OpenDAP router

[abkfenris]

In between discussions on the xpublish repo, and the chat I had with Pangeo folks, there was interest in less frontend focused APIs too, with OpenDAP being chief among those.

I started exploring this a little bit, so I'm adding a few notes for whomever picks up this thread.

• https://github.com/xarray-contrib/xpublish/issues/105
• NCEI has created ZarrDAP which is a FastAPI app that already works with Zarr in S3.
  • https://github.com/NCEI-NOAAGov/zarrdap
  • It's in FastAPI already
  • It has a bit of a different dataset access API as compared to xpublish, so it might not be reasonable to combine the two directly, and the dataset access isn't overriddable the same way that xpublish is.
• opendap-protocol is a sans I/O implementation of the OpenDAP protocol
  • https://github.com/MeteoSwiss/opendap-protocol
  • This means we should be able to easily re-use it and wrap it in FastAPI responses.
  • Already plays nicely with Dask.
  • We will need to transform xarray datasets into it's native dataset API.
• Others:
  • https://pypi.org/project/dap/
  • https://pypi.org/project/Pydap/