Thursday, April 18, 2013

Ganelon 0.9.0 released

Ganelon - a micro-framework supporting server-side oriented AJAX web applications in Ring/Clojure has been released in version 0.9.0 - first publicly available non-SNAPSHOT.

In addition to that, an interactive tutorial app (meetings management with MongoDB) has been launched at Source codes for it can be found in GitHub repository:
In the following weeks, this tutorial app will be used as a base for a tutorial blog series.

Using Ganelon

To use Ganelon in your Compojure/Ring/Clojure web application, simply add the following dependency to your project.clj file:

    [ganelon "0.9.0"]
For more information on using Ganelon, please visit

Production use

Ganelon is used to build user interface for Daily Social - social news aggregator delivering top stories to Pocket or Readability. So it is used in production for almost half a year. The demo and interactive tutorial sites are written using Ganelon as well.

I think that the best thing to do now - is to give a Ganelon a try and see how it works out for yourself.
Any issues/fixes can be reported directly to the GitHub repo at

Most important features

As this is a first major release of Ganelon, instead of changes introduced, I will simply highlight most important features:
  • AJAX support for client-side operations, including basic functions and almost whole jQuery | Manipulation library.
    • Ability to add custom client-side operations.
    • Additional libraries for Bootstrap Modal JavaScript and jquery gritter plugin (Growl-style notifications).
  • Support for definition of AJAX actions as Compojure routes.
  • Basic functions rendering client-side code for HTML/JavaScript controls invoking AJAX actions.
  • Support for distributed configuration of Compojure routes - somewhat akin to Noir's defpage macro.
Helper library for Ganelon - ganelon-util has been released as well - the current version is 0.8.0. Ganelon adds subdependency on ganelon-util, so you don't have to worry about adding it manually.

Thursday, April 11, 2013

Running and debugging Clojure code with Intellij IDEA

In the following blog post, I will show how to install La Clojure plugin, import project from leiningen to IntelliJ IDEA, how to interact with REPL and finally how to use IDEA's debugger to debug Clojure code run from REPL. 
These features make Clojure development with IDEA a real pleasure.

Installation of La Clojure plugin

To use Clojure with IntelliJ IDEA, we have to add La Clojure plugin. To do that, we open File / Settings / Plugins from a menu, than click on Browse repositories... button at the bottom of the Settings window (highlighted in red).

Then, we select La Clojure from plugins list (we can use filter in the right top corner of the window), right click on the item and select Download and Install command:

Upon leaving the Settings window, IDEA will ask if we want to restart it - the plugin will not work unless we do.

Importing leiningen project

With the La Clojure plugin ready and active, we can import a leiningen project into IntelliJ IDEA. All we have to do is to generate appropriate Maven pom.xml file:

lein pom

Then, we can import the maven module using IntelliJ IDEA.

Step 1: select Import Project from welcome screen:

Step 2: point IDEA to pom.xml (not project.clj) file:

After steps above, you can follow standard IntelliJ IDEA Maven project import procedure: confirm Maven project options, select IDE, set project name and IDEA files location for a project.

One thing that has to be done manually is adding Clojure Facet to project modules. To do that, we simply select File / Project structure from a menu, then navigate to our module in Modules tab, click on a + sign and finally select Clojure:

Starting the REPL

With Maven project loaded successfully, IDEA will fetch dependencies which aren't already in Maven local repository. With these libraries fetched, we can start Clojure REPL for our project by selecting Tools / Start Clojure Console from a menu. 

We can also use the keyboard shortcut - Ctrl-Shift-D by default in the newest La Clojure version.

The REPL will set a classpath for all of our libraries and sources referenced in a current module:

Interacting with REPL

To load a current Clojure file to REPL by a load-file function, all we have to do is to select Tools / Clojure REPL / Load file to REPL or use a keyboard shortcut - Ctrl-Shift-L by default.

We can also use Tools / Clojure REPL menu to:
  • Run selected text in REPL 
  • Execute last S-Expression in REPL
  • Run top S-Expression in REPL

Debugging with REPL

With IntelliJ IDEA we can connect a remote debugger to a REPL, allowing us to debug our Clojure code.

Step 1: we have to create a Remote Debugger profile using Run / Edit Configurations... from a menu.
To add a Remote Debugger, we have to click on the plus '+' sign and select 'Remote' configuration type:

We can adjust the settings or leave them as default. Most importantly, we have to copy command line arguments for running remote JVM, for example:


The default value for port is 5005, but it can be adjusted in case there is another process already listening on that port.

It is also convienient to name this Remote Debugging session as 'Clojure REPL Debugger' for example.

Step 2: apply command line arguments to REPL settings for Clojure facet in our module (File / Project Structure / Modules / [our module] / Clojure / JVM arguments):

Step 3: Start a REPL with Tools / Start Clojure Console or a keyboard shortcut - Ctrl-Shift-D by default:

If the REPL is already running, it needs to be stopped and started again.

Step 4: Start Remote Debugger configuration created in step 1 with Run / Debug 'Clojure REPL Debugger' or a keyboard shortcut - Shift-F9 by default.

The name of Remote Debugger configuration is dependent on the configuration created in step 1. For the sake of example, I am using 'Clojure REPL Debugger'.

And finally, with the Remote Debugger ready and connected to REPL, we can debug our Clojure code: