XAPI Host Plugins

The XenAPI has an extension mechanism that allows one to install a Python script (usually, but it can be any executable) on the host side, and then call that through the XenAPI.” - http://wiki.openstack.org/XenAPI
Writing a XenAPI plugin in Python is simplified by using the XenAPIPlugin module, which is by default installed in dom0 in XCP. Below is a simple XenAPI plugin which reverses a string passed to it:

#!/usr/bin/pythonimport XenAPIPlugindef main(session, args):    try:        data = args["data"]        return data[::-1]    except KeyError:        raise RuntimeError("No argument found with key 'data'.")if __name__ == "__main__":    XenAPIPlugin.dispatch({"main": main})

Save this code to /etc/xapi.d/plugins/reverse and make it executable. The plugin can then be run from the CLI like so:

# xe host-call-plugin host-uuid=<host-uuid> plugin=reverse fn=main args:data="hello, world"

dlrow ,olleh