Caution

Buildbot no longer supports Python 2.7 on the Buildbot master.

3.2.11. Base web application

3.2.11.1. JavaScript Application

The client side of the web UI is written in JavaScript and based on the AngularJS framework and concepts.

This is a Single Page Application. All Buildbot pages are loaded from the same path, at the master’s base URL. The actual content of the page is dictated by the fragment in the URL (the portion following the # character). Using the fragment is a common JS technique to avoid reloading the whole page over HTTP when the user changes the URI or clicks a link.

AngularJS

The best place to learn about AngularJS is its own documentation.

AngularJS strong points are:

On top of Angular we use nodeJS tools to ease development

  • webpack build system, seamlessly build the app, can watch files for modification, rebuild and reload browser in dev mode. In production mode, the build system minifies html, css and js, so that the final app is only 3 files to download (+img)
  • pug template language (aka jade), adds syntax sugar and readability to angular html templates
  • Bootstrap is a CSS library providing know good basis for our styles
  • Font Awesome is a coherent and large icon library

Additionally the following npm modules are loaded by webpack and available to plugins:

For exact versions of these dependencies available, check www/base/package.json.

Extensibility

Buildbot UI is designed for extensibility. The base application should be pretty minimal, and only include very basic status pages. Base application cannot be disabled so any page not absolutely necessary should be put in plugins. You can also completely replace the default application by another application more suitable to your needs.

Some Web plugins are maintained inside buildbot’s git repository, but this is not required in order for a plugin to work. Unofficial plugins are possible and encouraged.

Typical plugin source code layout is:

setup.py
Standard setup script. Most plugins should use the same boilerplate, which implements building the BuildBot plugin app as part of the package setup. Minimal adaptation is needed.
<pluginname>/__init__.py
The python entrypoint. Must contain an “ep” variable of type buildbot.www.plugin.Application. Minimal adaptation is needed
webpack.config.js
Configuration for Webpack. Few changes are usually needed here. Please see webpack docs for details.
src/...
Source code for the angularjs application.
package.json
Declares npm dependencies and development scripts.
MANIFEST.in
Needed by setup.py for sdist generation. You need to adapt this file to match the name of your plugin.

Plugins are packaged as python entry-points for the buildbot.www namespace. The python part is defined in the buildbot.www.plugin module. The entrypoint must contain a twisted.web Resource, that is populated in the web server in /<pluginname>/.

The plugin may only add a http endpoint, or it could add a full JavaScript UI. This is controlled by the ui argument of the Application endpoint object. If ui==True, then will automatically load /<pluginname>/scripts.js and /<pluginname>/styles.css into the angular.js application. Additionally, an angular.js module with the name <pluginname> will be registered as a dependency of the main app module. The scripts.js file may register some new states to $stateProvider or add new menu items via glMenuProvider for example.

The plugin writers may add more REST apis to /<pluginname>/api. For that, a reference to the master singleton is provided in master attribute of the Application entrypoint. The plugins are not restricted to Twisted, and could even load a wsgi application using flask, django, or some other framework.

Please look into the official BuildBot www plugins for examples. The www/grid_view and www/badges are good examples of plugins with and without a JavaScript UI respectively.

Routing

AngularJS uses router to match URL and choose which page to display. The router we use is ui.router. Menu is managed by guanlecoja-ui’s glMenuProvider. Please look at ui.router, and guanlecoja-ui documentation for details.

Typically, a route registration will look like following example.

   class MyState {

        // Dependency injection: we inject $stateProvider and glMenuServiceProvider
        constructor($stateProvider, glMenuServiceProvider) {
            // Name of the state
            const name = 'myname';
            const caption = 'My Name Plugin';

            // Configuration
            glMenuServiceProvider.addGroup({
                name: name,
                caption: caption,           // text of the menu
                icon: 'exclamation-circle', // icon, from Font-Awesome
                // Order in the menu, as menu are declared in several places,
                // we need this to control menu order
                order: 5
            });
            const cfg = {
                group: name,
                caption: caption
            };

            // Register new state
            const state = {
                controller: "myStateController",
                template: require('./myname.tpl.jade'),
                name: name,
                url: `/${name}`,
                data: cfg
            };
            $stateProvider.state(state);
        }
    }

angular.module('mymodule')
.config(['$stateProvider', 'glMenuServiceProvider', MyState]);

Directives

We use angular directives as much as possible to implement reusable UI components.

Linking with Buildbot

A running buildmaster needs to be able to find the JavaScript source code it needs to serve the UI. This needs to work in a variety of contexts - Python development, JavaScript development, and end-user installations. To accomplish this, the www build process finishes by bundling all of the static data into a Python distribution tarball, along with a little bit of Python glue. The Python glue implements the interface described below, with some care taken to handle multiple contexts.

See Hacking the Buildbot JavaScript for a more extensive explanation and tutorial.

3.2.11.2. Testing Setup

buildbot_www uses Karma to run the JavaScript test suite. This is the official test framework made for angular.js. We don’t run the front-end testsuite inside the python ‘trial’ test suite, because testing python and JS is technically very different.

Karma needs a browser to run the unit test in. It supports all the major browsers. Given our current experience, we did not see any bugs yet that would only happen on a particular browser this is the reason that at the moment, only the “Chrome” is used for testing.

Debug with karma

console.log is available via karma. In order to debug the unit tests, you can also use the global variable dump, which dumps any object for inspection in the console. This can be handy to be sure that you don’t let debug logs in your code to always use dump

Testing with real data

It is possible to run only the frontend and proxy the requests to another BuildBot instance. This allows skipping the setup of a BuildBot installation of appropriate complexity and just using already existing one.

This is implemented as the www/base/frontend_proxy.js nodejs script. To run it, setup and enable a virtualenv like described in Create a Buildbot Python Environment. Then execute the script as follows:

cd www/base
nodejs fontend_proxy.js --host <buildbot_host> --port <localhost_port>

You can then just point your browser to localhost:<localhost_port>, and you will access http://<buildbot_host> with your own version of the JavaScript UI.

If your buildbot instance is served over HTTPS, use the --secure argument to access the host via https:// and wss://, respectively. The argument --ignoresslerrors may be helpful if the server uses a self-signed certificate. Note that the --host parameter can specify port and URL path, in case buildbot is served on a non-standard port or not from the root path /.

nodejs fontend_proxy.js --host ssl-protected.ci.example.com --secure
nodejs fontend_proxy.js --host self-signed-ssl.ci.example.com/buildbot \
    --secure --ignoresslerrors