Error occurs when stop the heat-engine.service

Hi,

In the ocata and pike version of heat on ubuntu 16.04, the stop of heat-engine service will trigger the error.

2017-10-09 17:40:58.960 26236 DEBUG heat.engine.service [-] Attempting to stop engine service... _stop_rpc_server /usr/lib/python2.7/dist-packages/heat/engine/service.py:425
2017-10-09 17:40:58.961 26237 DEBUG heat.engine.service [-] Attempting to stop engine service... _stop_rpc_server /usr/lib/python2.7/dist-packages/heat/engine/service.py:425
2017-10-09 17:40:58.963 26239 DEBUG heat.engine.service [-] Attempting to stop engine service... _stop_rpc_server /usr/lib/python2.7/dist-packages/heat/engine/service.py:425
2017-10-09 17:40:58.964 26238 DEBUG heat.engine.service [-] Attempting to stop engine service... _stop_rpc_server /usr/lib/python2.7/dist-packages/heat/engine/service.py:425
2017-10-09 17:40:58.975 26219 INFO oslo_service.service [-] Caught SIGTERM, stopping children
2017-10-09 17:40:58.975 26219 DEBUG oslo_concurrency.lockutils [-] Acquired semaphore "singleton_lock" lock /usr/lib/python2.7/dist-packages/oslo_concurrency/lockutils.py:215
2017-10-09 17:40:58.976 26219 DEBUG oslo_concurrency.lockutils [-] Releasing semaphore "singleton_lock" lock /usr/lib/python2.7/dist-packages/oslo_concurrency/lockutils.py:228
2017-10-09 17:40:58.976 26219 DEBUG oslo_service.service [-] Stop services. stop /usr/lib/python2.7/dist-packages/oslo_service/service.py:624
2017-10-09 17:40:58.980 26219 CRITICAL heat-engine [req-915752c5-51a0-4cc8-a51e-54e3ab533286 - - - - -] Unhandled error: TypeError: object of type 'NoneType' has no len()
2017-10-09 17:40:58.980 26219 ERROR heat-engine Traceback (most recent call last):
2017-10-09 17:40:58.980 26219 ERROR heat-engine File "/usr/bin/heat-engine", line 10, in <module>
2017-10-09 17:40:58.980 26219 ERROR heat-engine sys.exit(main())
2017-10-09 17:40:58.980 26219 ERROR heat-engine File "/usr/lib/python2.7/dist-packages/heat/cmd/engine.py", line 86, in main
2017-10-09 17:40:58.980 26219 ERROR heat-engine launcher.wait()
2017-10-09 17:40:58.980 26219 ERROR heat-engine File "/usr/lib/python2.7/dist-packages/oslo_service/service.py", line 618, in wait
2017-10-09 17:40:58.980 26219 ERROR heat-engine self.stop()
2017-10-09 17:40:58.980 26219 ERROR heat-engine File "/usr/lib/python2.7/dist-packages/oslo_service/service.py", line 628, in stop
2017-10-09 17:40:58.980 26219 ERROR heat-engine service.stop()
2017-10-09 17:40:58.980 26219 ERROR heat-engine File "/usr/lib/python2.7/dist-packages/osprofiler/profiler.py", line 153, in wrapper
2017-10-09 17:40:58.980 26219 ERROR heat-engine return f(*args, **kwargs)
2017-10-09 17:40:58.980 26219 ERROR heat-engine File "/usr/lib/python2.7/dist-packages/heat/engine/service.py", line 457, in stop
2017-10-09 17:40:58.980 26219 ERROR heat-engine service_objects.Service.delete(ctxt, self.service_id)
2017-10-09 17:40:58.980 26219 ERROR heat-engine File "/usr/lib/python2.7/dist-packages/heat/objects/service.py", line 77, in delete
2017-10-09 17:40:58.980 26219 ERROR heat-engine db_api.service_delete(context, service_id, soft_delete)
2017-10-09 17:40:58.980 26219 ERROR heat-engine File "/usr/lib/python2.7/dist-packages/heat/db/sqlalchemy/api.py", line 1256, in service_delete
2017-10-09 17:40:58.980 26219 ERROR heat-engine service = service_get(context, service_id)
2017-10-09 17:40:58.980 26219 ERROR heat-engine File "/usr/lib/python2.7/dist-packages/heat/db/sqlalchemy/api.py", line 1266, in service_get
2017-10-09 17:40:58.980 26219 ERROR heat-engine result = context.session.query(models.Service).get(service_id)
2017-10-09 17:40:58.980 26219 ERROR heat-engine File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 864, in get
2017-10-09 17:40:58.980 26219 ERROR heat-engine return self._get_impl(ident, loading.load_on_ident)
2017-10-09 17:40:58.980 26219 ERROR heat-engine File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 875, in _get_impl
2017-10-09 17:40:58.980 26219 ERROR heat-engine if len(ident) != len(mapper.primary_key):
2017-10-09 17:40:58.980 26219 ERROR heat-engine TypeError: object of type 'NoneType' has no len()
2017-10-09 17:40:58.980 26219 ERROR heat-engine
2017-10-09 17:40:59.077 26239 INFO oslo_service.service [-] Parent process has died unexpectedly, exiting
2017-10-09 17:40:59.078 26238 INFO oslo_service.service [-] Parent process has died unexpectedly, exiting
2017-10-09 17:40:59.078 26236 INFO oslo_service.service [-] Parent process has died unexpectedly, exiting
2017-10-09 17:40:59.078 26237 INFO oslo_service.service [-] Parent process has died unexpectedly, exiting
2017-10-09 17:40:59.079 26236 DEBUG heat.engine.service [-] Attempting to stop engine service... _stop_rpc_server /usr/lib/python2.7/dist-packages/heat/engine/service.py:425
2017-10-09 17:40:59.079 26237 DEBUG heat.engine.service [-] Attempting to stop engine service... _stop_rpc_server /usr/lib/python2.7/dist-packages/heat/engine/service.py:425
2017-10-09 17:40:59.079 26238 DEBUG heat.engine.service [-] Attempting to stop engine service... _stop_rpc_server /usr/lib/python2.7/dist-packages/heat/engine/service.py:425
2017-10-09 17:40:59.082 26239 DEBUG heat.engine.service [-] Attempting to stop engine service... _stop_rpc_server /usr/lib/python2.7/dist-packages/heat/engine/service.py:425

Using "systemctl stop heat-engine.service" will trigger the error.

It looks like the EngineService object(self) will be initialized again after the _stop_rpc_server() function. Therefore the services delete cannot be performed due to self.service_id is none.

Besides the error, there is no other side effect for the service stop issue. Heat engine service could be started well and running without problems.