Episode 11 with Jim Crossley and Toby Crawley: the Immutant two-step

jcrossleytobyToby Crawley (@tcrawley) and Jim Crossley (@jcrossley3) (shown to the left, respectively), among other things, are the primary instigators behind Immutant, the Clojure application platform built on top of the JBoss Application Server.  The tl;dr on Immutant is that it provides many of the same infrastructure services that many “platforms” provide (e.g. clustered queuing, caching, distributed transactions, etc), but with a single set of well-integrated Clojure APIs that you can (relatively) easily deploy and manage on your own infrastructure.

Further, regardless of the project, Toby and Jim are always good company; it was a hoot to hang out with them for a spell! We had a great time, I hope you enjoy listening in…

(Recorded on November 16th, 2013; my apologies to Jim and Toby for the particularly bad latency on the release of the recording.)


Or, download the mp3 directly.

Discrete Topics

(Remember to follow @MostlyLazy so you know who’s going to be on next, and can send us topics and questions!)

  • All about Immutant…
    • (…which Chas happens to use as a foundation for Docuharvest, yet another of his side projects)
  • “Platform as a service” services, e.g. Heroku & Elastic Beanstalk
  • Grizzly, a Java-based HTTP server designed to be embeddable (much like Jetty), which happens to be used as the basis for Glassfish’s web stack
  • Using nREPL and all the middleware available for it (like Piggieback via Austin for ClojureScript REPL-ing) in conjunction with Immutant
  • clojurescript.test, a maximal port of clojure.test to ClojureScript
  • double-check, a fork of Reid Draper’s simple-check property/specification testing library that can be used portably in both Clojure and ClojureScript
  • Plans for Immutant 2.0, a.k.a. “The Deuce”
  • The Immutant mascot (inspired by the Hypnotoad), probably the best thing to ever come out of a JIRA ticket:
  • TorqueBox, the Ruby application platform built on top of JBoss, analogous to Immutant
  • Chas’ various Immutant hacks around programmatic queue and logging configuration (the former of which is apparently slated for addition to the official API in some form)
  • Infinispan (JBoss’ distributed in-memory key-value store) & Hotrod (its wire protocol for un-clustered client communication)
  • Shout-out to Bob McWhirter, founder of the ProjectOdd group at Red Hat (which houses Immutant, Torquebox, and others)
  • Caribou, a “dynamic web application generator with antlers”, one of the latest entries in the Clojure web framework explosion
  • Clojure Conj 2013 “recap”
  • vert.x, an “asynchronous polyglot application platform for the JVM”, and the Clojure vert.x support, which Toby wrote/maintains and talked about in his Conj talk
  • Recent fixes to Clojure (which landed in 1.6.0 alphas) to prevent memory leaks in dynamically-deployed applications
  • /ht Andy Fingerhut and Alex Miller for their recent contributions to the Clojure development process, etc.
  • ClojureScript releases are versioned in an “interesting” way, e.g. 0.0-XXXX instead of X.Y.Z. Toby asks, “Why, why, why‽”.
    • The mentioned mailing list post where this versioning scheme originally arose is here, and the ongoing documentation of it looks to be here.
  • Results from the 2013 State of Clojure and ClojureScript
  • Michael Fogus’ post and talk about the ClojureScript compiler pipeline
  • cljx, an implementation of “feature expressions”, enabling one to target both Clojure and ClojureScript from a single codebase
  • Not much of a news flash, but Mac OS X is no longer a reasonable option for (some, many?) software developers. What follows is some navel-gazing on our collective migration to Linux.
  • Powercenter 120, the first computer that Chas bought new
  • Russ Olsen’s “To the Moon” Conj 2013 talk


Just prior to finishing these show notes, I asked Jim and Toby what pictures of themselves they wanted to go along with the episode. Their (mostly) prosaic, perfectly-fine twitter avatar headshots came first, but then Jim was kind enough to direct my attention to this gem:


Yes, that’s a kitten t-shirt / patriotic fanny pack ensemble. Don’t mind the haters, Toby, this is why we love you.

Episode 0.0.5: Chris Houser at Clojure Conj 2011

Recorded November 12th, 2011, the fourth and final recording in a series of conversations from Clojure Conj 2011.

Chris Houser (usually known as chouser online) has been working with Clojure longer than nearly anyone else; he started tinkering with the language in early 2008, and was a fixture in #clojure irc and on the mailing list for years.  His contributions to the language, early libraries, and community through his always genial and insightful presence are hard to overstate.  More recently, he has coauthored the excellent Joy of Clojure along with Michael Fogus, and is now working with Clojure daily over at Lonocloud.

