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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

Register a Unity Catalog table or OneLake item in Purview

This how-to drives the Register in Purview button on the Unified Catalog asset detail page. It is the cross-source bridge between Databricks Unity Catalog / Microsoft Fabric and Microsoft Purview Atlas.

What it does

When you click Register in Purview on a Unity Catalog table, Loom calls:

POST /api/catalog/register
{
  "source": "unity-catalog",
  "host": "adb-xxxx.azuredatabricks.net",
  "fullName": "main.bronze.customers",
  "domain": "<purview-businessDomainId-guid>"   (optional)
}

The BFF route then:

  1. Calls getTable(host, fullName) against the Unity Catalog REST API to confirm the table exists and to pull comment, owner, and name.

  2. Composes a deterministic Atlas qualifiedName:

    https://{host}/api/2.1/unity-catalog/tables/{fullName}

    Because qualifiedName is the Atlas dedup key, repeated registrations are idempotent — re-running the action updates rather than duplicates the entity.

  3. Calls POST /datamap/api/atlas/v2/entity with:

    {
  "entity": {
    "typeName": "databricks_table",
    "attributes": {
      "qualifiedName": "...",
      "name": "customers",
      "comment": "..."
    },
    "contacts": { "Expert": [ { "id": "owner@contoso.com", "info": "Owner" } ] },
    "classifications": [ { "typeName": "MICROSOFT.PERSONAL.NAME" } ],
    "businessDomainId": "<guid>"
  }
}

  4. Reads guidAssignments from the response and returns the newly-assigned (or existing) Atlas guid, plus a deep link to the Purview Unified Catalog UI:

    https://{LOOM_PURVIEW_ACCOUNT}.purview.azure.com/main.html#/asset/{guid}

The OneLake variant is the same shape with source: "onelake" and typeName: "fabric_lakehouse" (or fabric_warehouse); qualifiedName becomes https://onelake.dfs.fabric.microsoft.com/{workspaceId}/{itemId}.

Required configuration

Variable / role Where Required for
LOOM_PURVIEW_ACCOUNT Console env (wired by admin-plane/main.bicep when purviewEnabled = true) Reaching the Purview data plane
Data Curator + Data Product Owner on the Loom UAMI Purview portal → Governance domain Atlas write surface
Service principals can use Fabric APIs Power BI/Fabric admin portal OneLake getFabricItem
Unity Catalog METASTORE_ADMIN for the Loom UAMI Databricks admin via the helper script scripts/csa-loom/add-loom-uami-to-uc-metastore-admin.sh Reading UC table details

If LOOM_PURVIEW_ACCOUNT is not set the BFF returns 501 with a structured hint payload pointing to the exact bicep module + roles needed; the UI surfaces this in a Fluent UI MessageBar rather than failing silently.

Verification recipe

curl -s -X POST -H 'content-type: application/json' \
  -H "Cookie: loom_session=$(./scripts/csa-loom/mint-session.sh)" \
  -d '{"source":"unity-catalog","host":"adb-xxxx.azuredatabricks.net","fullName":"main.bronze.customers"}' \
  https://<console-host>/api/catalog/register

Successful response:

{
  "ok": true,
  "source": "unity-catalog",
  "typeName": "databricks_table",
  "qualifiedName": "https://adb-xxxx.azuredatabricks.net/api/2.1/unity-catalog/tables/main.bronze.customers",
  "guid": "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee",
  "purviewDeepLink": "https://purview-csa-loom-eastus2.purview.azure.com/main.html#/asset/aaaaaaaa-..."
}

Click the deep link to confirm Purview shows the registered table.