This document is about generic scripting. This does not only mean to excecute scripts as operations like we currently have, but to be able to run scripts in order to Facet-work

In the current (RHQ 1.1) situation all metadata is stored in the plugin descriptor.

If a metric is numeric or a trait is stored in the descriptor. What unit is has as well.

If the plugin could execute a script that returns a value on stdout:

#!/bin/sh

echo 1

If the plugin would want to use this script it would need to know the return type of the script – and it would only be able to use one return value. Units would probably be none

The proposal is now to add a "MetadataDiscoveryComponent" where the script(s) could the metadata in some form for the agent and server to digest and set up.
We would need to treat this metadata differently from the 'classical' one in a sense that we would need some more strict validation and also provide the possibility to delete it (along with gathered data) from the admin gui.

A 2nd script would then do the resource discovery as in the discovery component and a 3rd one as shown above would implement the MeasurementFacet. The same goes for OperationFacet and perhaps even ConfigurationFacet.