Jenkins Job DSL - can't load parmeters from file

Question

DSL job:

#!groovy

def file = readFileFromWorkspace('params.properties').trim()


job('app-adm') {
  label("adm")
  println("#" + file + "#")
  parameters{
    file 
  }
  steps 
  {
    shell(readFileFromWorkspace('script-adm.sh'))
  }
}

job('app-tst-mt')
{
  parameters 
  {
     booleanParam('FLAG', true)
  }
  steps 
  {
    shell(readFileFromWorkspace('script-tst-mt.sh'))
  }
}

params.properties:

choiceParam('OPTION', ['option 1 (default)', 'option 2', 'option 3'])

I've tried:

• Use files as input to Jenkins JobDSL
• adding through single variable like x=<param> and parameteres { x }
• different formats

Nothing is working, through println inside job, I can clearly see that there is string that I want to put in parameters, but when doing so it dosen't register it and I don't get any params.