feat(bigquery): add bigquery_query_manifest_external_table sample to query an external table defined by a manifest file (#14715)

Problem:
The BigQuery documentation (https://cloud.google.com/bigquery/docs/query-open-table-format-using-manifest-files)
needs a standalone, tested Python code sample demonstrating how to
query an external table defined by a manifest file (region tag `bigquery_query_manifest_external_table`).

Solution:
- Add `query_manifest_external_table(project_id: str, dataset_id: str, table_id: str, manifest_uri: str) -> None` in `bigquery/biglake/bigquery_query_manifest_external_table.py`
  (Run a GoogleSQL query against an open-table-format external table backed by a manifest file on Cloud Storage.)
- Add unit tests (`bigquery/biglake/bigquery_query_manifest_external_table_test.py`) covering both the success
  path and API error handling (`GoogleAPICallError`)

Author: iennae

bigquery/biglake/bigquery_query_manifest_external_table.py

@@ -0,0 +1,83 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# [START bigquery_query_manifest_external_table]
+import sys
+
+from google.api_core import exceptions
+from google.cloud import bigquery
+
+
+def query_manifest_external_table(
+    project_id: str,
+    dataset_id: str,
+    table_id: str,
+    manifest_uri: str,
+) -> None:
+    """Configures a newline-delimited manifest on an external table and queries it.
+
+    Args:
+        project_id: Google Cloud project ID (for example, 'example-project').
+        dataset_id: BigQuery dataset ID containing the external table
+            (for example, 'example_dataset').
+        table_id: BigQuery external table ID
+            (for example, 'example_manifest_table').
+        manifest_uri: Cloud Storage URI of the newline-delimited manifest file
+            (for example, 'gs://example-bucket/manifests/symlink.manifest').
+    """
+    client = bigquery.Client(project=project_id)
+    table_ref = f"{project_id}.{dataset_id}.{table_id}"
+
+    # Setting FILE_SET_SPEC_TYPE_NEW_LINE_DELIMITED_MANIFEST tells BigQuery to treat each line
+    # in manifest_uri as a Cloud Storage data file URI rather than reading the manifest as CSV data.
+    external_config = bigquery.ExternalConfig("CSV")
+    external_config.source_uris = [manifest_uri]
+    external_config.file_set_spec_type = (
+        "FILE_SET_SPEC_TYPE_NEW_LINE_DELIMITED_MANIFEST"
+    )
+
+    table = bigquery.Table(table_ref)
+    table.external_data_configuration = external_config
+
+    query = (
+        "SELECT id, label, score " f"FROM `{table_ref}` " "ORDER BY id ASC " "LIMIT 10"
+    )
+
+    try:
+        print(f"Configuring manifest URI and querying external table: {table_ref}")
+        client.update_table(table, ["external_data_configuration"])
+        query_job = client.query(query)
+        rows = list(query_job.result())
+    except exceptions.NotFound as err:
+        print(
+            f"error: manifest external table '{table_id}' in dataset '{dataset_id}' "
+            f"for project '{project_id}' (manifest '{manifest_uri}') was not found: {err.message}",
+            file=sys.stderr,
+        )
+        return
+    except exceptions.GoogleAPICallError as err:
+        print(
+            f"error: could not query manifest external table '{table_id}' in dataset "
+            f"'{dataset_id}' for project '{project_id}' (manifest '{manifest_uri}'): {err.message}",
+            file=sys.stderr,
+        )
+        return
+
+    print(f"Resource ID: {table_ref}")
+    print(f"Job ID: {query_job.job_id}")
+    print(f"Manifest URI: {manifest_uri}")
+    print(f"Rows Returned: {len(rows)}")
+
+
+# [END bigquery_query_manifest_external_table]

bigquery/biglake/bigquery_query_manifest_external_table_test.py

@@ -0,0 +1,73 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from unittest import mock
+
+import bigquery_query_manifest_external_table
+from google.api_core import exceptions
+import pytest
+
+
+def test_query_manifest_external_table_success(
+    monkeypatch: pytest.MonkeyPatch,
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    mock_client = mock.MagicMock()
+    mock_job = mock.MagicMock()
+    mock_job.job_id = "example-job-123"
+    mock_job.statement_type = "SCRIPT"
+    mock_row = mock.MagicMock()
+    mock_job.result.return_value = [mock_row]
+    mock_client.query.return_value = mock_job
+    monkeypatch.setattr(
+        bigquery_query_manifest_external_table.bigquery,
+        "Client",
+        lambda project=None: mock_client,
+    )
+
+    bigquery_query_manifest_external_table.query_manifest_external_table(
+        project_id="example-project",
+        dataset_id="example_dataset",
+        table_id="example_manifest_table",
+        manifest_uri="gs://example-bucket/manifests/symlink.manifest",
+    )
+
+    captured = capsys.readouterr()
+    assert "Resource ID:" in captured.out
+    assert "example-project" in captured.out
+    assert mock_client.query.called
+
+
+def test_query_manifest_external_table_error(
+    monkeypatch: pytest.MonkeyPatch,
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    mock_client = mock.MagicMock()
+    mock_client.query.side_effect = exceptions.NotFound("resource error")
+    monkeypatch.setattr(
+        bigquery_query_manifest_external_table.bigquery,
+        "Client",
+        lambda project=None: mock_client,
+    )
+
+    bigquery_query_manifest_external_table.query_manifest_external_table(
+        project_id="example-project",
+        dataset_id="example_dataset",
+        table_id="example_manifest_table",
+        manifest_uri="gs://example-bucket/manifests/symlink.manifest",
+    )
+
+    captured = capsys.readouterr()
+    assert "error:" in captured.err
+    assert "example-project" in captured.err

bigquery/biglake/noxfile_config.py

@@ -0,0 +1,23 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+TEST_CONFIG_OVERRIDE = {
+    # You can opt out from the test for specific Python versions.
+    "ignored_versions": ["2.7", "3.7", "3.8", "3.9", "3.10", "3.11"],
+    # Enforce type hints on new samples.
+    "enforce_type_hints": True,
+    "gcloud_project_env": "GOOGLE_CLOUD_PROJECT",
+    "pip_version_override": None,
+    "envs": {},
+}

bigquery/biglake/requirements-test.txt

@@ -0,0 +1 @@
+pytest==9.0.3; python_version >= "3.10"

bigquery/biglake/requirements.txt

@@ -0,0 +1,2 @@
+google-cloud-bigquery==3.47.0
+google-cloud-bigquery-storage==2.43.0