ClojureD conference in Berlin

In the end of February five Siilis took off from Helsinki to visit Berlin. ClojureD conference to be exact. Two tracks, plenty of talks and focus in Clojure. This is an overview from the talks that we visited and because Joy Clark had awesome notes on talks too I asked permission to share her notes here as well. Big thumbs up for the visual content!

Teaching Clojure

For me the first talk of the day was about teaching. We have ran our junior program with Clojure for two years as we speak so new views and how others find teaching in this domain was interesting. Mike Sperber shared his point on systematic thinking and how it affects the way we build software.


Recap in drawing from Joy Clark

Maria: a beginner-friendly coding environment for Clojure

Next talk was about Maria by Dave Liepmann. A simple really beginner friendly place to learn fundamentals in Clojure. In his talk there was quite a few demos on how fast one can get on with coding.

Fast results are important when you start something new and Maria offers fast response to your coding and shows results immediately. Of course when you start doing bigger and more advanced stuff your pace of getting things done and ready will be different.


Recap in drawing from Joy Clark

 Writing test that suck less

Last talk before lunch was about testing by Torsten Mangner. This talk dived a little deeper to the fundamentals of testing. Talk began wit a confession and gave us the baseline.

“Writing unit tests in Clojure is easy, since testing pure functions is trivial. But the more high-level our tests become, the more they have to deal with the state and side-effects of your application. It becomes harder and harder to write proper tests. And worst of all: they are harder and harder to understand and to maintain, greatly diminishing the value of those tests as a documentation of your software.”


A Dynamic, Statically Typed Contradiction

After lunch we had the pleasure of diving into mathematics. As Andrew Mcveigh talked about lambda calculus and its application in a “Hindley-Milner“ based type system and how it can be mapped onto Clojure. This solution can also be used to “type-chec” a subset of Clojure code.

Unfortunately my attention was to fully hang on with the maths and our ways with Joy had departed so, no good pictures from this talk. Sorry!

Onyx, virtual machines, jokes and afterparty

Next up for me was Vijay talking about Onyx and its uses for data crunching. An overall look for the uses. Masterless systems, stream and batch processing, flow control and principles of Clojure.

After coffee we got the pleasure of seeing a walkthrough how to implement Clojure on a new virtual machine. Heavy stuff and a great idea.

Last official talk before the lightning talks (I had to skip those because I was hungry and needed a Döner 😉 ) was called defjoke. Live coding a fully compliant spec for humour.

All talks were taped and are available soon in check it out. Other great photos and one-liners can be found in

Thanks from Siili to great organisers and speakers. Hoping to see you soon in other adventures!




Thoughts on Tampere Goes Agile 2017

Last weekend (27th-28th October) I had the honour to attend Tampere Goes Agile as a speaker and guest. This was my first speech in agile conference and I was of course a bit nervous about it. On Friday night we met with other speakers to discuss about next days conference. We got an unfortunate information that the closing keynote will be cancelled. During our dinner we planned the ending of the conference to be a panel discussion around the topics that we found controversial among us. That decided we chose panelists and yours truly was also included. Well, I was anyways going to be nervous the whole day so why not.


Saturday started with opening keynote from Mika Turunen on gaining speed for teams. After that I headed to hear what Artur Margonari had to say. His talk was about using and customising existing frameworks and models for agile transformation. Interesting talk how he had applied SAFe®, LeSS with bits and pieces from Spotify’s ways of working. He stated that using best fitting parts for the problem at hand. In his work that worked fine and added transparency between teams and management.

Another interesting speech was about fixed price projects by Teemu Toivonen. He underlined the fact that even within the fixed scope projects can be done in agile way. A lot of the effort goes to managing expectations. You can’t predict the future and the further you go the harder even guessing goes. Or can you tell what is going to happen in next 10 months? If you keep your time for development short your guesses have better odds to be right and responding to changes is possible.

My topic was how to turn negative emotions within the team to a positive goal. Starting from individual level. Starting with finding your problem from distant feeling that something is off. After that working our way towards a happy productive team that wants to develop and move forward. I talked about avoiding the problems that occur when going through this process. There are many of them and I cant say that I included them all to my speech. Well, it’s still a start.



In total Tampere Goes Agile was a pleasant experience. I met a lot of nice folks and was surprised that many of the themes that used to be ignored were actually a subject to a true discussion. Not just for shouting opinions pro and against.

What can we expect in future? In the closing panel I said: I hope something new and better comes and clears the table. This does not mean that everything old is bad and must go. But as we are constantly changing and improving, there should be new way just around the corner. And of course, we want to be a part of it. Hopefully we can help. At least I don’t want to be the one who holds back change.