Compatible with Webpack multi builds?

[joshhunt]

We're using Webpack in it's multi-build setup, where the config is an array of webpack configs:

module.exports = [
 { output, resolve },
 { output2, resolve2 },
]

When we configure both the configs to use Happypack, only one configuration starts and runs.

Any ideas on what's happening? Is this a tested/support configuration?

[amireh]

Is this a tested/support configuration?

First time I've heard about this feature, no I haven't really tested this.

Any ideas on what's happening?

It could be that if webpack is creating only 1 compiler for those builds then HappyPack will run only on the first build, because right now it's coded to stop after the initial build unless we're in watch mode (and in this case, we're not in watch mode, but there are two "initial" builds.)

That's just a wild guess though. We can take a look at this.

[gnz00]

I'm not too familiar with the multi-compiler mode in Webpack, but if it helps at all, here is how I'm running concurrent builds (with HappyPack) for 12 different environments:

gulp.task('compile:all', function(done) {
  const promises = configs.map(
    config => new Promise((resolve, reject) => {
      webpack(config, (err, stats) => {
        if (err) reject(err);
        else resolve(stats)
      })
    })
  )

  Promise.all(promises)
  .then(stats => done(null))
  .catch(error => done(error))
})

There are some issues with process file limits on OS X. Might be worth looking into spawning child processes or some other workaround.

[amireh]

I've just tried this in a simple example and it seems to work fine for me. Make sure you're not using shared thread pools between the builds since each provides a different compiler and that won't work.

var path = require('path');
var HappyPack = require('../../');
var HAPPY_LOADER = path.resolve(__dirname, '../../loader.js');
var IDENTITY_LOADER = path.resolve(__dirname, './identity-loader.js');

module.exports = [
  {
    entry: path.resolve(__dirname, 'lib/a.js'),

    output: {
      path: path.resolve(__dirname, 'dist'),
      filename: '[name].js'
    },

    plugins: [
      new HappyPack({
        id: 'happy-build-1',
        loaders: [ IDENTITY_LOADER ],
        threads: 2
      })
    ],

    module: {
      loaders: [
        {
          test: /\.js$/,
          loader: HAPPY_LOADER + '?id=happy-build-1',
        }
      ]
    },
  },

  {
    entry: path.resolve(__dirname, 'lib/a.js'),

    output: {
      path: path.resolve(__dirname, 'dist-2'),
      filename: '[name].js'
    },

    plugins: [
      new HappyPack({
        id: 'happy-build-2',
        loaders: [ IDENTITY_LOADER ],
        threads: 2
      })
    ],

    module: {
      loaders: [
        {
          test: /\.js$/,
          loader: HAPPY_LOADER + '?id=happy-build-2',
        }
      ]
    },
  }
];

Closing this since I can't reproduce and no context was provided.

[jmmendivil]

Here:

webpack.config.js

'use strict'
const path = require('path')
const webpack = require('webpack')
const commonConfig = require('./config.js')

let configs = []

const common = commonConfig()

const config1 = Object.assign(
  {},
  common,
  {
    entry: './app.coffee',
    output: {
      path: path.join(__dirname, 'dest'),
      filename: 'mobile.js' 
    },
    plugins: common.plugins.concat(
      new webpack.DefinePlugin({
        ENV: JSON.stringify('mobile')
      })
    )
  }
)

configs.push(config1)

const config2 = Object.assign(
  {},
  common,
  {
    entry: './app.coffee',
    output: {
      path: path.join(__dirname, 'dest'),
      filename: 'desktop.js' 
    },
    plugins: common.plugins.concat(
      new webpack.DefinePlugin({
        ENV: JSON.stringify('desktop')
      })
    )
  }
)
configs.push(config2)

module.exports = configs

config.js

'use strict'
const HappyPackPlugin = require('happypack')

module.exports = () => {
  return {
    module: {
      loaders: [
        { test: /\.coffee$/, loader: 'happypack/loader?id=coffeescript'  },
      ]
    },
    plugins: [
      new HappyPackPlugin({
        id: 'coffeescript',
        threads: 4,
        loaders: ['coffee-loader'],
        verbose: false
      })
    ]
  }
}

app.coffee

console.log 'ENV: ', ENV

expected: dist/mobile.js and dist/desktop.js

[amireh]

Try to avoid reusing the common config instance.. just create the common config twice since it's a factory anyway, a la:

const config1 = Object.assign({}, common(), { ... });
const config2 = Object.assign({}, common(), { ... });

Then you end up with 2 actually unique HappyPlugin instances as opposed to sharing one.