nightly build health checks and failing notebooks

[brian-rose]

Currently we set allow_errors: True in our jupyter book _config.yml. This means that if a cell in a notebook throws an error, the build continues and reports success.

So our "health checks" as shown in the nightly build badges aren't really measuring whether the notebooks run.

I wonder if we should toggle the allow_errors setting just for the nightly build, while keeping it for other builds. (At least during the development phase it's very useful to be able to see the rendered book with the errors included)

[kmpaul]

Personally, I think a True/False toggle is not enough. There may be times in notebooks where, for demonstration purposes, you want to generate an error. So, there should be a way of checking for expected failures. To enable this, I think we need a different mechanism. For that, I think we want the Jupyter Book config to set allow_errors: True, and then we should test the results of each notebook cell against a specific rule. One approach might be nbmake, which you can read a simple blog about here.

[dcamron]

Takeaway from today's IWG: encourage allow_errors: False to get an idea of overall cookbook health and test its interaction with per-cell raises-exception tags to make sure we can still support @ktyle's mentioned use-case here.

[brian-rose]

Takeaway from today's IWG: encourage allow_errors: False to get an idea of overall cookbook health and test its interaction with per-cell raises-exception tags to make sure we can still support @ktyle's mentioned use-case here.

Yes, this won't catch every instance that we might ideally want to flag (e.g. a cell executes but produces nonsensical results because of bad data), but it will be a big step forward in terms of finding errors through our regular health checks.

[brian-rose]

Looks like I misspoke at yesterday's IWG. We still have allow_errors: True in the template config file.

Some existing cookbooks remove that line and thus get the default allow_errors: False. One example is the CMIP6 Cookbook.

Action items here to close this issue:

• remove allow_errors: True from the template and existing cookbooks
• add some documentation to Cookbook contributor's guide about setting the raises-exception tag.