Server Plugin API

[hutchgrant]

Related Issue

Resolves #470

Summary of Changes

• Adds a new Server Plugin API similar to resource plugins, similar plugin definition
• Utilizes ServerInterface
• Plugins declared with type: "server"
• develop.js command plugin will call start() function from plugin when running greenwood in development mode
• livereload is used as an example of how to implement

THIS IS JUST A PROTOTYPE /POC

[thescientist13]

Nice, this is definitely a great start and is pretty much mostly complete from what i can see! (aside from needing some docs and considering the below feedback 👇 )

One thought here is that if we can extract the livereload <script> tag snippet out of our standard HTML plugin, we could completely encapsulate all the related functionality. 🎉

So the export could be something like this:

class LiveReloadServer extends ServerInterface {
  ...
}

class LiveReloadResource extends ResourceInterface {
  ...
}

module.exports = (options = {}) => {
  return [{
    type: 'server',
    name: 'plugin-live-reload-server',
    provider: (compilation) => new LiveReloadServer(compilation, options)
  }, { 
    type: 'resource',
    name: 'plugin-live-reload-resource',
    provider: (compilation) => new LiveReloadResource(compilation, options)
  }]
};

And greenwood.config.js would look something like this.

const pluginLiveReload = require('./packages/cli/src/plugins/server/plugin-livereload');

module.exports = {
  plugins: [
    ...pluginLiveReload({ /* options */ }) // notice the spread! ...
  ]
};

I'm sure it could get more elegant with some extra thought, but this definitely gets the job done for now and is pretty effective, IMO.

What I really like about being able to combine it all into one is that later on, I would like to introduce a HotModuleReplacement (HMR) plugin, and thus allow user's the option to choose which developer experience they would like, would be 👌

---

On a related note about extracting LiveReload from the CLI down the road, is that we will likely want to deprecate devServer from greenwood.config.js since likely each server plugin will have its own unique configuration needs. I think this is good though, since it cleanly moves things out of core and into plugins, which is quite nice. 😃

[thescientist13]

Added some docs and refactored to make plugin-livereload a Greenwood default server plugin (for now at least).

I will rebase this branch against the release/0.10.0 branch, but will let my changes stand until we can review during this week's meeting, at which point I think then this will be good to merge, barring any major objections.