
It feels like the Parser Utility could support multiple schema libraries like the Parameters Utility supports Secrets-Manager and Parameter Sotre.

I am aware of, that you care about bundle size as well, so it seems like a good fit :)
I'm also aware that valibot hasnt reached 1.0 and has most likely a breaking api change (see fabian-hiller/valibot#502)

P.S: If you think that idea is better suited in a discussion, I can close this issue.

Solution/User Experience

I just adapted the example of the readme (it probably doesn't compile, just to get the idea)

import type { Context } from 'aws-lambda';
import { isoTimestamp, object, parse, string, type Output } from "valibot";
import middy from '@middy/core';

const TimestampSchema = object({
  timestamp: string([isoTimestamp()]),
});

type Timestamp = Output<typeof TimestampSchema>;

const lambdaHandler = async (
  event: Timestamp,
  _context: Context
): Promise<void> => {
    console.log('Processing event', {event});
};

export const handler = middy(lambdaHandler).use(
  parser({ schema: TimestampSchema })
);

Alternative solutions

Alternative parsers:
- https://github.com/hapijs/joi
- https://github.com/ajv-validator/ajv

Acknowledgment

• This feature request meets Powertools for AWS Lambda (TypeScript) Tenets
• Should this be considered in other Powertools for AWS Lambda languages? i.e. Python, Java, and .NET

Future readers

Please react with 👍 and your use case to help us understand customer demand.

[boring-cyborg]

Thanks for opening your first issue here! We'll come back to you as soon as we can.
In the meantime, check out the #typescript channel on our Powertools for AWS Lambda Discord: Invite link

[dreamorosi]

Hi @WtfJoke thank you for taking the time to open an issue and for bringing up this topic.

We have considered the idea during development and like you said, the utility lends itself to a model where you could switch the underlying library. However to be frugal with time and pragmatic with efforts, we decided to go with Zod first.

For this first version we settled on Zod mainly because we thought it'd help a wider audience both as a reflection of its larger user base (8.7M downloads/week vs 142K downloads/week for valibot) and the time/effort investment that customers might have already put in creating schemas for it.

As secondary factors, we also took in account the fact that - like you mentioned - valibot is still not stable, and other AWS projects like Amplify have also adopted Zod.

Overall I think that if valibot becomes stable and Powertools customers ask for it, we could consider adding this capability in a future major version. Since we maintain a collection of schemas and envelopes for AWS events, this would require us doubling the maintenance for each provider we add, however as long as the Parser utility gains traction and there's significant customer demand, I don't think it's out of question.

I think we should leave the issue open so that people can express their interest.

[WtfJoke]

Thanks for the insights! Totally understandable

[dreamorosi]

As a side note, that doesn't in any way invalidate the ask, I also wanted to surface that Zod appears to be working on a v4 that should improve with tree shaking & bundle size. We are keeping an eye on the development and will consider adopting once it's out.

[fabian-hiller]

I am the creator of Valibot and happy to help and answer questions if you consider supporting Valibot. I expect to release a stable version within the next 2 or 3 months.

[dreamorosi]

Circling back to this after a few months to provide an update.

The utility went GA (Generally Available) in the last release and has seen decent usage so far. Our position on this topic hasn't changed and we are still open to consider alternative libraries provided there's demand and a stable alternative.

We'll revisit this again in ~3 months to see if either has changed. In the meantime perhaps the Parser utility will have gained additional usage.