scripting

Recently I wanted to demo how to do something in RHQ’s CLI. It was a fairly simple thing but our API being what it is, built for and implemented in Java, the result ended up being kinda verbose and didn’t exactly look like your modern fluent Javascript code.

RHQ 4.5.0 (which we released today) contains a great deal of scripting enhancements that I think are worth talking about in more detail. In my eyes, the changes make the scripting in RHQ ready for serious use.

In the past few weeks I was quite busy refactoring RHQ’s CLI and scripting integration. Funnily enough it all started because we wanted to add the support for CommonJS modules to our javascript interface. During the course of the refactoring, I found out that I’m actually heading in the direction of completely separating the "language" support from the rest of the RHQ, which then only speaks to it through the Java’s standard scripting APIs which are language independent.

In RHQ we let the users provide scripts that can be run when an alert fires. This is great for automation because the script can do anything the users can do with our remote API. But the users of course can write a script like this:

I watched the great demo of the XMPP server plugin for RHQ from Rafael Chies. Rafael is using a custom DSL to query the RHQ server for information but I thought that that really shouldn’t be necessary - it should be possible to use an ordinary CLI session behind this. Granted - the "query language" of our remote API is more complicated than the simple DSL Rafael is using but at the same time, the API we use in the CLI is much more feature rich and I wouldn’t have to reimplement any of it if I was able to "blend" the CLI session with the XMPP chat.