Using Multiple Instances of Module Federation Plugin in single build and Cross-Bundler Compatibility: Is Official Support Available?

[sudhakar-selva]

We have an existing federated host (App A) that we want to use as a remote in another federated host (App B). However, the current remote entry of App A is not working in App B due to some issues. We managed to get it working by removing other remotes and only exposing the modules required by App B in App A's webpack configuration. Since other apps rely on App A, we're considering adding an additional instance of the Module Federation plugin in App A, resulting in two remote entries: x.remoteEntry.js and xyz.remoteEntry.js(Refer below config).

// webpack.config.js - App A
plugins: [ModuleFederationPlugin(config1), ModuleFederationPlugin(config2)]

We are trying to find the source of this issue and are considering this approach as a last resort.

One last thing, can we consume federated apps from different bundlers? i know this works but is it officially supported? If so, is it supported only for v2, or for both versions?

[ScriptedAlchemy]

In v1 it was. I think in v2 we place some restrictions on it due to how underlying plugins are applied.

A better approach would be to use ContainerPlugin and not the full MF plugin again. So MFPlugin + ContainerPlugin
Would that work?

Regarding cross bundler support. Consider v1 dead. Assume nothing works, but v2 can load v1 remotes. Cross bundler is supported by anyone who implements the v2 runtime. So webpack,rspack,vite plugins from us are all interoperable. Esbuild is too alpha to work with interop and we may not support esbuild due to how limited of an api it has.

You can also use the federation runtime package a vanilla- which works anywhere.

[sudhakar-selva]

Got it, I'll try the MFPlugin + ContainerPlugin combination. Thanks!🖖.

[ScriptedAlchemy]

Let me know if it works. This limitation is something I do want to look at resolving. But if container plugin works I'll update the docs with a strategy for users to follow

[sudhakar-selva]

Surething 👍

[sudhakar-selva]

Update: The V1 Container plugin worked without any issues!. I still need to try it with the V2 container plugin.

By the way, could you please help me understand more about this approach? It seems interesting, but I'd like to know its trade-offs and benefits. Thanks again!

[ScriptedAlchemy]

V1: You can use the MF plugin multiple times.
V2: We have some hooks that we only want to run once. So applying the MF plugin twice will cause our validation to fail.

In both cases, applying MF multiple times will cause the runtime modules to be applied multiple times. For example, the sharing system will be duplicated, etc. When in reality, what you want is just another container with some extra or different configs, not to duplicate the entirety of federation and its mechanisms several times.l