Support authentification to several polytope servers

[observingClouds]

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

In projects like DE330 we need to access several polytope servers (e.g. ECMWF, LUMI databridge). Is there a way to provide several token in e.g. ~/.polytopeapirc or ~/.ecmwfapirc such that the polytope client selects the correct one automatically?

Just like for S3 buckets and their ~/.aws/credentials file, it would be good to support something along those lines, like:

[ecmwf-atos]
endpoint_url = https://polytope-test.ecmwf.int
access_token = "none_of_your_business"

[lumi-databridge]
endpoint_url = polytope.lumi.apps.dte.destination-earth.eu
access_token = "none_of_your_business"

This would make many downstream applications much easier.

Describe the solution you'd like

Support for multiple polytope authentification credentials.

Describe alternatives you've considered

No response

Additional context

No response

Organisation

No response

[peshence]

Hello @observingClouds we will likely do something of the sort, but until then you can add your user_key at client creation or in earthkit.data.from_source like so

c = Client(
    address="some polytope",
    user_key="key",
)

or

data = earthkit.data.from_source(
    "polytope",
    "destination-earth",
    request,
    address="some polytope",
    user_key="key",
)

[observingClouds]

Thanks @peshence for your response. Glad to hear you guys are thinking about adapting the standards used for the S3 protocol.

Creating several clients works of course but is not really an option when you do not want to hard-code the key (or create several environment variables) and read from several polytope servers at the same time.