如何在 BigQuery javascript UDF 中断言

Question

I would like to assert invariants in my Javascript UDF in BigQuery. Specifically, the query enclosing the UDF should fail gracefully if the invariant is violated. Is there a way to call an assert function to achieve this behavior?

Answer 1

You can use a test in Python with PyTest that uses BigQuery Python client to execute a sql query with your udf , then add your expected assertions:

from google.cloud import bigquery

def test_query_udf():
    client = bigquery.Client()
    query_job = client.query(
        """
        SELECT
          `{{project_id}}.{{dataset}}`.my_udf('my_param')
        FROM `{{project_id}}.{{dataset}}.table`
        """
    )

    results = query_job.result()  # Waits for job to complete.
    
    # Add your assertions on results

For this kind of integration tests, you have to launch it in an existing infrastructure.

Sometimes for integrations developers prefer using a short lived infra but it's not easy to manage.