[Feature]: Build orchestration API

[jacob-ebey]

What problem does this feature solve?

In some situations (such as RSC) we need to be able to orchestrate the order and number of times an environments build is ran. A simple example of this goes something like this:

1. Build server, discover "use client"
2. Build client with discovered client modules, discover "use server"
3. Re-build server with discovered server modules, discover new "use client"
4. etc...

What does the proposed API look like?

Vite's new environments API comes with a builder.buildApp API and I propose something very similar for use here:

export default defineConfig({
  builder: {
    buildApp: async (builder) => {
      await builder.build(builder.environments.browser);
      await builder.build(builder.environments.server);
    },
  },
});

This would allow us to write logic such as:

export default defineConfig({
  builder: {
    buildApp: async (builder) => {
      do {
        checkpointDiscoveredModules();
        await builder.build(builder.environments.server);
        await Promise.all([
          builder.build(builder.environments.browser),
          builder.build(builder.environments.ssr),
        ]);
      } while (discoveredNewModules());
    },
  },
});

[chenjiahan]

I totally agree, Rsbuild needs to provide similar capabilities.

First we need to clarify what is the main difference between the proposed builder.build API and Rsbuild's JavaScript API (rsbuild.build()). And I wonder if it should be implemented via the JavaScript API rather than the Rsbuild configuration.

[jacob-ebey]

I'm beyond tired of having to maintain "build CLIs". Vite's approach is correct here. It allows a plugin / framework to define the order / interplay between builds completely within their plugin. No more xyz build, xyz dev. It's just bundler dev builder build --app to specify we want the output of the environments that make up the cohesive application. For cohesion today everywhere except for Vite6 MUST be done via a custom maintained CLI / tool that uses the specific bundler JS APIs.

[jacob-ebey]

I'd recommend implementing it via the JS API and exposing that to plugins / config via the above convenience layer so it can be used "internally" instead of "externally".

[chenjiahan]

Ok, so our goal is to allow Rsbuild plugin to orchestrate the build process, instead of calling JS API via a custom CLI. This should be useful for frameworks like Remix.

We will look at the design of Vite 6 next week and consider how Rsbuild can achieve this.