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CSA Loom — the Microsoft Fabric experience for Azure tenants where Fabric isn't yet available: lakehouses, warehouses, notebooks, semantic models, Activator rules, Data Agents, across Commercial, GCC, GCC-High, and DoD IL5

Catalog — Metastores

Inventory of every back-end the Unified Catalog federates over.

Endpoint

  • GET /api/catalog/metastores — list UC metastores (federated across workspaces, deduped by metastore_id), Fabric / OneLake workspaces, and the configured Purview account
  • POST /api/catalog/metastores body { source: 'unity-catalog', hostname } — probe a new Databricks workspace. Persistent registration still requires a bicep flip on LOOM_DATABRICKS_HOSTNAMES; the probe lets the admin pre-validate that the metastore admin group already includes the Loom UAMI before they push the bicep change.

Multi-workspace federation

The console reads LOOM_DATABRICKS_HOSTNAMES (comma-separated) and falls back to LOOM_DATABRICKS_HOSTNAME. Each workspace gets a separate AAD token + REST call; results are deduped so a metastore shared across multiple workspaces appears once. When a workspace is unreachable a synthetic ERROR_<hostname> row is returned so the operator sees which workspace is misconfigured (versus a single global 500 hiding the cause).

NotConfigured gates

  • Unity → if LOOM_DATABRICKS_HOSTNAMES/LOOM_DATABRICKS_HOSTNAME is unset, the page shows the structured hint with the env var name + bicep module
  • Fabric → if the UAMI is not in the Fabric service-principals tenant setting, the upstream 403 surfaces verbatim
  • Purview → if LOOM_PURVIEW_ACCOUNT is unset, the page renders an account-not-configured MessageBar