Skip to main content
DevOps Image

This post is from the XebiaLabs blog and has not been updated since the original publish date.

Last Updated Jan 12, 2015 — DevOps Expert

Compute Property Values With Rules


A quick tip I used to help a customer. They've defined 2 extra properties on their host to help them to compute container's properties (eg home). It works fine for the generic-plugin based middleware (eg tomcat.home="${}/var/wildfly/${container.instanceId}") but not for other plugins based not based on the generic plugin. My first answer was to create a cli script that performs the computation and update the configuration items according to the expected definition but the Ops team needs to switch to another tools. My next answer was to define a control task that can called from the UI but typically the 'repositoryService' is not injected in the script's context: impossible to update the configuration item's values. So I found out the following solution: define a rule that perform the computation using a pre-plan processor and a python script:

<rule name="compute.jboss.home.context" scope="pre-plan">
And the python script 'compute/' is :
def jboss_containers():
    return filter(lambda ci: str(ci.type) == 'jbossdm.StandaloneServer', deployedApplication.environment.members)
for container in jboss_containers():
    if not container.home.startswith('/'):
        print "---- processing %s " % container
        print "processing host %s " %
        home = "%s/var/wildfly/wf-%s" % (,
        container.home = home
        repositoryService.update(, container)
The main advantage: no need to think to trigger any extra commands or control tasks: the computation is performed during the planning phase executed when XLDeploy generates the deployment tasks.xl-rules rulez !!!

More from the Blog

View more
Jun 10, 2021

Desilo DevOps: The power of bringing all your tools and data into one view

When discussing value stream management (VSM), our resources talk a lo ...
Read More
Jun 07, 2021

"How do I get started?" Key steps to improving your end-to-end DevOps process

There is an extraordinary variety of DevOps solutions available on the ...
Read More
May 24, 2021

Integrate your DevOps toolchain, simplify your life

Organizations can view the entirety of the tools and platforms they us ...
Read More
May 17, 2021

Why Companies in Competitive Industries Adjusted Better During COVID-19

As we continue to assess the dramatic effects of the global COVID-19 p ...
Read More
Contact Us