foo.rb

Rules = {
  enter: [ 'created' ],
  exit: [ 'completed' ],
  uncancelable: %w[ completing completed ],
  tasks: [
      { 
        name: 'tag',
        desc: 'taggable',
        transitions: [
          { from: { state: 'tagging', :status: 'pending' }, to: { state: 'tagged' } },
          { from: { state: 'tagging', :status: 'pending' }, to: { state: 'tagged' status: 'aborted' } },
        ]
      },
      { 
        name: 'complete',
        desc: 'completable',
        transitions: [
          { from: { state: 'completing',   :status: 'pending'   }, to: { state: 'completed', status: 'succeeded' } },
          { from: { state: 'completing',   :status: 'canceling' }, to: { state: 'completed', status: 'canceled'  } },
          { from: { state: 'completing',   :status: 'aborting'  }, to: { state: 'completed', status: 'aborted'   } },
        ]
      }
  ]
 
  transitions: [
    # pending
    { retriable: true, from: { state: 'created', status: 'pending' }, to: { state: 'tagging'    } }
    { retriable: true, from: { state: 'tagged',  status: 'pending' }, to: { state: 'scheduling' } }
    # canceling
    { from: { state: 'created', status: 'canceling' }, to: { state: 'completing' } }
    { from: { state: 'tagged',  status: 'canceling' }, to: { state: 'completing' } }
    # aborting
    { from: { state: 'tagged',  status: 'aborting' }, to: { state: 'completing' } }
  ] 
}

foo.yaml

---
enter:
  - created
exit:
  - completed
cancelable:
  - created
  - tagging
  - tagged
tasks:
  - name: tag
    desc: taggable
    transitions:
      - from:
          state: tagging
          status: pending
        to:
          state: tagged
          
          
  - name: complete
    desc: completable
    transitions:
      - from:
          state: completing
          status: pending
        to:
          state: completed
          status: succeeded
      - from:
          state: completing
          status: canceling
        to:
          state: completed
          status: canceled
      - from:
          state: completing
          status: aborting
        to:
          state: completed
          status: aborted
          
transitions:
  - retriable: true
    from:
      state: created
      status: pending
    to:
      state: tagging
  - retriable: true
    from:
      state: tagged
      status: pending
    to:
      state: scheduling
  - from:
      state: tagged
      status: canceling
    to:
      state: completing
  - from:
      state: tagged
      status: aborting
    to:
      state: completing