Python DateTime Error For Job Events In Event Grid Azure Function

[mykidlucifer]

Issue Description

The Azure Event Grid Trigger function in python throws an error on receiving a job event(Azure Media Services). The error is related to DateTime format. The date returned by the job event to the python function cannot be parsed by python. E.g. the eventTime: '2019-12-06T07:41:37.3847161' cannot be parsed by python.

Result: Failure
Exception: ValueError: time data '2019-12-06T07:41:37.3847161' does not match format '%Y-%m-%dT%H:%M:%S.%fZ'
Stack: File "/azure-functions-host/workers/python/3.7/LINUX/X64/azure_functions_worker/dispatcher.py", line 297, in _handle__invocation_request
pytype=pb_type_info.pytype)
File "/azure-functions-host/workers/python/3.7/LINUX/X64/azure_functions_worker/bindings/meta.py", line 63, in from_incoming_proto
return binding.decode(datum, trigger_metadata=metadata)
File "/azure-functions-host/workers/python/3.7/LINUX/X64/azure/functions/eventgrid.py", line 35, in decode
event_time=cls._parse_datetime(body.get('eventTime')),
File "/azure-functions-host/workers/python/3.7/LINUX/X64/azure/functions/meta.py", line 209, in _parse_datetime
raise last_error
File "/azure-functions-host/workers/python/3.7/LINUX/X64/azure/functions/meta.py", line 204, in _parse_datetime
dt = datetime.datetime.strptime(datetime_str, fmt)
File "/usr/local/lib/python3.7/_strptime.py", line 577, in _strptime_datetime
tt, fraction, gmtoff_fraction = _strptime(data_string, format)
File "/usr/local/lib/python3.7/_strptime.py", line 359, in _strptime
(data_string, format))

In my case: eventTime of job event don't have a character 'Z' in last variable: '2019-12-06T07:41:37.3847161'. I test with local and add 'Z' at last eventTime variable: ' '2019-12-06T07:41:37.3847161Z'. The function will run Success.
How I can config eventTime format is correct or any way to workarounds with that eventTime of job event.

[Hazhzeng]

I just confirmed that only the media service EventGrid event schema provides a local time without timezone information which does not match the ISO 8601 format
https://docs.microsoft.com/en-us/azure/media-services/latest/media-services-event-schemas?toc=%2fazure%2fevent-grid%2ftoc.json

The error is caused by the Python worker attempts to convert the eventtime string into Python's datetime using ISO 8601 parser.
In Node worker, the binding does not attempt to validate the format and no conversion is performed. The eventtime is propagated to customer's code as string.

My proposal for the fix is to use localtime parser (datetime.strptime) when the timezone information is not provided.