webpacker:output - outputs Rails.root

this makes the webpacker js config run a rake task to determine `Rails.root`.

It uses that to update the output path, otherwise, output is generated in manageiq-ui-classic/public/ instead of manageiq/public/

config/webpack/configuration.js

@@ -4,6 +4,7 @@ const { join, resolve } = require('path')
 const { env } = require('process')
 const { safeLoad } = require('js-yaml')
 const { readFileSync } = require('fs')
+const { execSync } = require('child_process')
 
 const configPath = resolve('config', 'webpack')
 const loadersDir = join(__dirname, 'loaders')
@@ -12,6 +13,10 @@ const devServer = safeLoad(readFileSync(join(configPath, 'development.server.yml
 const publicPath = env.NODE_ENV !== 'production' && devServer.enabled ?
   `http://${devServer.host}:${devServer.port}/` : `/${paths.entry}/`
 
+// override paths.output to use Rails.root
+const outputPrefix = execSync('rake webpacker:output', { encoding: 'utf8' }).trim();
+paths.output = join(outputPrefix, paths.output)
+
 module.exports = {
   devServer,
   env,

lib/tasks/manageiq/ui_tasks.rake

@@ -41,3 +41,10 @@ namespace :webpack do
     end
   end
 end
+
+# needed by config/webpack/configuration.js
+namespace :webpacker do
+  task :output do
+    puts Rails.root
+  end
+end