Debugger Timedout if kept idle for some time

[shyamiisc]

Environment data

• PTVSD version: 2020.6.90262
• OS and version: Mac OS and 10.15.3
• Python version (& distribution if applicable, e.g. Anaconda): 3.7.6
• Using VS Code or Visual Studio: VS Code and Version: 1.46.1

Actual behavior

We are using ptvsd in some what different way. We embedded python interpreter in a C++ application. We are using ptvsd to debug the scripts which is written using the API provided by our application. To do that We load PTVSD module in the embedded python interpreter and open a socket to set up a remote debugging session with VSCode. It was working fine so far but now we started seeing timeout issue showing below message where debugging is stopped if kept idle for around 30 seconds.

Exception in thread ptvsd.Server:
Traceback (most recent call last):
File "/Users/goyals/.vscode/extensions/ms-python.python-2019.9.34911/pythonFiles/lib/python/ptvsd/ipcjson.py", line 269, in process_one_message
msg = self.__message.pop(0)
IndexError: pop from empty list

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/Users/goyals/Library/Application Support/Autodesk/webdeploy/feature--ChangesFromAPIPerforceBranch/5fe9cf01e67436462626acce9bec5ab16b7b3fb7/Autodesk Fusion 360.app/Contents/Frameworks/Python.framework/Versions/Current/lib/python3.7/threading.py", line 926, in _bootstrap_inner
self.run()
File "/Users/goyals/Library/Application Support/Autodesk/webdeploy/feature--ChangesFromAPIPerforceBranch/5fe9cf01e67436462626acce9bec5ab16b7b3fb7/Autodesk Fusion 360.app/Contents/Frameworks/Python.framework/Versions/Current/lib/python3.7/threading.py", line 870, in run
self._target(*self._args, **self._kwargs)
File "/Users/goyals/.vscode/extensions/ms-python.python-2019.9.34911/pythonFiles/lib/python/ptvsd/wrapper.py", line 536, in process_messages
raise exc
File "/Users/goyals/.vscode/extensions/ms-python.python-2019.9.34911/pythonFiles/lib/python/ptvsd/wrapper.py", line 521, in process_messages
self.process_messages()
File "/Users/goyals/.vscode/extensions/ms-python.python-2019.9.34911/pythonFiles/lib/python/ptvsd/ipcjson.py", line 258, in process_messages
self.process_one_message()
File "/Users/goyals/.vscode/extensions/ms-python.python-2019.9.34911/pythonFiles/lib/python/ptvsd/ipcjson.py", line 272, in process_one_message
self._wait_for_message()
File "/Users/goyals/.vscode/extensions/ms-python.python-2019.9.34911/pythonFiles/lib/python/ptvsd/ipcjson.py", line 154, in _wait_for_message
line = self._buffered_read_line_as_ascii()
File "/Users/goyals/.vscode/extensions/ms-python.python-2019.9.34911/pythonFiles/lib/python/ptvsd/ipcjson.py", line 113, in _buffered_read_line_as_ascii
temp = self.__socket.recv(1024)
socket.timeout: timed out

A similar issue is reported here #1113.

I tried setting timeout property to a higher number in launch.json as suggested by some other user's post but that did not help. I am not sure if the connection is dropped by VSCode debug adapter if there is no response in a specified time.

I appreciate if you can provide any suggestion on what might be going wrong here and there is any way we can increase the default time out duration from 30 seconds to some higher number. Thanks.

[shyamiisc]

Hi @karthiknadig, Do you have any suggestion on this? Thanks.

[int19h]

You should switch to https://github.com/microsoft/debugpy for embedding.

If you update your VSCode Python extension, it should take care of the same on client side. Judging by your log, the version you're on is ms-python.python-2019.9.34911, which is very old.

[shyamiisc]

Hi Pavel, I switched to older version to check if is extension version issue or something else. ms-python.python-2019.9.34911 version was working well for us hence tried with it. This problem is happening even with ms-python.python-2020.6.91350.

Just to provide more context this is how we are embedding PTVSD. The following script is executed by the python interpreter embedded in the application
import ptvsd
ptvsd.enable_attach(address=('127.0.0.1','9000')))

and then we wait for the VSCode to attach using wait_for_attach method
import ptvsd
ptvsd.wait_for_attach()

As you suggested We will look into debugpy for embedding. Thanks.

[shyamiisc]

ptvsd-12672.log
@int19h Attaching a log file for your reference. Thanks for taking a look at it.

[int19h]

To clarify, the newer versions of the Python extensions use debugpy on the client. They might work with ptvsd on the server, but that's an inherently less stable combination.

We're not doing bug fixes in ptvsd at this point - debugpy has diverged so far, the entire layer above pydevd is a complete rewrite, so they're impossible to backport (and some of the problems in ptvsd 4 were architectural, requiring such a rewrite to fix).

[marcosscriven]

@shyamiisc - ironically I found this issue by Googling Fusion 360 debugpy, as I'm trying to debug a Fusion 360 add-in remotely (I.e. a different computer on the network) and it refuses to connect.

Can Fusion 360 Python version be updated per @int19h's suggestion?