Airflow DAG: How to insert data into a table using Python operator, not BigQuery operator?

Question

I am trying to insert some data into a table using a simple Python operator, not the BigQuery operator, but I am unsure how to implement this. I am trying to implement this in the form of an Airflow DAG.

I have written a simple DAG, and I have managed to use the following to insert the data from a GCS Bucket to BigQuery, but I am wanting to do this using a Python operator instead, not BigQuery:

load_csv = gcs_to_bq.GoogleCloudStorageToBigQueryOperator(
    task_id='gcs_to_bq_example',
    bucket='cloud-samples-data',
    source_objects=['bigquery/us-states/us-states.csv'],
    destination_project_dataset_table='airflow_test.gcs_to_bq_table',
    schema_fields=[
        {'name': 'name', 'type': 'STRING', 'mode': 'NULLABLE'},
        {'name': 'post_abbr', 'type': 'STRING', 'mode': 'NULLABLE'},
    ],
    write_disposition='WRITE_TRUNCATE',
    dag=dag)

I am wanting to achieve the above using a simple Python operator instead of BigQuery.

Asked By: shrewd.jude

||

Source

Answer 1

You can use BigQuery Python client in a PythonOperator to insert GCS files to BigQuery, example :

PythonOperator(
    task_id="gcs_to_bq",
    op_kwargs={
      'dataset': 'dataset',
      'table': 'table'
    },
    python_callable=load_gcs_files_to_bq
)

def load_gcs_files_to_bq(dataset, table):
   from google.cloud import bigquery

   # Construct a BigQuery client object.
   client = bigquery.Client()

   # TODO(developer): Set table_id to the ID of the table to create.
   table_id = f"your-project.{dataset}.{table}"

   job_config = bigquery.LoadJobConfig(
        schema=[
             bigquery.SchemaField("name", "STRING"),
             bigquery.SchemaField("post_abbr", "STRING"),
        ],
        skip_leading_rows=1,
        # The source format defaults to CSV, so the line below is optional.
        source_format=bigquery.SourceFormat.CSV,
    )
    
    uri = "gs://cloud-samples-data/bigquery/us-states/us-states.csv"

    load_job = client.load_table_from_uri(
        uri, table_id, job_config=job_config
    )  # Make an API request.

    load_job.result()  # Waits for the job to complete.

    destination_table = client.get_table(table_id)  # Make an API request.
    print("Loaded {} rows.".format(destination_table.num_rows))

Answered By: Mazlum Tosun

Airflow DAG: How to insert data into a table using Python operator, not BigQuery operator?

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