Our second Open Source Love Day (OSLD)

A retrospective report of our second Open Source Love Day (OSLD). We present the results of our work on hudson and git and the lessons learnt.


Today we celebrated our second Open Source Love Day (OSLD). When we say “celebrated”, we actually mean that all of us worked hard and concentrated for hours, just to have a short meeting with candy at the end of the day.

The Open Source Love Day is our way to show our appreciation to the Open Source software development ecosystem. We heavily rely on Open Source products for our customer projects, so it’s just fair to donate back. You can read more about our motivation and specifica in our first OSLD blog posting.

For this day, we adjusted the rules a bit. While Object Calisthenics are very powerful in formulating rather academic software development values in some easy-to-remember rules, they just don’t fit well with existing projects. We still kept the rules in mind, but didn’t follow them strictly. We also learnt our share from last time’s experience of jumping right into the middle of arbitrary projects without a real need to do so. Today, we scratched more of our own itches.

You can participate at our OSLD by using the feature we’ve built today:

  • Hudson gets a brand new plugin. Currently, it’s in alpha status and needs some more nurturing, but is planned to be published within the next few weeks. The proof of concept was successful today. You will read more about it on this blog soon.
  • Another of our hudson plugins, namely the cmake builder plugin, got some feature love, incorporating suggestions from plugin users. We especially thank Ole B. for his feedback. The new features are checked in and will be available with the next plugin version 0.6, scheduled to be published in a few days. You’ll read the details about the new features here.
  • We’ve produced a feature implementation for hudson, adding the ability to use environment variables for the job’s workspace path. This feature touches core hudson functionality, so we just proposed a patch and leave it up to the core hudson team to decide on its inclusion. For more details, head over to the hudson issue tracker, entry #3997.
  • And we didn’t forget about git. As we are multi-IDE users (today’s development took place using NetBeans, IDEA and Eclipse), the EGit eclipse plugin for git will soon have the ability to diff the content of two revisions. An undocumented method argument took too much time to finish the feature today. After email communication with the project owner, the feature works on our machine, but needs some polishing before being committed in the near future.

As you can see, the hudson continuous integration server received a great share of our today’s love. It’s a great tool with a great community that really deserves our contributions.

What were our lessons learnt today?

  • While implementing the variable expansion feature, the author got distracted by a similar concept and followed this red herring. Namely, instead of a hudson.util.VariableResolver, we needed to use the hudson.EnvVars class. The EnvVars are pre-filled with all global variables like JAVA_HOME, while the VariableResolver is not. This could have been avoided by looking at the actual code instead of just type names. Once you think you’ve found your type, you read code the wrong way just to sustain your assumption.
  • To implement advanced plugin features, whether for hudson or eclipse, is a matter of skill with the “monkey see, monkey do” development style. Documentation is mostly non-existent or out-dated.
  • When handling HTML and HTTP in java, some survival tricks are crucial. Stay tuned for a whole blog post on that topic.
  • We still don’t feel comfortable within the JGit source code, as we still lack advanced git feature and terminology knowledge and the project lacks documentation. Our part of the problem will decline over time, as it’s a question of tool/mindset/slang exposure.

To sum it up, this OSLD worked out much better than our first one. We had more fun and yielded better results, mostly because we adjusted our goals to better suit our working style.

What are your experiences with open source development? Drop a comment!

Our first Open Source Love Day (OSLD)

opensourcelovedayLast week we had our first OSLD and started with the usual hopes and fears:

  • how much time will be consumed setting the project up?
  • will we find issues that are small enough to be finished in one day?
  • the hope to learn something new: a new technology, language or tool
  • the hope to improve our skills in reading a different code style and a new codebase

As an additional challenge we tried to do object calisthenics (which we will covered in a different blog post). In short they are a list of coding guide lines which try to bend your mind to get more flexible when coding/designing software.


After an initial meeting we decided to work on EGit/JGit. This project was on a familiar ground (Java) and had enough new tools (Git) and technologies (plugin development under Eclipse). Setup was very easy and fast (thanx to the EGit/JGit team!) and we started to look at the low hanging fruits linked from the EGit wiki which are basically issues that are categorized as easy. This is a very good idea for project newbies to start (in theory…). But the reality was that most of them were already patched and other had not enough information to make any sense for us (which could be also our lack of knowledge of the GIT wording and its internal concepts and function). At the end of the day we had worked on issues which were definitely too big for us (requiring changes in the infrastructure of JGit) and reported some issues as non-reproduceable.


So we learned a few things from the first day:

  • project setup can be very fast and easy
  • low hanging fruits are a very good idea
  • avoid infrastructure changes
  • a basic familiarity with the concepts involved is key to get along
  • don’t do too much on one day, instead: focus!
  • scratching your own itch would benefit the understanding of the issue and your motivation

So in the next month we give OSLD another chance and hope to learn even more.