Timeout configuration in validation and error message

[tuncbkose]

Make timeout configuration work via:

• either c.Execute.timeout or c.ExecutePreprocessor.timeout in nbgrader_config.py or,
• --Execute.timeout or --ExecutePreprocessor.timeout in the command-line.

Since #1690 is now merged, this pr also makes error_on_timeout configurable and makes it actually printed on command line or included in Notebook/Lab response messages.

In the case of validating, the current implementation does not use configuration in the way traitlets expects, in that it just calls preprocessor({"timeout": x}), which is caught by ExecutePreprocessor (this may work, but only by accident). By giving the argument parent=self, the configuration is deferred to the initialization of Configurable, which knows how to do it properly.

[github-actions]

👈 Launch a Binder on branch AaltoSciComp/nbgrader/timeout

[tuncbkose]

I see that #1690 implements timeout configuration like this, but better. The validate part of this pr is still worth considering in my opinion. I can force-push to keep only that part if requested

[tuncbkose]

The commit above makes error_on_timeout configurable and makes it actually printed on command line or included in Notebook/Lab response messages.

[tuncbkose]

Different behavior on Windows? I can try to get a machine to take a closer look, but that might not happen soon.

[tuncbkose]

I don't exactly understand the details, but the Windows errors were seemingly caused by timeout being set too short. Setting it to 2 seconds is fine, but when it is only 1, my guess is that the kernel gets cancelled too fast for nbclient to handle. I'll try to investigate more and make an issue for nbclient if appropriate.

[brichet]

Thanks @tuncbkose, LGTM.
I just have a comment below.

[tuncbkose]

The nbextensions failures seem to be related to the new selenium version deprecating service_log_path in nbgrader/tests/nbextensions/conftest.py::_make_browser
Edit: created #1789 to fix this

[tuncbkose]

Rebased for testing fixes

[brichet]

Thanks, LGTM.

I only have some prettier suggestions.

[tuncbkose]

Thank you! Will amend these suggestions in a bit.