Smell if it’s well

Ever wondered how a code smell would taste like? We chose it to be like vanilla. Our latest extreme feedback device scents our office air depending on code quality.

We at the Softwareschneiderei are constantly searching for ways to gather feedback from our projects. We get feedback from our customers and their users, but we also get feedback directly from the code, be it through test results or code analysis. A great way to make your code speak for itself is to provide it some Extreme Feedback Devices (XFD).

IntroduciIMG_0574_smellng the Smell-O-Mat

One thing we always wanted to have was “code smells” that really smell for themselves. When we ran across an ultrasonic humidifier that can produce room-wide smells by dispensing essential oils, we found the right device for this feedback. We bought two humidifiers and labeled them “good” and “evil”. The hardest part was to find a smell everybody relates to “evil”, but won’t distract you too much from your work. Whenever our code analysis finds a new real code smell, the “evil” humidifier is turned on for some minutes. If an existing code smell is fixed, we get the “good” smell.

The effects

We do not produce code smells all too often. But once in a while, it happens. And this incident can now be perceived throughout the day just by breathing. On the other hand, fixing old smells is a source of refreshing air. Whenever the office atmosphere needs replenishment, all you have to do is to fix some code smells in our large code base (they do get rare!). Of course, most junior developers just open a window for that.

We chose grapefruit being our “good” smell, so our work area tastes mostly limony now instead of just “developer’s thoughts”, a fragrance that yet has to bottled.

The technical solution

Technically, the integration of the two humidifiers with our reporting infrastructure was very easy. Every XFD is controlled by an IRC bot that understands certain commands suitable for the device and hangs around at our central IRC server. As an humidifier only understands “on” and “off”, it could be controlled just like the ONOZ! lamp. We connected the humidifiers to a remote controlled power supply, switched it on and let the bot control the supply.

Our reporting infrastructure forwards its results to an aggregation software that interprets the numbers and produces IRC commands for the device bots. All of this is done with a combination of website scraping (Hudson as our continuous integration server has a wonderful XML API) and IRC messaging.

The history of XFD so far

Over the last years, we gathered XFDs for almost every human sense. We have visual effects, audible feedback using speech synthesis and even bought an USB rocket launcher for forced feedback needs. With the Smell-O-Mat, we can now deal with smelling, too.
The last human sense we have to address is tasting. Plans for the “coffee salter” were impeded by our sense of humanity. We keep searching.

Read more about our Extreme Feedback Devices:

Give your project a voice

We are all very into Extreme Feedback Devices (XFD), so we decided to use all our senses to gather feedback from our projects. This becomes a real challenge once you think about it, because we are naturally very focused on (and limited to) visual feedback.

So we decided to put audible feedback to work.

All our projects get continuously built by two servers in parallel. The first server checks for compilation and test errors, just like a good CI server should. The second server applies every quality metric we found helpful to the code and spits out huge amounts of numbers for every single build.

We identified the numbers that really matter to us and established a simple mechanism to scrape them from the result web pages. Then we associated a sound sample with all possible changes and plugged some speakers to our feedback server.

So now, expect our projects to clearly articulate their news.

To give you an idea of how it sounds, here’s a short list of possible audio samples:

  • Fixed an important bug: “Impressive”
  • Reduced code crap: “Excellent”
  • Introduced a bug: “Humiliation”

Imagine the words spoken like in an old Quake game. Now you can have an eventful build and be yelled at like “Impressive Excellent Humiliation”.

We reserved the biggest coding failure we can imagine happening here to a special audio sample. If somebody introduces new code crap (as determined by Crap4J), he gets ordered to “CUT THE CRAP!” at incredible volume. We used the voice of the inventor of XFDs, Alberto Savoia, taken from his delightful training video for management by numbers (position 2:03ff). The audio quality isn’t convincing, his command surely is.

If you wonder what it’s like to be suddenly interrupted by different voices rebuking or praising you – it’s healthy. You get used to it very quickly, yet the information always catches on. And the information is always relevant.

We call it our “audible remorse”.

Read more about our Extreme Feedback Devices: