The Hand That Rocks The Gradle

A few more month passed, and much has happened in the clojure scene. Clojure 1.1.0 was released in 2009-12. The clojure plugin clj-gradle has been renamed to clojuresque and updated to 1.3. Clojars.org, which is a community repo of clojure libraries accessable via mvn and ivy is online. I’ve done some clojure talks, added a few people to my clojure army.

But it means my previous two posts on clojure and gradle are very outdated. So I figure it’s time to share my current clojure and gradle setup. It’s much more simple now. The only thing you are required to do before following this, is to have gradle 0.8 setup. That’s it.

First you need to setup a sandbox directory. Inside the directory, you want to create a file build.gradle
Here is what I use.

buildscript {
  repositories {
    mavenRepo name: 'clojars', urls: 'http://clojars.org/repo'
  }
  dependencies {
    classpath 'clojuresque:clojuresque:1.3.0'
  }
}

usePlugin(clojuresque.ClojurePlugin)

group = 'yourgrouphere'
version = '1.0.0'

warnOnReflection = true
aotCompile = true

clojureSnapshotsRepo(repositories)
clojarsRepo(repositories)
gradleHomeRepo(repositories)

repositories {
  mavenCentral()
  mavenRepo urls: "http://build.clojure.org/releases"
}

dependencies {
  compile 'org.clojure:clojure:1.2.0-master-SNAPSHOT'
  compile 'org.clojure:clojure-contrib:1.2.0-master-SNAPSHOT'
  compile 'enlive:enlive:1.0.0-SNAPSHOT'
  compile 'org.ccil.cowan.tagsoup:tagsoup:1.2'
//  compile 'org.clojure:clojure:1.1.0'
//  compile 'org.clojure:clojure-contrib:1.1.0'
}

configureClojarsDeploy(uploadArchives)

task initProject(description: 'Initialize project directory structure.') << {
  ['clojure'].each {
  convention.sourceSets.all*."${it}".srcDirs*.each { it.mkdirs() }
  }
}

task copyToLib(dependsOn: configurations.default.buildArtifacts, type: Copy) {
  into('build/lib')
  from configurations.default
  from configurations.default.allArtifacts*.file
}

It has a couple of helpful targets. The initProject setup the src subdirectories for you. If you have groovy and java code, you can of course append to that. The copyToLib target will copy all the jars into build/lib.

The script also set up clojars.org repo for you. In fact, it pulls clojuresque from it. I also enable mvn central repo, as well as the build.clojure.org repo to pull either release or nightly snapshot version of the clojure and clojure-contrib.

I also went ahead and added enlive to the dependencies to show you how to add dependencies from clojars.org. No, it’s not a typo. It really is enlive:enlive:1.0.0-SNAPSHOT. Beacuse in clojars.org, the name of the project is used in both group and artifact id. It doesn’t follow the java convention. The tagsoup dependency is because of enlive. That one is from mvn repo and does follow the java convention.

You’ll see I have the 1.1.0 release for clojure and clojure-contrib commented out. It’s very important you use matching clojure and clojure-contrib version. I tend to do my development using the bleeding edge version. But if you want to swtich back to release. It’s as easy as comment out the two 1.2.0 entries, and uncomment the two 1.1.0 entries.

Now, let’s create src/main/clojure/mystuff/example.clj

(ns mystuff.example
    (:use net.cgrand.enlive-html)
    (:import java.net.URL)
    (:gen-class))

  (defn -main []
      (println (-> "http://www.penny-arcade.com/comic/" URL. html-resource
                     (select [:.body :img]) first :attrs :src)))

Then issue “gradle build”. If all goes well, you will get a build successful. Now issue “gradle copyToLib”. All the jars will be copied to build/lib. I named my sandbox directory blogtest. So I have a blogtest-1.0.0.jar.

Time to see the url of the latest comic.

java -cp ./clojure-1.2.0-master-SNAPSHOT.jar:./clojure-contrib-1.2.0-master-SNAPSHOT.jar:./enlive-1.0.0-SNAPSHOT.jar:./tagsoup-1.2.jar:./blogtest-1.0.0.jar mystuff.example
http://art.penny-arcade.com/photos/807260572_n6CMU-L.jpg

Well, that worked, even if the comic isn’t very funny today. Yes, you can in fact use wildcard for classpath if you want.