[Extension Proposal] AsyncAPI generator

[rquinio1A]

Description

Interested in this extension, please +1 via the emoji/reaction feature of GitHub (top right).

The go-to library to generare Java model classes from an AsyncAPI document is modelina
However, as it's a typscript library, using it in a Maven project requires a lot of boilerplate (frontend-maven-plugin + npm package.json + generator.ts).

There are probably 2 questions to answer for such an extension:

1. Where to host the extension ?

• As a sub-module of quarkus-openapi-generator (cf #Extend Support for code generation of Async Api quarkiverse/quarkus-openapi-generator#617) ? It could probably share a lot of configs and templates for JSON schema -> Java POJO generation.
• As a module of quarkus-asyncapi (cf Contract-first extension scope quarkiverse/quarkus-asyncapi#138) ?
• As a standalone extension ?

2. Which Java generator to use ?

• https://github.com/OpenAPITools/openapi-generator has the most advanced capabilities, but only works on OpenAPI documents. It's however possible to take the components section of an AsyncAPI and create an intermediate OpenAPI document with that.
• https://github.com/Apicurio/apicurio-codegen doesn't support AsyncAPI v3

I have a PoC that generates an intermediate OpenAPI document and calls quarkus-openapi-generator on it, but it brings "quarkus-rest-client" dependencies, which don't make sense for event-driven microservices.

Ideally I'd want the same capibilities and user experience for schema-first developement with Quarkus, whether it is for REST server, REST client or event processors.

/cc @hbelmiro @ChMThiel @fjtirado

Repository name

quarkus-asyncapi-generator

Short description

Generate Java POJO from AsyncAPI components

Repository Homepage URL

https://quarkiverse.github.io/quarkiverse-docs/quarkus-asyncapi-generator/dev/

Repository Topics

No response

Team Members

No response

Additional context

No response

[quarkus-bot]

/cc @aloubyansky (extension-proposal), @gastaldi (extension-proposal), @gsmet (extension-proposal), @maxandersen (extension-proposal)

[ChMThiel]

I think that's a question mainly for @fjtirado since it's for the contract-first part of the extension...

[maxandersen]

on first hunch this feels like a thing the asyncapi extension could/should do - but I honestly know too little about asyncapi to say which generator to use.

[maxandersen]

completely out-of-box thinking...would a modelina extension make sense?

one that allows generation using modelina?

similar to how done for kiota?

[maxandersen]

btw. modelina does not seem to implement/generate a client just generate the model do I read that right?

[rquinio1A]

btw. modelina does not seem to implement/generate a client just generate the model do I read that right?

Indeed it generates only the payload model class, in v3 it's components.schemas.* referenced from components.messages.[eventName].payload.$ref.
I've seen requests to also generate wrappers for components.messages.[eventName] containing event metadata (cloud events, headers, ...), but smallrye-reactive-message has its own APIs to manipulate such metadata so I think it doesn't matter.

completely out-of-box thinking...would a modelina extension make sense?
one that allows generation using modelina?
similar to how done for kiota?

Here's an example of calling it from a Maven project: https://github.com/asyncapi/modelina/tree/master/examples/integrate-with-maven
Do you mean Quarkus could hide this boilerplate by packaging nodejs + npm pre-requisites into an extension ?

[maxandersen]

Do you mean Quarkus could hide this boilerplate by packaging nodejs + npm pre-requisites into an extension ?

kinda - we have quinoa that does that for webapp usage and webbundler that bundles esbuild to enable interesting usecases.

not sure if it suffices for modelina - personally I'm not a fan of dragging nodejs ecosystem in just to generate some classes - but if that's what is available ...

[andreaTP]

Hi @rquinio1A !
It's pretty straightforward to hide some setup in a Quarkus Extension, and you have various alternatives, in quarkus-kiota we are wrapping a CLI.

In no particular order, things that can work:

• create a Node CLI (there are a few independent projects and this more official) and wrap it
• try to execute modelina on a Java JS runtime like Nashorn
• embed the full node distribution

[andreaTP]

I quickly hacked around a POC: https://github.com/andreaTP/quarkus-modelina-poc

You can check the basic usage in the integration-tests.

It uses eirslett/frontend-maven-plugin behind the scenes to setup Node, NPM and install Modelina etc.

Not sure if there is any better recommendation on how to implement this kind of automation cc. @ia3andy

[radcortez]

We did some prototype work for AsyncAPI in SmallRye: https://github.com/smallrye/smallrye-async-api