impact punk

Lego for grownups

Monday, 12 Oct 2015
Lenz Gschwendtner

When I think about building software I try to see where we need to end up in order to help the customer right now and then work backwards from there. Because I am really bad at knowing what customers want I mock up something that is good enough to get feedback and then morph it into working code and then robust infrastructure. At iwantmyname I have pushed for this since we started and for the most part we succeeded till we tried to grow up and “clean up” and “do things properly”. The result was the complete loss of the playfulness of our stack and a return to “work” instead of experimentation. We are currently fixing this and it is mainly a mindset thing.

We had an internal security audit recently and one of the outcomes was that our architecture is slightly ahead of its time, we do micro-services for at least 6 years by now and learned a lot about them. In this post I’ll talk a bit about how to go from mock code to robust infrastructure.

When a customer or we have an idea about a feature or a request or we see a lot of support in a specific area we want to invest a bit of time to implement an initial assumption about how we could address this. If it is easy to implement this and if it is simple to deploy this change then everyone in the team will be happy to make these little changes and over time we create a relevant product. Creating an environment where these changes have a low barrier is key in my view. It fosters ownership of the product across all parts of the company and helps create relevant products.

If adding a feature involves writing a project request, a few meetings, deployment windows, various iterations of accept/review/sign off cycles, then any experiment becomes a costly thing and that has two big drawbacks. First, it is not fun to experiment and therefor less experiments will happen. This means less and less features or improvements will hit the site over time. The second issue is the time and money sunk in an early assumption, This first draft is most likely not what your customers actually wanted but with all that investment it will most probably be the way they have to use that feature. Any change would need to go through the same cycle of project management and other things will always be more urgent.

How is it possible to go from a simple idea and mockup to working code that is scalable without much pain and without compromising security or reliability for the rest of the system. For us the answer was in a service oriented architecture or micro services or whatever the current buzz word for it is. We write every functionality on the site as a RabbitMQ endpoint that has a little daemon listing on it that implements that feature. To get a new feature out the door, we write a crude first version of what we think the functionality should be, mock up a bit of UI that interacts with that daemon and see how our customers like it. Over time that first crude prototype will morph into a nicer bit of code that is maintainable but because all bits of code are loosely coupled and the interfaces are just JSON messages via AMQP the internals of any daemon are not that important. The code quality can evolve over time and any bit can be replaced with new code even in new languages by just maintaining the external JSON interface. Also, and that is important, buggy code is limited to that daemon, no impact on the rest of the system. Mocking up an idea in code has no operational impact on the rest of the system and that makes it save to play.

This way, moving from an idea to a scalable and reliable part of the system is an easy progression, time and money is spent on the parts that need to be reliable and are actually used, the bits that are nice to haves get re-writes less often. Code evolves as part of the system. The system evolves as user behaviour changes over time. The system becomes an adaptable organism, code is killed off like old cells, new code is introduced as new experiments are done. It is a living thing, not a painstakingly architected, implemented and finally handed over to ops kind a system. We still have an architecture that we adhere to but it is as reduced as JSON via AMQP and two sorts of data stores. The rest is morphing over time and will change as our customers change.