Rename "roles" to "units". Put units in their own folders.

lib/units/app/middleware/webpack.js

@@ -0,0 +1,109 @@
+var path = require('path')
+var url = require('url')
+
+var webpack = require('webpack')
+var mime = require('mime')
+var Promise = require('bluebird')
+var _ = require('lodash')
+var MemoryFileSystem = require('webpack/node_modules/memory-fs')
+
+var logger = require('../../../util/logger')
+var lifecycle = require('../../../util/lifecycle')
+var globalOptions = require('../../../../webpack.config').webpack
+
+// Similar to webpack-dev-middleware, but integrates with our custom
+// lifecycle, behaves more like normal express middleware, and removes
+// all unnecessary features.
+module.exports = function(options) {
+  var log = logger.createLogger('middleware:webpack')
+  options = _.defaults(options || {}, globalOptions)
+
+  var compiler = webpack(options)
+  var fs = compiler.outputFileSystem = new MemoryFileSystem()
+
+  var valid = false
+  var queue = []
+
+  log.info('Creating bundle')
+  var watching = compiler.watch(options.watchDelay, function(err) {
+    if (err) {
+      log.fatal('Webpack had an error', err.stack)
+      lifecycle.fatal()
+    }
+  })
+
+  lifecycle.observe(function() {
+    if (watching.watcher) {
+      watching.watcher.close()
+    }
+  })
+
+  function doneListener(stats) {
+    process.nextTick(function() {
+      if (valid) {
+        log.info(stats.toString(options.stats))
+
+        if (stats.hasErrors()) {
+          log.error('Bundle has errors')
+        }
+        else if (stats.hasWarnings()) {
+          log.warn('Bundle has warnings')
+        }
+        else {
+          log.info('Bundle is now valid')
+        }
+
+        queue.forEach(function(resolver) {
+          resolver.resolve()
+        })
+      }
+    })
+
+    valid = true
+  }
+
+  function invalidate() {
+    if (valid) {
+      log.info('Bundle is now invalid')
+      valid = false
+    }
+  }
+
+  compiler.plugin('done', doneListener)
+  compiler.plugin('invalid', invalidate)
+  compiler.plugin('compile', invalidate)
+
+  function bundle() {
+    if (valid) {
+      return Promise.resolve()
+    }
+    else {
+      log.info('Waiting for bundle to finish')
+      var resolver = Promise.defer()
+      queue.push(resolver)
+      return resolver.promise
+    }
+  }
+
+  return function(req, res, next) {
+    var parsedUrl = url.parse(req.url)
+
+    var target = path.join(
+      compiler.outputPath
+    , parsedUrl.pathname
+    )
+
+    bundle()
+      .then(function() {
+        try {
+          var body = fs.readFileSync(target)
+          res.set('Content-Type', mime.lookup(target))
+          res.end(body)
+        }
+        catch (err) {
+          return next()
+        }
+      })
+      .catch(next)
+  }
+}