lucisferre

“There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult.” —Sir Charles Antony Richard Hoare

Erlang Factory Lite Vancouver

Permalink

Last Saturday I spent my precious weekend enjoying the Erlang Factory Lite Vancouver edition, a one-day Erlang extravaganza.

Now, since I don’t know all that much about Erlang—I’ve only managed to complete the 7 languages in 7 weeks section on it, which culminates in creating Tic-Tac-Toe—I’ve kept a running blog of my notes throughout the talks, for later reference and afterwards distilled it down into the summaries you see below. So essentially I’m live blogging with a two-day time delay (a little trick I learned from NBC).

So lets get started…

Session 1: Noob to Production

James Golick of BitLove

James from BitLove (and Fetlife) talked about starting from scratch with Erlang and using it to build a concurrent chat service for Fetlife which at it’s peak can serve around 200k active conversation in browser tabs (I hope I got the right).

One of the main takeaways for me was from hearing about how James ran into a lot of trouble with the currently available OSS libraries for XMPP and even MySQL. The bottom line is the Erlang’s OSS ecosystem is still immature, which means you’re going to have to roll up your sleeves a bit and contribute. Interestingly enough James was not the only speaker who chose to build a custom messaging and presence library after finding ejabberd nearly impossible to work with.

The second big takeaway is the Erlang is both fast, very fault tolerant and very powerful for diagnosing problems when they do happen. James had a serious session timeout bug due to the defaults on the MySQL driver creating only one connection in the connection pool. Despite this problem the system continued to failover a restart and for the most part functioned. The bottom line is that Erlang’s code reloading and supervision features are a pretty big deal.

Session 2 - Mongo on Riak

Pavlo Baron

Pavlo’s talk centered around building a Mongo interface on top of Riak. A bit of this session focused on some of the MongoDB hate in the Erlang community. To be fair Pavlo had a point after showing some of the CPP code in the Mongo codebase which included magic numbers and some ridiculous commenting.

While I’m still not convinced MongoDB is nearly as bad as it’s made out to be—don’t get me wrong it’s miles away from perfect but it gets shit done and is great for quick prototype work with documents—I did start looking to Riak more seriously, long story short, it’s very cool.

Session 3 - Building Services with Webmachine

Kevin Smith of Opscode

Opscode is the company that brings you Chef. Kevin gave us a basic rundown of Chef’s architecture which was originally built using Merb, Ruby, Unicorn and Nginx for the server API. On average this works out to about 2.4GB per server running under Ruby which has motivated a shift to Erlang and Webmachine.

Webmachine is really very cool. It is essentially a REST toolkit built on top of Erlang. It’s based around defining resources as modules and setting up their RESTful behavior within the module. My only complaint was the lack of DRYness (a common problem with Erlang in general). Kevin’s solution to that was to create a kind of Erlang “mixin” which allowed them to reuse REST behavior code across multiple resources.

As expected there are no real facilities to support HATEOAS, a concept I feel is the unicorn of REST. Everyone thinks it’s wonderful but no one has ever actually seen it in the wild.

It also turns out there are other implementations of webmachine, including one in Ruby. I think if you want to keep the benefits of concurrency but also keep things “DRYer” I’d look at webmachine with Elixir (more on Elixir near the end)

Session 4 - Spawnfest: What I did on my Vacation

Mahesh P-Subramanya

Mahesh’s talk was on participating in Spawnfest while also on a diving vacation with is wife. A comedy of errors that still resulted in a solid entry in the form of Erlymob (currently down for maintenance) a flash mob organizing tools. The key learnings their experience doing this and involving a complete Erlang noobie:

  • OAuth Sucks
  • Strings != Binaries
  • ‘if’ is not ‘if’
  • Erlang syntax is easy but the semantics are hard
  • Immutable variables -> instant karma

Session 5 - Teaching Programming: Principles of Adult Learning

Casey Rosenthal

Casey gave a great talk on how he teaches programming to adults (including Erlang). He refers to the core technique as *Games where * is any language being taught. It works as follows:

  • Determine the relative experience of the participants
  • Inverse pair people with experience with people who are new
  • Provide a test problem or challenge
  • Facilitate the solution of the problem
  • Facilitate regular interruptions (every 25mins, sort of pomodoro style)

He also explained the basic principles behind adult learning, relevance, consilience and reflection. Information must have a relevant foundation to be retained, it can’t introduce too much cognitive friction with existing knowledge (consilience) and there has to be time for the learner to reflect on what has been learned.

Session 6 Erlang in Production

Geoff Cant

Geoff talked a bit about the benefits of Erlang vs X in production environments. This talk was a bit advanced for a noob like me, but did give me a good idea of the debugging and tracing features of Erlang.

The bottom line is Erlang is extremely powerful if you want to investigate problems that are occurring live in production.

Session 7 - Erlang without OTP

Jay Nelson

Erlang is typically used along with the “Open Telecommunications Platform” which provides a number of libraries and facilities that make things a bit easier. Jay is working on a different approach with his ErlangSP project and explained a little bit about how to build on Erlang without directly using OTP. Basically this was a whirlwind tour of what OTP does for Erlang.

Specifically, things like providing a framework for message pushing, async and sync messaging, controlled code change and fault tolerance and crash/termination handling. Jay explained this by showing what it would look like to write OTP compatible processes without actually using OTP.

Session 8 - The Erlang Microbrewery

Omar Yasin

Ok so this talk was not actually called that, but since I can’t remember what it was called and since Omar’s company Kodi is both a software shop and a fledgling microbrewery that’s the name I’m going with.

Omar talked about starting a financial software company after the Icelandic banking collapse and his team’s switch from .NET (the primary programming framework in Iceland at the time) to Erlang in creating their solution. All in all an interesting solution. As someone who has some experience moving away with .NET I’m always interested in hearing other peoples take on it from different angles.

Session 9 - Elixir

Yurii Rashkovskii of Spawngrid

Yurii presented on Elixir, which is essentially a meta-language on top of Erlang that appears to be inspired by Smalltalk/Ruby and Clojure. This was really interesting.

Erlang is a powerful tool and an interesting functional language, but it is also pretty old and lacks meta-programming facilities common to many of the more popular modern languages like Ruby. Elixir, currently being maintained by Jose Valim of the Rails core team seeks to address this.

I think that just like Coffeescript, it isn’t practical to use Elixir without first having a solid understanding of Erlang, but if you are planning on getting into doing some Erlang I would highly recommend checking out Elixir as well.

Summary

Finally, Tavis closed the conference with another awesome demonstration of coding by voice. I felt that this was a great way to start getting more familiarity with Erlang which has definitely been getting more and more attention from the web community as a whole.

As a polyglot, I think Erlang is definitely something you want to have at your disposal. There are definitely certain classes of problems it appears to solve extremely well. As a Lean/Post-Agile person who cares about continuous integration and deployment, verifiability and testability of systems and code, Erlang is first-class as well, supporting things like hot code reloading and live tracing and debugging of production.

So thanks Yurii and Spawngrid and all of the EFL sponsors. I’m confident I’ll be around next time EFL comes to town.

Comments