code: def _do_customer_service(self):
          
          if self.customer_service_dir is None: return
          doit = self.exceptions or not self.flow.all_ok
          doit = True
          if not doit: return
  
          prefix = os.path.basename(self.flow.workdir) + "_"
  
          import tempfile, datetime
          suffix = str(datetime.datetime.now()).replace(" ", "-")
          # Remove milliseconds
          i = suffix.index(".")
          if i != -1: suffix = suffix[:i]
          suffix += ".tar.gz"
  
          #back = os.getcwd()
          #os.chdir(self.customer_service_dir.path)
  
          _, tmpname = tempfile.mkstemp(suffix="_" + suffix, prefix=prefix,
                                        dir=self.customer_service_dir.path, text=False)
  
          print("Dear customer,\n We are about to generate a tarball in\n  %s" % tmpname)
          self.flow.make_light_tarfile(name=tmpname)
docs: This method is called before the shutdown of the scheduler.
          If customer_service is on and the flow didn't completed successfully,
          a lightweight tarball file with inputs and the most important output files
          is created in customer_servide_dir.