Migration to Webpack


Currently we use require.js module loader, AMD modules format and r.js build system. We’ve been using these technologies from the very beginning (more than 3 years ago!) and now they seems to be outdated and causing lots of problems during development. Migration to webpack is going to solve most of them.

Problem description

Current require.js-based build approach has the following issues:

  • Different approaches for nodejs and in-browser compilation of styles and JS - this doubles efforts to support them and doesn’t guarantee that a change made in dev environment will work in production. Some transformations (like CSS-autoprefixer) are even not possible (or very hard to setup) in browser. Webpack uses single approach for every environment.
  • Long in-browser compilation time. On my laptop I have to wait about 10-15 seconds after hitting F5 for loading and compilation. Webpack allows hot updates without refresh which take effect in 1-2 seconds.
  • Inability to use original LESS styles from twitter bootstrap. With require.js we have to use precompiled CSS styles (attempting to load LESS styles directly results in extra 20s of compilation time). With webpack we can use original styles with minimal impact on performance.
  • With require.js too granular modules may lead to longer loading times. Thus we currently try to put as many related stuff to a single module as possible, which has impact on unit-testing as we usually expose only 1 component from a module. Webpack will eliminate such limitation.
  • ES2015 - webpack allows us to write code using ES2015 syntax and use ES2015 modules (official JS modules standard). It’s hardly achievable with require.js - we have to use AMD and ES5.

Proposed changes

Web UI

  • Replace require.js build stack with webpack.
  • Replace Intern for unit-tests with Karma: Intern doesn’t have support for wepback, only AMD modules are supported.
  • Set up webpack-dev-server for developer convenience - it provides lots of useful options such as hot reloading, incremental builds, etc.


Data model





RPC Protocol


Fuel Client




Fuel Library



  • Do nothing and keep require.js stack.
  • Use CommonJS/browserify - though for our project setup would be more complicated and would miss some webpack-specific features (like React hot reloading)

Upgrade impact


Security impact


Notifications impact


End user impact


Performance impact

  • Applying changes in dev mode will become much faster due to hot reloads and incremental builds.
  • Unit tests will run slower - build is needed before starting the tests.
  • Production UI build will become ~2 times faster.

Deployment impact


Developer impact

Developer must manually compile UI by running gulp build after fetching updates - otherwise previously compiled UI will be used. As an alternative, developer may want to use webpack-dev-server.

Infrastructure impact

Quite a few new NPM packages (webpack itself, loaders, etc.) should be added. Blueprint package-for-js-modules needs to be implemented to speed up this procedure.

Documentation impact

Development documentation should be updated accordingly.



Primary assignee:
Other contributors:
Mandatory design review:
vkramskikh@mirantis.com jkirnosova@mirantis.com astepanchuk@mirantis.com

Work Items

  • Remove require.js artifacts and make build work.
  • Set up build task.
  • Set up dev-server task.
  • Set up karma for unit tests.



Testing, QA

UI functional tests involve UI compression, so after switching to webpack they must work without any changes.

Acceptance criteria

  • There should be no dependency on require.js.
  • UI unit tests should work.
  • UI functional tests should work.
  • Development documentation should be updated.
  • Development server with live reload should work.