An Architect's View

There's been quite a bit of buzz about ClojureScript since it's launch last July but it is a fast-moving target and a but daunting to get started with. Fortunately, there's a simple Leiningen plugin called lein-cljsbuild that can make it pretty simple to get up and running!

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I was very pleased today to get confirmation that my team are all going to Clojure/West in San Jose in March!

We've been a CFML house for a decade but we're using Clojure more and more on the back end to provide a high-performance, concurrency-safe foundation for our application. Back in December a couple of us attended Clojure/conj, with three days of Clojure training for one of our team. Now we're training up another team member on Clojure, and in March three of us will attend the Clojure conference, with training on Cascalog (big data analysis) for one of our team.

It's an exciting time to be a developer!

I was very pleased to get an email last night notifying me that my session proposal has been accepted for Clojure/West in March! Due to the number of high-quality submissions, I'll get a 25 minute slot instead of a 50 minute slot so that'll be quite a challenge and I'll have to narrow the focus of my talk to make it fit. Here's the original title and description - the talk will be a subset of this, yet to be decided:

Real World Clojure - Doing Boring Stuff With An Exciting Language

Clojure is often praised for its ability to tackle complex data problems and the glory goes to pattern matching, logic programming and massive scale (Storm, Cascalog etc) but what about real world problems? Is Clojure really only useful for hard problems?

In this session we'll take a look at using Clojure as a general purpose scripting language. World Singles has a multi-lingual, multi-tenant web platform for Internet Dating and we've adopted Clojure as our primary back end language. We'll look at solving real world problems - persistence, email, internationalization, configuration and environment control - ordinary problems, in ordinary applications, to see how Clojure can help you in your day-to-day life.

Given my association with clojure.java.jdbc, I'll probably focus mostly on that part of our usage but I hope to at least give a flavor of the other stuff we're doing with Clojure.

In years past, I have gone back over each month of my blog and posted a review of the year based on what I've been posting during the year. I skipped that for 2009 and 2010 for various reasons but decided to reinstate it this year because 2011 has been a very different year for me.

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As Clojure continues to evolve, it's a good idea to ensure your projects work with multiple versions of Clojure so that you are prepared for the future. Luckily, Leiningen makes that easy with a plugin called lein-multi which allows you to specify multiple sets of project dependencies and run tests against all of them automatically.

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Starting on December 5th and running for six weeks, the author of "Clojure in Action", Amit Rathore, is leading an online introduction to Clojure course for just $325. See the CodeLesson web site for more details on this Clojure course.

I'm fortunate that Amit is local to me so I've attended two of his one-day training courses already. In fact my first real introduction to Clojure was Amit's "ProClojure Bootcamp" back in May 2010 and it was a great jumpstart. More recently I attended his "Day of Macros" course which was pretty mind-blowing. Each of those cost $199, so the six week online course is great value since it will cover all of that and more!

If you're at all interested in Clojure, this would be an excellent way to come up to speed and find out what all the hype is about - for a very reasonable price!

It's pretty easy to get a Clojure web application up and running on Heroku. Heroku's Dev Center has a good Getting Started with Clojure article that shows you how to install the Heroku client and get your ssh keys setup. It has a very basic "Hello World!" Ring application as the example but you'll probably want something a bit meatier to play with. Here's how to get the FW/1 for Clojure example application running on Heroku...

Follow that Getting Started guide to get Heroku setup but when you get to the "Write Your App" section, do the following:

git clone git://github.com/seancorfield/fw1-clj.git
cd fw1-clj
heroku create --stack cedar
git push heroku master

You should see several screens of output flash past as Heroku downloads all the dependencies needed to build and run a FW/1 application and then you should see something like this at the end:

-----> Discovering process types
       Procfile declares types -> web
-----> Compiled slug size is 11.3MB
-----> Launching... done, v4
       http://some-domain-1234.herokuapp.com deployed to Heroku

Go to that URL in your browser and you should see the User Manager example application! (some-domain-1234 will be whatever domain Heroku has allocated for your web application)

After that, just edit your application, commit it, and push it up to Heroku. Heroku will update the dependencies if necessary and redeploy your application. It's that simple!

Now that FW/1 is available for Clojure, you might have looked at the examples that are in the FW/1 github repo and wondered how to create your own FW/1 application from scratch.

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The first episode of Chas Emerick's new Clojure podcast, Mostly Lazy was published today after being recorded yesterday morning. He picked me as his first interview "victim" (joke - see his follow up blog post wherein Chas clarifies that this is about community, not journalism!) and we covered a lot of ground in half an hour. Those who know me will be familiar with my focus on CFML / ColdFusion and that comes up in the podcast - if you don't know much about CFML (or your knowledge is based on old, outdated information), you might be in for a surprise as I talk about why I've used CFML so much over the last decade! [from around 13 minutes in]

After two years in the CFML world, FW/1 (Framework One) comes to Clojure!

Intended to bring the same simple, lightweight, convention-based MVC web application development that has proved so popular in the CFML world to the world of Clojure, FW/1 for Clojure is available on Clojars (0.0.2 right now). If you clone the github repo, you'll see a "user manager" example application which is a port of the same app from the CFML version of the framework. The documentation is, as always, a work in progress but covers the basic API and how to create a driver program for the framework in Clojure. More information on the rationale, approach and API of FW/1 can be found on the FW/1 (for CFML) wiki. I plan to adapt this for the Clojure version shortly...