Doesn't report error status in `execute_reply` msg
jayendra13 opened this issue · comments
Version info
matlab : 9.5.0.944444 (R2018b)
matlab_kernel : 0.15.1
I am running a matlab code with matlab_kernel having a syntax error, and tracking the messages from the iopub channel.
This is the execute_reply msg from the iopub channel.
{'buffers': [],
'content': {u'execution_count': 1,
u'payload': [],
u'status': u'ok',
u'user_expressions': {}},
'header': {u'date': datetime.datetime(2018, 10, 4, 6, 11, 22, 642374, tzinfo=tzutc()),
u'msg_id': u'1f698f2d-0d99bf43400c21a4a318708d',
u'msg_type': u'execute_reply',
u'session': u'94bae730-e12ee227be016e5e947bf704',
u'username': u'jayendra',
u'version': u'5.3'},
'metadata': {u'started': u'2018-10-04T06:11:22.406073Z'},
'msg_id': u'1f698f2d-0d99bf43400c21a4a318708d',
'msg_type': u'execute_reply',
'parent_header': {u'date': datetime.datetime(2018, 10, 4, 6, 11, 16, 937573, tzinfo=tzutc()),
u'msg_id': u'e5c2386c-c924e5654ae5e26a59336730',
u'msg_type': u'execute_request',
u'session': u'3851d47e-5fda30d441f1814fdb335ba5',
u'username': u'jayendra',
u'version': u'5.3'}}
When matlab encounter the error while executing the code, the status (under the content ) should be error instead of ok.
ref: https://jupyter-client.readthedocs.io/en/stable/messaging.html#request-reply
Thanks for the report! I guess we'll have to inspect the output, looking for text that indicates that the command has failed. I don't have a Matlab license, so we'll either need some examples of what failing code looks like, or someone to submit a PR.
This stream msg would help to identify the error, note the stderr inside the content.
{'buffers': [],
'content': {u'name': u'stderr',
u'text': u'\x1b[0;31mError: This statement is incomplete.\n\n\x1b[0m'},
'header': {u'date': datetime.datetime(2018, 10, 4, 11, 7, 11, 925105, tzinfo=tzutc()),
u'msg_id': u'ae0f8e8d-fb5257f1bab440ad8bc66045',
u'msg_type': u'stream',
u'session': u'4265b9d2-421472de0dd6c27018d449f1',
u'username': u'jayendra',
u'version': u'5.3'},
'metadata': {},
'msg_id': u'ae0f8e8d-fb5257f1bab440ad8bc66045',
'msg_type': u'stream',
'parent_header': {u'date': datetime.datetime(2018, 10, 4, 11, 7, 6, 341136, tzinfo=tzutc()),
u'msg_id': u'f23dd5f3-500af3c70424254c974c5be6',
u'msg_type': u'execute_request',
u'session': u'8931edbb-bebf82a3b871155c66129acd',
u'username': u'jayendra',
u'version': u'5.3'}}
I can share the whole output if you need it.
We could just declare that any output on stderr indicates that there was an error (especially if there were also no stdout output). That may not be 100% correct as one could (maybe?) output to stderr without it being an actual error?
Looks like that is what check_exitcode is for:
metakernel/metakernel/process_metakernel.py
Lines 116 to 120 in 0d5dafe
yes output from stderr doesn't always indicate a error, for example fprintf(2,'Hello') would write to stderr, and it is not erroneous code. We can't use output from stderr as flag for error!!
I don't know how check_exitcode would be called.
check_exitcode is already called, but in matlab_kernel we can override it to look for whatever is the clue that an error just occured. I just don't know what that clue would be.
Can you help me on debugging that ?
Currently I am trying this, but I don't think this is the way to run the kernel.
In [1]: from matlab_kernel.kernel import MatlabKernel
In [2]: kernel = MatlabKernel()
In [3]: kernel.do_execute_direct('magic(4)')
---------------------------------------------------------------------------
IOErrorTraceback (most recent call last)
/usr/lib/python2.7/threading.pyc in __bootstrap(self)
772 # if a non-daemonic encounters this, something else is wrong.
773 try:
--> 774 self.__bootstrap_inner()
775 except:
776 if self.__daemonic and _sys is None:
/usr/lib/python2.7/threading.pyc in __bootstrap_inner(self)
812 if _sys and _sys.stderr is not None:
813 print>>_sys.stderr, ("Exception in thread %s:\n%s" %
--> 814 (self.name, _format_exc()))
815 elif self.__stderr is not None:
816 # Do the best job possible w/o a huge amt. of code to
IOError: [Errno 9] Bad file descriptor
I think you can run the kernel that way (at least I can run other metakernels that way). But perhaps you should use python (rather than ipython) and maybe python3 instead of python2.
same things is happening with python2 and python3
Python 3.6.6 (default, Sep 12 2018, 18:26:19)
[GCC 8.0.1 20180414 (experimental) [trunk revision 259383]] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from matlab_kernel.kernel import MatlabKernel
>>> kernel = MatlabKernel()
>>> kernel.do_execute_direct('magic(4)')
Exception in thread Thread-2:
Traceback (most recent call last):
File "/usr/lib/python3.6/threading.py", line 916, in _bootstrap_inner
self.run()
File "/usr/lib/python3.6/threading.py", line 864, in run
self._target(*self._args, **self._kwargs)
File "/home/jayendra/.local/lib/python3.6/site-packages/matlab_kernel/wurlitzer.py", line 148, in forwarder
handler(data)
File "/home/jayendra/.local/lib/python3.6/site-packages/matlab_kernel/wurlitzer.py", line 96, in _handle_stdout
self._stdout.write(self._decode(data))
File "/home/jayendra/.local/lib/python3.6/site-packages/metakernel/_metakernel.py", line 631, in Print
self.send_response(self.iopub_socket, 'stream', stream_content)
File "/home/jayendra/.local/lib/python3.6/site-packages/ipykernel/kernelbase.py", line 463, in send_response
return self.session.send(stream, msg_or_type, content, self._parent_header,
AttributeError: 'NoneType' object has no attribute 'send'
Traceback (most recent call last):
Python 2.7.15rc1 (default, Apr 15 2018, 21:51:34)
[GCC 7.3.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from matlab_kernel.kernel import MatlabKernel
>>> kernel = MatlabKernel()
>>> kernel.do_execute_direct('magic(4)')
self.__bootstrap_inner()
File "/usr/lib/python2.7/threading.py", line 814, in __bootstrap_inner
(self.name, _format_exc()))
IOError: [Errno 9] Bad file descriptor
I have checked the #149 which is similar to this scenario, except the octave vs matlab distinction.
With matlab.engine I think this should be easier to do for matalab case then the octave, because it raises the MatlabExecutionError whenever there is an actual error.
I am trying to understand the flow of execution, and I think it is like
_metakernel.MetaKernel.do_execute --> kernel.MatlabKernel.do_execute_direct.
The do_execute method here
metakernel/metakernel/_metakernel.py
Line 381 in 0d5dafe
retval from the do_execute_direct here https://github.com/Calysto/matlab_kernel/blob/master/matlab_kernel/kernel.py#L84 , which should be object of ExceptionWrapper metakernel/metakernel/_metakernel.py
Line 51 in 0d5dafe
I think this is the issue which needs to be fixed, correct me if I am wrong.
That sounds right. Thanks for looking into this!