호스트 애플리케이션과 원격 애플리케이션

In Module Federation, applications play distinct roles: some are hosts, and others are remotes. Think of it like a main stage (host) that invites guest performers (remotes) to share their acts.

This setup allows large applications to be broken down into smaller, independently developed and deployed pieces.

The Host application is the primary application that boots up first. Its main job is to consume (or load) modules that are exposed by other applications, called Remotes.

It's like the main website that pulls in different widgets or sections from other services.

The Host application has a few crucial responsibilities:

• Loading Remotes: It tells Webpack which remote applications it needs to load.
• Providing Context: It often provides the overall application shell, routing, and shared dependencies.
• Integrating Modules: It renders components or uses functions provided by the remote applications.

A Remote application is a separate, self-contained application that exposes specific parts of its code for others to consume. It can also consume modules from other remotes (or even act as a host itself!).

These exposed parts could be components, utility functions, or even entire pages.

The Remote application focuses on:

• Developing Features: It builds specific features or UI components independently.
• Exposing Modules: It explicitly defines which parts of its codebase can be shared with host applications.
• Independent Deployment: It can be built and deployed without affecting the host or other remotes, as long as its exposed interfaces remain consistent.

Webpack's ModuleFederationPlugin is the magic behind this interaction. Both host and remote applications use this plugin in their Webpack configurations.

It orchestrates how modules are exposed by remotes and consumed by hosts, making them available at runtime.

On the Remote side, you use the exposes property in the ModuleFederationPlugin configuration.

This tells Webpack which files or modules from your remote application should be made available to others.

On the Host side, you use the remotes property to declare which remote applications you want to consume from.

You specify a unique name for the remote and its entry point URL.

When the Host application loads, it fetches the remoteEntry.js file from the configured remote URL. This entry file contains a manifest of all modules the remote exposes.

The Host can then dynamically import and use these exposed modules as if they were part of its own codebase.

Which of the following best describes the primary role of a Host application in a Module Federation setup?

We've learned about the fundamental roles of Host and Remote applications in Module Federation.

• Host apps are the main integrators, consuming functionality.
• Remote apps are independent units that expose specific modules.

Understanding these roles is key to building scalable micro frontends. Next, we'll dive deeper into setting up your first federated application!