server crash if header grpc-accept-encoding is missing

[truhlik]

If client does not send header "grpc-accept-encoding" then the server crash. Bellow is stacktrace:

�[36mmailing_1  |�[0m   File "/usr/local/lib/python3.7/site-packages/eventlet/greenthread.py", line 181, in wait
�[36mmailing_1  |�[0m     return self._exit_event.wait()
�[36mmailing_1  |�[0m   File "/usr/local/lib/python3.7/site-packages/eventlet/event.py", line 132, in wait
�[36mmailing_1  |�[0m     current.throw(*self._exc)
�[36mmailing_1  |�[0m   File "/usr/local/lib/python3.7/site-packages/eventlet/greenthread.py", line 221, in main
�[36mmailing_1  |�[0m     result = function(*args, **kwargs)
�[36mmailing_1  |�[0m   File "/usr/local/lib/python3.7/site-packages/nameko_grpc/connection.py", line 76, in run_forever
�[36mmailing_1  |�[0m     self.request_received(event)
�[36mmailing_1  |�[0m   File "/usr/local/lib/python3.7/site-packages/nameko_grpc/entrypoint.py", line 56, in request_received
�[36mmailing_1  |�[0m     request_stream.headers.get("grpc-encoding"),
�[36mmailing_1  |�[0m   File "/usr/local/lib/python3.7/site-packages/nameko_grpc/compression.py", line 46, in select_algorithm
�[36mmailing_1  |�[0m     if encoding in acceptable_encodings:
�[36mmailing_1  |�[0m TypeError: argument of type 'NoneType' is not iterable

The problem is within this line and is obvious:

nameko-grpc/nameko_grpc/compression.py

Line 46 in 367706c

if encoding in acceptable_encodings:

I can contribute with PR if you would like to.

[mattbennett]

@truhlik sorry for not replying to this sooner!

I guess we should assume identity if the header is missing, although I don't know if omitting the header is allowable according to the spec?

[truhlik]

I am not well familiar with specs, maybe you are right. The fallback, if header is missing, is up to you.
But the main problem is that nameko fail completely if this request (without header) is received.
I would be OK also with some kind of error message if header is missing.

BTW check frepond@188f9e5

Thank you.