Rally Github Integration

Rally Software allows its engineers 6 weeks of hackathon per year. Hackathon give developers a chance to hack on whatever projects and technologies excite them. This past hackathon my teammate Jacob Burton and I used Rally's App SDK 2.0 preview and Github's REST api to create a Github integration app that runs inside of Rally. It's pretty cool because users can view their commits and diffs without ever having to leave Rally's interface. Checkout the app here:

• Screencast Demo: http://www.screencast.com/t/Nr9vXXvCz
• App: https://github.com/RallyCommunity/RallyGithub

Over this past weekend Rene Saarsoo helped me integrate some code changes into JSDuck, a javascript documentation generator. The changes I added allow users to discover and run all of the inline example code for javascript Class documentation, and will report back any failures. The extension is activated by including the flag "--doctests" when executing jsduck from the command line. The code is available from the doctests branch.

This is a cross post from: Rally Engineering Blog

Sometimes I run across a task where I need to attach event listeners to many different dom elements of the same type. I am usually tempted to do something similar to the code below.

Ext.each(Ext.query('a', parentNode), function(el) {
    el.on('click', doSomethingAwesome);
});

This is ExtJs's way to loop through each dom element matching the passed css selector and attach an event listener to it. I'm lazy and it's less code than the correct implementation, which would be to add a listener to the parent element and filter for the correct target element inside the handler function. The disadvantages to the lazy method are that multiple listeners are created, all of which have some amount of overhead attached, and that listeners need to be removed and/or reattached whenever the innerHTML of the parent element changes.

An ExtJs specific example of when the 'lazy' method doesn't work is when event listeners need to be attached to elements created by a renderer inside of a GridPanel cell. The GridPanel does not expose any row or cell render events, so there is no reliable way to add event listeners to dom elements located inside cells.

Fortunately ExtJs's Element.on method has a helpful 'delegate' option that does all of this for you automatically. Use ExtJs's Element.on method to attach a listener to the parent dom element and specify a css selector for the 'delegate' option to filter out events whose target node does not match the passed css selector.

var parentEl = Ext.fly(parentNode);
parentEl.on('click', function(event, target, options) {
    console.log('the "target" argument is the anchor element that is a child of parentNode');
}, this, {
    delegate: 'a'
});

AmFast 0.5.3 Released

AmFast version 0.5.3 has been released. This release contains several important bug fixes. The code can be downloaded from PyPi or checked out from SVN.

ExtJs Component Config

Cross post: ExtJs Component Config

Testing With Browser Mob

The Project

I recently got the chance to work on a project using BrowserMob for automated testing.  BrowserMob allows you to run Selenium test scripts "in the cloud". In my case I was not testing functionality, but instead  testing performance of a Flex app. I needed to test latency and throughput of messages being dispatched through the Flex messaging system via http://code.google.com/p/amfast/. This proved very difficult to test locally, but was a snap with BrowserMob.

The Testing

I created a simple Flex client to send and receive Flex messages in a way that replicated a production environment. I also created a custom server component to replicate the production environment and to help log message data to be analyzed later. After getting the client and server running locally, I signed up for a BrowserMob account and launched several browsers with their web interface.

The whole process was simpler than it should have been, and I was very impressed with how well it worked. I highly recommend trying out but BrowserMob for performance and load testing applications, and I'm hoping to get a chance to try out running more full featured automated functional tests in the future.

Paired Programming

Rally encourages its engineering staff to post to the company blog, so I decided to write a little about my initial experience with paired programming. TLDR: paired programming is better than I expected, increases code quality, and probably productivity.