It’s been my privilege to know and work with Chris a bit over the years, and, as always, it was great to talk with him in person.



Or, download the mp3 directly.

Discrete Topics

  • “Everything I learned, I [learned] on irc?!”
  • Macros (a.k.a. “compile time metaprogramming”) in Scala? Project Kepler
  • Rich Hickey once made a visit to the Western Mass. Developer’s Group, and delivered one of his great early talks on Clojure, complete with an ants demo.  My post on the event, and video.
  • “Tooling is a canard.”
  • Chouser wrote “the first ClojureScript” years ago, a proof of concept using JavaScript as a host for a Clojure implementation.  (Don’t go looking for it, I think it’s dropped off the internets by now; check out the “real” ClojureScript if you want a Clojure for JavaScript.)
  • error-kit — don’t use that though, you should almost surely use Slingshot instead for advanced error handling

Episode 0.0.4: Antoni Batchelli and Hugo Duncan at Clojure Conj 2011

Recorded November 12th, 2011, third in a series of conversations from Clojure Conj 2011.

I caught up with Hugo Duncan and Antoni Batchelli (everyone calls him Toni 😉 during one of the lunch breaks at the Conj.  These guys have been on a tear with Pallet, an open source Clojure project that Hugo started in early 2010 to shave one of the hairiest yaks around, the automation of provisioning and management of computing infrastructure.  The result is a tool and library that provides a classically Clojure abstraction for controlling nearly any environment, from cloud nodes to virtual machines to the rackmounts you have downstairs.  Since it is their full-time job — Toni and Hugo have built a business around the project — most of our discussion centers on Pallet, its history, and how people are using it.

Near the end, Hugo and I talk some about his other work in the Clojure world, which has generally been related to tooling around Emacs and Maven.



Or, download the mp3 directly.

Discrete Topics

  • Clojure/West, happening March 16-17, 2012 — be there!
  • Disclojure, a great stream of links to Clojure tutorials and news maintained by Toni
  • Pallet, representing computing infrastructure with Clojure abstractions
    • Chas has used pallet to automate provisioning and configuration of Clojure webapps and CouchDB clusters (old, OLD links!)
    • Often mentioned in the same breath as Chef and Puppet on the now-defunct IT Management and Cloud Podcast (by Michael Cote and John M. Willis)
    • Storm, by Nathan Marz @ Twitter — uses pallet to simplify deployment and operations
    • pallet-hadoop — uses pallet as a library to automate hadoop operations
    • Support for tons of different computing infrastructures:
      • jclouds — provision & control resources on dozens? of different clouds
      • vmfest — layer on top of VirtualBox that allows you to use it as a local cloud “provider”
      • node-list — control non-cloud computing infrastructure, i.e. in-house resources
    • AWS’ Elastic Beanstalk
    • GoGrid (using Clojure because of Pallet!)
  • swank-clojure
  • JPDA (Java Platform Debug Architecture), includes the Java Debug Interface
  • Clojure Debug Toolkit
  • Alternative Maven support for Clojure, written in Clojure: zi
  • clojure-maven-plugin (by Mark Derricut a.k.a. talios)
  • Leiningen


This episode’s outro is a piece by Christopher Ford. Using a synthesized cornet by Jennifer Smith, he produced an abbreviated version of a piece where a set of chords continually fall out of time with a simple five-note melody.  Of course, full source to the piece is available for your Overtone hacking delight.

Episode 0.0.3: Chris Granger at Clojure Conj 2011

Recorded November 12th, 2011, second in a series of conversations from Clojure Conj 2011.

I had a chance to sit down with Chris Granger on the last night of the Conj.  It’s been fun to watch him over the past months put out a set of really pleasant-to-use and extraordinarily well-documented and well-packaged libraries, and he’s turned into a great presence around the Clojure sphere in general.  Chris works with Clojure daily for his current employer, ReadyForZero — a Y Combinator-funded startup that helps people get out of debt — where he helped port a Python & Django codebase over to be 100% Clojure.  (Yup, the big tagline for this episode is, “Y Combinator startup bets business on Clojure!” 😉  In addition, he has a unique history, having recently worked as a program manager Microsoft, working on Visual Studio…so, our discussion was wide-ranging.

After we recorded this, it was announced that Chris will be teaching two training sessions on Clojure web development at the new Clojure/West conference in March.  If you’re new to Clojure and want to jump-start your skills for it in the web space, signing up for one of those sessions would likely be a good way to get further faster.


