Add HostType to HostMetadata

[tanmay-db]

Python SDK — PR #1370: [Internal] Add HostType to HostMetadata

🥞 Stacked PR

• hosttype-metadata [Files
  changed]
  • default-oidc-audience [[Files
    changed](https://github.com/Default OIDC audience #1371/files/f48e10283426bda51b2e
    f18c218ec019d51de3c9..ca751ee)]
    • hosttype-resolved [[Files
      changed](https://github.com/Hosttype resolved #1372/files/ca751eebb5ffcd689c678
      475b0f60bcf8c4180da..6aabd40)]

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Summary

Parses the host_type field from the /.well-known/databricks-config discovery endpoint into
HostMetadata and stores it on Config, so the SDK knows whether a host is a workspace,
account, or unified host without parsing hostnames.

Why

Today, the host_type property infers the host type by prefix-matching the hostname against
accounts. — everything else is classified as WORKSPACE. This cannot detect unified hosts,
which share the same hostname pattern as workspace hosts.

The server-side host_type field is being added to the /.well-known/databricks-config
endpoint, returning "workspace", "account", or "unified". This PR threads that value
into the SDK so it's available for use when the host_type property is updated to prefer
endpoint-resolved values over URL-based inference (PR #1372).

What changed

Interface changes

• HostType.from_api_value(value) — new static method that normalizes API values
  (workspace, account, unified) to enum constants. Case-insensitive. Returns None for
  unknown values.
• HostMetadata.host_type — new field parsed from the discovery endpoint response.

Behavioral changes

• _resolve_host_metadata() now populates Config._resolved_host_type from the discovery
  endpoint if not already set. The host_type property is not yet modified to use this
  value — that is PR Hosttype resolved #1372 in this stack.

Internal changes

• Config._resolved_host_type stores the host type resolved during
  _resolve_host_metadata().

How is this tested?

• 18 unit tests covering from_api_value() normalization, HostMetadata.from_dict() parsing,
  _resolve_host_metadata population, and does-not-overwrite semantics.

NO_CHANGELOG=true

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Inputs:

• PR number: 1370
• Commit SHA: 32e3131473be4c2833c4adf8f70c779232f9a8fb

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