Better URL / routing design

[sergiimk]

For kamu-web-ui we designed a nice routing scheme that maximally avoids collisions between /{account}/{dataset} paths and other application endpoints.

As the set of supported protocols grows we are facing the same issue in kamu-node, where endpoints like /query introduce ambiguity with accounts.

We want to get this under control and avoid the chance of collisions.

We should:

• Consider how important having /{account}/{dataset} as a root-level endpoint is for the node, as perhaps we can achieve this URL brevity and convenience for users through some additional level of indirection that happens under the hood.
• Introduce major version /v1/ into path for upgradeability

[sergiimk]

How about all HTTP-based APIs we separate by /protocol prefix:

• /graphql
• /odf/v1/:account/:dataset/blocks/head
• /odata/v3/$metadata

All other APIs (e.g. FlightSQL) will exist on distinct ports.

To preserve nice concise URLs:

• User does kamu login frontend.opendatafabric.net
• Login flow returns node URL as odf+https://node.opendatafabric.net/odf/
• Node URL is registered as a repo named frontend.opendatafabric.net that resolves to above URL
• Therefore kamu push my.dataset frontend.opendatafabric.net becomes a push to odf+https://node.opendatafabric.net/odf/my.account/my.dataset/push

It's unclear how to handle kamu pull odf+https://frontend.opendatafabric.net/my.account/my.dataset. This would likely require frontend to understand that ODF protocol is requested and redirect user to the node URL.