code: def get_component_list_from_workers(self, worker_metadatas):
          
          comp_list = []
          for platform in sorted(worker_metadatas.keys()):
              for instance in worker_metadatas[platform]['output']:
                  if instance['type'] == 'docker-image':
                      if 'components' not in instance or not instance['components']:
                          self.log.warn("Missing 'components' key in 'output' metadata instance: %s",
                                        instance)
                          continue
  
                      comp_list.append(instance['components'])
  
          return comp_list
docs: Find the component lists from each worker build.
  
          The components that are interesting are under the 'output' key.  The
          buildhost's components are ignored.
  
          Inside the 'output' key are various 'instances'.  The only 'instance'
          with a 'component list' is the 'docker-image' instance.  The 'log'
          instances are ignored for now.
  
          Reference plugin post_koji_upload for details on how this is created.
  
          :return: list of component lists