added optimal install instructions for install from conda

[valeriupredoi]

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Please discuss your idea with the development team before getting started, to avoid disappointment later. The way to do this is to open a new issue on GitHub. If you are planning to modify an existing functionality, please discuss it with the original author(s) by tagging them in the issue.

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Tasks

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New recipe/diagnostic

• Add documentation for the recipe to the doc/sphinx/source/recipes folder and add a new entry to index.rst
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New data reformatting script

• Test the CMORized data using recipes/example/recipe_check_obs.yml, to make sure the CMOR checks pass without errors
• Add the new dataset to the table in the documentation
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Modified data reformatting script

• Test the CMORized data using recipes/example/recipe_check_obs.yml, to make sure the CMOR checks pass without errors
• Tag @mattiarighi in this pull request, so that the updated dataset can be added to the OBS data pool at DKRZ and synchronized with CEDA-Jasmin

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A lot of the discussion that led to this PR is here ESMValGroup/ESMValCore#660

@mattiarighi @bouweandela @jvegasbsc @schlunma need you guys to test the installation from conda (not from source) following these steps pls, can you pls use \time when running conda install, it'd be great to get a feel of how it performs on various platforms 🍺

[mattiarighi]

This holds for the base environment, shouldn't this be: miniconda3/envs/esmvaltool/bin/ or another env?

[valeriupredoi]

no, you don't need to create an environment when installing directly from conda, it's just like installing any other software package by typing just one command (well, three commands in our case) 🍺

[bouweandela]

There is no need to try to link julia to the conda environment: so long as the julia executable can be found in one of the directories listed in PATH things should work fine

[bouweandela]

I think it would be better to just point users to the site with the julia installation instructions: https://julialang.org/downloads/platform/ or https://julialang.org/downloads/platform/#linux_and_freebsd if we want to be specific. If these instructions change, ours will become outdated.

[valeriupredoi]

no, if those change we change the documentation too; man, a lot of the users prefer copy-paste instructions and going to see another set of instructions is already tedious for them 🍺

[valeriupredoi]

There is no need to try to link julia to the conda environment: so long as the julia executable can be found in one of the directories listed in PATH things should work fine

correct! change that line if you think it's better to append to $PATH, man, up to you

[bouweandela]

While this works at the moment (see ESMValGroup/ESMValCore#660) this is usually not the most reliable way to install the package. There have been several occasions where conda failed to install esmvaltool into existing environments, because it was incompatible with the packages already installed and didn't know how to resolve that.

[valeriupredoi]

that is not cool at all on conda's part because it should supersede those dependencies that are already installed from installing esmvalcore gah

[bouweandela]

@valeriupredoi I think this can be closed, because I added very similar instructions for installing julia in #1971 on your request. What do you think?

[valeriupredoi]

yep we can bin it 🗑️