Pymongo raises exception when no flows are provided - pymongo.errors.InvalidOperation: No operations to execute

[italovalcy]

Hi,

Accidently I send a KytosEvent to install flows to FlowManager with an empty list of flows, and the following error was raised:

2022-08-10 12:34:29,990 - INFO [kytos.napps.kytos/flow_manager] [main.py:487:handle_flows_install_delete] (thread_pool_app_337) Send FlowMod from KytosEvent dpid: 00:00:00:00:00:00:00:16, command: add, force: False, flows_dict: {'flows': []}
2022-08-10 12:34:29,991 - INFO [kytos.napps.kytos/flow_manager] [main.py:487:handle_flows_install_delete] (thread_pool_app_37) Send FlowMod from KytosEvent dpid: 00:00:00:00:00:00:00:21, command: add, force: False, flows_dict: {'flows': []}
2022-08-10 12:34:30,017 - ERROR [kytos.core.helpers] [helpers.py:151:handler_context_apm] (thread_pool_app_37) listen_to handler: <function Main.on_flows_install_delete at 0x7fad60304b80>, args: (<Main(flow_manager, stopped 140380066543360)>, KytosEvent('kytos.flow_manager.flows.install', {'dpid': '00:00:00:00:00:00:00:21', 'flow_dict': {'flows': []}, 'log_info': 'mef_eline.handle_link_down'}, 0)) traceback: Traceback (most recent call last):,   File "/usr/local/lib/python3.9/dist-packages/kytos/core/helpers.py", line 146, in handler_context_apm,     result = handler(*args),   File "//var/lib/kytos/napps/kytos/flow_manager/main.py", line 466, in on_flows_install_delete,     self.handle_flows_install_delete(event),   File "//var/lib/kytos/napps/kytos/flow_manager/main.py", line 492, in handle_flows_install_delete,     self._install_flows(command, flow_dict, [switch], reraise_conn=not force),   File "//var/lib/kytos/napps/kytos/flow_manager/main.py", line 608, in _install_flows,     self.flow_controller.upsert_flows(,   File "/usr/local/lib/python3.9/dist-packages/tenacity/__init__.py", line 324, in wrapped_f,     return self(f, *args, **kw),   File "/usr/local/lib/python3.9/dist-packages/tenacity/__init__.py", line 404, in __call__,     do = self.iter(retry_state=retry_state),   File "/usr/local/lib/python3.9/dist-packages/tenacity/__init__.py", line 349, in iter,     return fut.result(),   File "/usr/lib/python3.9/concurrent/futures/_base.py", line 433, in result,     return self.__get_result(),   File "/usr/lib/python3.9/concurrent/futures/_base.py", line 389, in __get_result,     raise self._exception,   File "/usr/local/lib/python3.9/dist-packages/tenacity/__init__.py", line 407, in __call__,     result = fn(*args, **kwargs),   File "/usr/local/lib/python3.9/dist-packages/kytos/core/retry.py", line 25, in decorated,     return func(*args, **kwargs),   File "//var/lib/kytos/napps/../napps/kytos/flow_manager/controllers/__init__.py", line 93, in upsert_flows,     return self.db.flows.bulk_write(ops).upserted_ids,   File "/usr/local/lib/python3.9/dist-packages/elasticapm/instrumentation/packages/base.py", line 210, in call_if_sampling,     return self.call(module, method, wrapped, instance, args, kwargs),   File "/usr/local/lib/python3.9/dist-packages/elasticapm/instrumentation/packages/pymongo.py", line 94, in call,     return wrapped(*args, **kwargs),   File "/usr/local/lib/python3.9/dist-packages/pymongo/collection.py", line 514, in bulk_write,     bulk_api_result = blk.execute(write_concern, session),   File "/usr/local/lib/python3.9/dist-packages/pymongo/bulk.py", line 495, in execute,     raise InvalidOperation("No operations to execute"), pymongo.errors.InvalidOperation: No operations to execute,

I believe this is an improvement opportunity for us.

The original error was send the empty list of flows (which I've already fixed on my scenario).

[viniarck]

@italovalcy, for sure, and thanks for reporting this.

We've got this issue #73 to handle error in this listen_to handler, I suppose we can follow a similar approach refining the errors and follow an equivalent pattern that it's being used for kytos/flow_manager.flow.error, and ideally compatible to evolve to reuse rexisting validation functionality. If currently, mef_eline can avoid hitting those validation errors then I believe we should be able to prioritize this in a next opportunity, let me know.