Can I use script from jenkins shared library to load options to Active Choices parameter?

Question

Can I use script from jenkins shared library to load options from .json file? I have script in /vars dir which is used to return entries from json file. This is my parameters section:

            parameters([
                    [$class: 'CascadeChoiceParameter',
                     choiceType: 'PT_MULTI_SELECT',
                     description: 'Select machines',
                     filterLength: 1,
                     filterable: true,
                     name: 'machineNames',
                     referencedParameters: '',
                     script: [$class: 'GroovyScript',
                              fallbackScript: [
                                      classpath: [],
                                      sandbox: false,
                                      script: 'return ["Please select a deliverable first"]'
                              ],
                              script: [
                                      classpath: [],
                                      sandbox: false,
                                      script: 'return loadMachineList()'
                              ]
                     ]
                    ],
...

loadMachineList() function is returning list of machines separated with coma. Function itself it is working, I verified it in build.

When I try to run job ("build with parameters") there are any options to choose from.

I verified the script itself - it works. I tried to call script as loadMachineList(), vars/loadMachinesList() but without result.

Answer 1

I'm afraid no, AFAIK the script has to be inline and you can't load the script from external sources. One workaround is to add your script into a custom Jar and point to the custom Jar in classpath[] section. Apart from that, whatever you put in the Script section within the Properties block must be self-contained.