lazy summer
Originally uploaded by pixietart

I wrote a tiny and very handy JMS drainer in JRuby with Spring at work, but I got fed up with running it from a command line because I am lazy.

So I wanted a web interface to run a drainer in background. Since I got JRuby on Rails in Tomcat running, I checked out BackgroundDRb only briefly, or not harder enough to get it working. To be honest, I could not figure out how I run a JRuby script as task.

Anyway, I came up with a better and simpler solution. I don’t need a fully featured background tasks management for this. I don’t need to persist tasks nor schedule tasks. I don’t care if tasks were terminated in the middle. The only things I need are:

  • Run a task from a web form
  • Show running tasks

I played with JSON and Jetty in JRuby before and found that combination very easy to develop. I have also learnt jQuery to work with JSON at client side recently. So I have used them to implement the above the followings.

  • Make a standalone JRuby task class runnable in a Java thread
  • A servlet in Jetty in JRuby with POST to execute a task in a thread and store the task instance in a global array and GET to return a list of running tasks of their status in JSON.
  • A default servlet in Jetty in JRuby to serve static content, i.e. one HTML page with css, javascripts and images
  • Use jQuery Ajax to load a JSON from the local servlet and populate the task list table dynamically.

That is simple and works well. It scales, too. 20-odd JMS drainers can run in one JVM. The execution is faster and save loads on the server.

I might post sample codes here if anyone is interested in.

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