Icing

Icing

Icing is a way to automatically load the external dependencies for a .clj file before running it. It is the Clojure equivalent to Groovy's Grape.

Example

 (ns
    ^{:project {:dependencies [[clojure "1.2.0"]
                               [hiccup "0.3.0"]]
                :entry lorem}}
  example
  (:use hiccup.core))

(defn lorem
  [args]
  (println (html [:span {:class "lorem"} "ipsom"])))

Running cake icing example.clj will run the given file and entry function with it's meta data dependencies loaded into a new temporary class loader. These dependencies are resolved via Ivy, and downloaded if they are not already in the ivy cache. Dependencies are not copied to a local lib directory; they are used directly from the cache. The persistent Cake JVM is used so it is very fast if the dependencies are already cached and dynamic revisions aren't being used.

 ,-[lrenn@cygnus]-[~/src/icing]-[0]-[9135]
 `-[:)] % time cake icing example.clj
     [icing] :: loading settings :: url = jar:file:/home/lrenn/src/cake/lib/ivy-2.2.0.jar!/org/apache/ivy/core/settings/ivysettings.xml
     [icing] :: resolving dependencies :: icing#icing;0.0.1-SNAPSHOT
     [icing] 	confs: [master, default, devel]
     [icing] 	found org.clojure#clojure;1.2.0 in public
     [icing] 	found hiccup#hiccup;0.3.0 in clojars
     [icing] 	found org.clojure#clojure-contrib;1.2.0 in clojure
     [icing] :: resolution report :: resolve 66ms :: artifacts dl 4ms
 	---------------------------------------------------------------------
 	|                  |            modules            ||   artifacts   |
 	|       conf       | number| search|dwnlded|evicted|| number|dwnlded|
 	---------------------------------------------------------------------
 	|      master      |   0   |   0   |   0   |   0   ||   0   |   0   |
 	|      default     |   3   |   0   |   0   |   0   ||   3   |   0   |
 	|       devel      |   0   |   0   |   0   |   0   ||   0   |   0   |
 	---------------------------------------------------------------------
 <span class="lorem">ipsom</span>
 cake icing example.clj  0.10s user 0.01s system 40% cpu 0.269 total

Testing Icing

The icing target is currently on Cake's Ivy branch. Follow the directions for Testing Ivy Support on the Ivy wiki page. Your entry function must take a single parameter. Currently only "" is passed, but command line arguments will eventually be passed. It should not be run in a project directory. I need to pin it to the global project.

TODO

• Even though entry must take a single parameter, I'm not passing the command line arguments for it.
• It would be nice if you could pass system properties.
• Ensure it's always run in the global project.
• Come up with a better name, syntax for meta data keys.