ATTACH Iceberg catalog: endpoint URI not exposed for OpenLineage dataset namespace

[malon64]

Summary

When using dbt-duckdb with an ATTACH-based Iceberg REST catalog (e.g. Apache Polaris), the OpenLineage dataset namespace is derived from the local DuckDB file path (duckdb:///tmp/my_db.duckdb) rather than from the attached catalog endpoint URI.

The adapter knows the Iceberg endpoint for each ATTACH alias, but this information is not surfaced to OpenLineage integrations (e.g. openlineage-dbt), which fall back to the DuckDB file path as the namespace.

Profile configuration

local_runtime:
  type: duckdb
  path: "/tmp/openlakeforge-sales-dbt.duckdb"
  attach:
    - path: "sales_dev"
      alias: sales_dev
      options:
        type: iceberg
        endpoint: "http://polaris:8181/api/catalog"

dbt_project.yml

models:
  my_project:
    +database: sales_dev      # matches the ATTACH alias
    +schema: gold
    +materialized: iceberg_table

Actual OL dataset emitted by openlineage-dbt

{
  "namespace": "duckdb:///tmp/openlakeforge-sales-dbt.duckdb",
  "name": "sales_dev.gold.mart_revenue_by_product"
}

Expected OL dataset

{
  "namespace": "http://polaris:8181/api/catalog",
  "name": "sales_dev.gold.mart_revenue_by_product"
}

Because the namespace does not match any registered catalog service (e.g. in OpenMetadata), the lineage edge is silently dropped even though the dataset name itself is correct.

Root cause

openlineage-dbt calls into the dbt adapter to determine the dataset namespace. For dbt-duckdb, it reads credentials.path (the local DuckDB file). The ATTACH endpoint — which is the authoritative catalog URI for any model whose database matches the alias — is not exposed through any standard dbt adapter interface.

Proposed fix

dbt-duckdb should expose the ATTACH catalog endpoint for OpenLineage-aware integrations. Two possible approaches:

Option A — dispatch macro
Implement a dbt_duckdb__get_openlineage_dataset_namespace(relation) dispatch macro that, for a given relation, checks if relation.database matches an ATTACH alias with options.type: iceberg, and returns options.endpoint if so.

Option B — connection metadata
Expose an ATTACH alias → endpoint mapping on the connection credentials object so that openlineage-dbt (or any other OL integration) can look up the correct namespace from the adapter's credentials.

Environment

• dbt-duckdb 1.9.6
• dbt-core 1.9.x
• openlineage-dbt 1.16
• Apache Polaris 1.0.0
• OpenMetadata 1.12.10
• Kubernetes (local kind cluster)