Hi everyone,

Over the last week I have been working on implementing an importable config item (#785). As part of this PR, I have been discussing with @bouweandela and @Peter9192 if this would be a good time to rethink how the config file is structured. I would like to start a discussion on how to change the configuration.

There are several issues on the topc. I think with #785 we have made some strides towards tackling nearly all of them. In the next post I will detail we propose to set it up.

#794: Example config file could use some improvements
#793: "Default" is not a great name for a DRS in the configuration
#494: Support per dataset DRS
#129: Specify directory stucture per path instead of per project in config-user.yml
#100: Config-user.yml rootpath.
#93: Too many unnessary settings in config-user.yml
#64: Make user configuration file more user friendly
#2280: ignore .esmvaltool/config-user.yml when a custom --config-file is specified

In particular, I also want to draw your attention #93, to remove some settings from the default user config file. Which settings are really necessary, and which should be deprecated? Are there new keywords that should be added?

Suggestions from @bouweandela to be moved to the diagnostic script settings in the recipe (#93):
write_plots: true
write_netcdf: true
output_file_type: png # [ps]/pdf/png/eps/epsi
profile_diagnostic: false -> only interesting for Python diagnostic developers
save_intermediary_cubes: false -> for debugging purposes, probably only interesting for diagnostic developers
exit_on_warning: false -> specific to NCL diagnostics, probably only interesting for diagnostic developers
Using these options in the configuration file instead of the recipe would need to be deprecated in the upcoming release (2.1, planned for October 2020, feature freeze October 5th) and removed two releases later (2.3, planned June 2021), see also the release schedule.

Also:
config_developer_file: null -> No longer needed with the PR, could be tweaked to specify the default data reference syntax