Creating an extension

An rspec extension is typically created in RelaxNG Compact (rnc) format. This format is then "compiled" into an XML Schema (xsd file).

Here is an rnc file for the post-boot script extension (comments removed):

default namespace = "http://www.geni.net/resources/rspec/ext/postBootScript/1"

Services =
  element services_post_boot_script { PostBootScriptContents }

PostBootScriptContents =
  attribute type { text } &
  text

start = Services

Now, run [trang](http://www.thaiopensource.com/relaxng/trang-manual.html) to translate the rnc file to an xsd file:

java -jar trang.jar request.rnc request.xsd

These files (request.rnc, request.xsd) live in an emulab-hosted git repository (git-public.flux.utah.edu:/git/geni-rspec.git). See http://users.emulab.net/trac/emulab/wiki/GITWorkflow for info.

There’s more to the story, but these are the basics.