Readme and notebook on using Zarr on CESNET Swift

[guillaumeeb]

Work on #14 and discussion.

I added a Readme with all the necessary things to do to obtain authentication for Swift. But I could not go to the end as I'm currently experiencing errors (in discussion with @sebastian-luna-valero).

I also prepared a notebook for testing S3, Swift access and various libraries. In the end the notebook propose some rough performance tests on the object storage. I couldn't test all of it.

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[guillaumeeb]

So I solved the problem with getting correct values for Swift URL and AUTH_KEY, and also the problem I add when using aa Dask Cluster (zarr-swift not installed on workers, classic). This is ready for a review.

As this is just a first test (and not real performance test and all), review can just be some high level ideas or suggestions, or typos also!

[guillaumeeb]

Something I did not dig into is the consolidate=true kwarg, did not have the time to check what it implies when creating a Zarr dataset with Xarray.

[sebastian-luna-valero]

Thanks!

My suggestions below.

[sebastian-luna-valero]

Adding how to create S3 credentials at CESNET

[tinaok]

Hi, I have a test pangeo config to run, but I need to make some part of data available only for a few user. Is it possible to create Zarr file on Cesnet's swift 'private' (the owner) 'group' (some of people who have access to pangeo-eosc platform) and 'public' internet open ?

[guillaumeeb]

@tinaok I think that you should open a new issue for this question (and I'm not sure if it can be easily answered).

@sebastian-luna-valero I think I answered all your comments, and I've updated this notebook to take S3 writes into account.

[guillaumeeb]

@tinaok I've opened #17 to discuss your need.

[guillaumeeb]

I'm gonna merge this, because it gives a first working base to use CESNET object storage. Feel free to open issues or PR to improve it!