(BTW, don’t miss the notes on the Overtone-produced intro and outro below…)


Or, download the mp3 directly.

Discrete Topics

  • Chris is known as ibdknox on Twitter and elsewhere
  • Lead developer for:
    • Noir, a web microframework that sits on top of Ring and Compojure
      • similar in spirit to Ruby’s Sinatra, provides “sensible defaults”
    • Korma, a Clojure abstraction over SQL (notan ORM!)
      • Efficiently write composable SQL in Clojure
      • similar to LINQ to SQL, Python’s sqlalchemy
      • (We used Korma for some RDBMS examples in the book! — Chas)
    • Pinot, a ClojureScript companion to Noir
      • Clojure-idiomatic browser DOM manipulation (instead of using gclosure directly) and canvas API
  • Chris was formerly a program manager for the Visual Basic and C# experience in Visual Studio at Microsoft
  • Counterclockwise, the Clojure plugin for Eclipse
  • Support for Clojure in TextMate via textmate-clojure
  • clojure-jack-in, the newest (simpler) entry point for swank-clojure
  • Leiningen and cake have merged forces
  • cljs-watch, a ClojureScript directory watcher
  • Clojure/West


Last episode, I put the call out for people to send in Overtone-produced sounds to serve as intro and outro pieces.  Here’s some info on the clips used in this episode.


Jen Smith coded up bell sounds from scratch using Overtone’s sine-wave ugens, and then composed them to produce a rendition of Troika, the fourth movement of Lieutenant Kije by Sergei Prokofiev.  The code itself ended up being added as an example in the core Overtone repo, and was discussed at some length on the Overtone mailing list here.

(Note: when I recorded the results of Jen’s code, I used a bell metronome with a beat of 250; perhaps that’s not “correct”, but it suited my personal taste for the tune. 🙂


Produced by Damion Junk, the intro was part of a longer track generated by a bracketed L-system, which is “a variant of a formal grammar, most famously used to model the growth processes of plant development”.  Damion used a library he wrote for working with L-systems to produce generated data for Overtone.  Here’s the source for the specific L-system he used for the intro track:

(def descending-moon {:v "RN+-<>[]"
                      :omega ">>>[-----N][++N][++++++N][<<<NR]"
                      :productions {\N "RN++NN----N"
                                    \R "RR"
                                    \> ">"
                                    \< "<"
                                    \+ "+"
                                    \- "-"
                                    \[ "["
                                    \] "]"}})

Episode 0.0.2: Sam Aaron and Overtone at Clojure Conj 2011

Recorded November 12th, 2011, first in a series of conversations from Clojure Conj 2011.

I had the great pleasure of hanging out with Sam Aaron both before and after his presentation at the Conj.  In that presentation, he delivered a brief survey of the history and state of affairs in computer music and an overview of Overtone — an “open source audio environment” built with Clojure — with live, interactive musical performances interspersed throughout to demonstrate some of its capabilities.

This was the last talk of the Conj, and Sam and I recorded this very shortly afterwards.  I don’t know if the organizers were being purposeful about it, but that positioning was brilliant: I (and, I suspect, many others) were so completely blown away by what Sam and the rest of the Overtone team had achieved and by his palpable, absolutely riveting delivery and performance, that I’m not sure the conference could have carried on effectively had he been scheduled midway through.  The reaction of the crowd was jubilant throughout, helping Sam off the stage with a rousing standing ovation of the sort that you hear more often in concert halls and theatres and ballparks than at technical conferences.

For my part, I was stunned.  Totally beyond the cerebral appreciation for the application of Clojure and its powers of abstraction to a domain like music (something that many programmers likely view as “untouchable” in various ways), I always love seeing someone so clearly consumed with passion for their craft.  The sight is inspiring and humbling and I was on a high for the rest of the night.

So, if I sound more enthused than usual through the course of my conversation with Sam…that’s why. 🙂

We talked a bit about his explorations with producing music using Ruby, his path to helping to combine Clojure and SuperCollider into Overtone, the connections between programming, musicality, creativity, and fearlessness, and what he has in mind to help us all make some music, have some fun doing it, and help our friends do the same.

“Sam, you’re badass!”

— Rich Hickey, after Sam’s Overtone presentation


Or, download the mp3 directly.

(Note: while we were recording, we had a number of people stumble into the room we were recording in, so there are some hard stops and odd audio transitions here and there each time we restarted.)

Discrete topics mentioned:

Source code for this episode’s bumpers, produced by Sam Aaron in Overtone: