xcube server to deliver data

[forman]

Is your feature request related to a problem? Please describe.

xcube serve does not yet allow for data access.

Describe the solution you'd like

The xcube web API should provide data access functions, e.g. the forms

• POST /datasets/{dataset}/data
• GET /datasets/{dataset}/data?<query-params>
• GET /datasets/{dataset}/data.zarr

In the first two forms a cube subset is reformatted and then made available for download. Hence, the response returns a binary stream. The <query-params> and the POST body provides the following parameters:

• bbox=<xmin>,<ymin>,<xmax>,<ymax> - optional bounding box for the output
• timeRange=<start>,<end> - optional time range for the output
• variables=<name1>,<name2>,...,<nameN> - optional output variables
• format=<format> - optional output format, where <format> is one of netcdf4, geotiff, zarr.zip, zarr. The latter creates an object storage view on the output using ZARR format.
• name=<name> - optional output name

The last form creates an object storage view on a dataset using ZARR format, so users can directly open entire data cubes, e.g.

from xcube.api import read_cube
cube = read_cube('https://myhost/api/datasets/s2a_10m/data.zarr') 
...

Describe alternatives you've considered

We may also implement an OGC CSW interface.

[forman]

@dzelge and @AliceBalfanz, could you please review proposed API and provide feedback and / or new use cases.

[forman]

Added web API for data access, slightly different than proposed initially:

• List bucket objects: /s3bucket, see AWS docs GET
• Get bucket object: /s3bucket/{ds_id}/{path}, see AWS docs HEAD and GET

See #117

[AliceBalfanz]

xcube server to deliver data