Update an existing routine resource.

## Code sample

### Go


Before trying this sample, follow the Go setup instructions in the
[BigQuery quickstart using
client libraries](https://docs.cloud.google.com/bigquery/docs/quickstarts/quickstart-client-libraries).


For more information, see the
[BigQuery Go API
reference documentation](https://godoc.org/cloud.google.com/go/bigquery).


To authenticate to BigQuery, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/bigquery/docs/authentication#client-libs).

    import (
    	"context"
    	"fmt"

    	"cloud.google.com/go/bigquery"
    )

    // updateRoutine demonstrates updating an existing BigQuery UDF using the routine API.
    func updateRoutine(projectID, datasetID, routineID string) error {
    	// projectID := "my-project-id"
    	// datasetID := "mydatasetid"
    	// routineID := "myroutineid"
    	ctx := context.Background()

    	client, err := bigquery.NewClient(ctx, projectID)
    	if err != nil {
    		return fmt.Errorf("bigquery.NewClient: %w", err)
    	}
    	defer client.Close()

    	routineRef := client.Dataset(datasetID).Routine(routineID)

    	// fetch existing metadata
    	meta, err := routineRef.Metadata(ctx)
    	if err != nil {
    		return fmt.Errorf("couldn't retrieve metadata: %w", err)
    	}

    	// Due to a limitation in the backend, supply all the properties for update.
    	update := &bigquery.https://docs.cloud.google.com/go/docs/reference/cloud.google.com/go/bigquery/latest/index.html#cloud_google_com_go_bigquery_RoutineMetadataToUpdate{
    		Type:        meta.Type,
    		Language:    meta.Language,
    		Arguments:   meta.Arguments,
    		Description: meta.Description,
    		ReturnType:  meta.ReturnType,
    		Body:        "x * 4",
    	}

    	if _, err := routineRef.Update(ctx, update, meta.ETag); err != nil {
    		return fmt.Errorf("update failed: %w", err)
    	}

    	return nil
    }

### Java


Before trying this sample, follow the Java setup instructions in the
[BigQuery quickstart using
client libraries](https://docs.cloud.google.com/bigquery/docs/quickstarts/quickstart-client-libraries).


For more information, see the
[BigQuery Java API
reference documentation](https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/overview).


To authenticate to BigQuery, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/bigquery/docs/authentication#client-libs).

    import com.google.cloud.bigquery.https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQuery.html;
    import com.google.cloud.bigquery.https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQueryException.html;
    import com.google.cloud.bigquery.https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQueryOptions.html;
    import com.google.cloud.bigquery.https://docs.cloud.google.com/java/docs/reference/google-cloud-analyticshub/latest/com.google.cloud.bigquery.analyticshub.v1.Routine.html;
    import com.google.cloud.bigquery.https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.RoutineId.html;

    // Sample to update routine
    public class UpdateRoutine {

      public static void main(String[] args) {
        // TODO(developer): Replace these variables before running the sample.
        String datasetName = "MY_DATASET_NAME";
        String routineName = "MY_ROUTINE_NAME";
        updateRoutine(datasetName, routineName);
      }

      public static void updateRoutine(String datasetName, String routineName) {
        try {
          // Initialize client that will be used to send requests. This client only needs to be created
          // once, and can be reused for multiple requests.
          https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQuery.html bigquery = https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQueryOptions.html.getDefaultInstance().getService();

          https://docs.cloud.google.com/java/docs/reference/google-cloud-analyticshub/latest/com.google.cloud.bigquery.analyticshub.v1.Routine.html routine = bigquery.https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQuery.html#com_google_cloud_bigquery_BigQuery_getRoutine_com_google_cloud_bigquery_RoutineId_com_google_cloud_bigquery_BigQuery_RoutineOption____(RoutineId.of(datasetName, routineName));
          routine.https://docs.cloud.google.com/java/docs/reference/google-cloud-analyticshub/latest/com.google.cloud.bigquery.analyticshub.v1.Routine.html#com_google_cloud_bigquery_analyticshub_v1_Routine_toBuilder__().setBody("x * 4").build().update();
          System.out.println("Routine updated successfully");
        } catch (https://docs.cloud.google.com/java/docs/reference/google-cloud-bigquery/latest/com.google.cloud.bigquery.BigQueryException.html e) {
          System.out.println("Routine was not updated. \n" + e.toString());
        }
      }
    }

### Python


Before trying this sample, follow the Python setup instructions in the
[BigQuery quickstart using
client libraries](https://docs.cloud.google.com/bigquery/docs/quickstarts/quickstart-client-libraries).


For more information, see the
[BigQuery Python API
reference documentation](https://docs.cloud.google.com/python/docs/reference/bigquery/latest).


To authenticate to BigQuery, set up Application Default Credentials.
For more information, see

[Set up authentication for client libraries](https://docs.cloud.google.com/bigquery/docs/authentication#client-libs).


    from google.cloud import https://docs.cloud.google.com/python/docs/reference/bigquery/latest

    # Construct a BigQuery client object.
    client = https://docs.cloud.google.com/python/docs/reference/bigquery/latest.https://docs.cloud.google.com/python/docs/reference/bigquery/latest/google.cloud.bigquery.client.Client.html()

    # TODO(developer): Set the fully-qualified ID for the routine.
    # routine_id = "my-project.my_dataset.my_routine"

    routine = client.https://docs.cloud.google.com/python/docs/reference/bigquery/latest/google.cloud.bigquery.client.Client.html#google_cloud_bigquery_client_Client_get_routine(routine_id)

    routine.https://docs.cloud.google.com/python/docs/reference/bigquery/latest/google.cloud.bigquery.routine.Routine.html#google_cloud_bigquery_routine_Routine_body = "x * 4"

    routine = client.https://docs.cloud.google.com/python/docs/reference/bigquery/latest/google.cloud.bigquery.client.Client.html#google_cloud_bigquery_client_Client_update_routine(
        routine,
        [
            "body",
            # Due to a limitation of the API,
            # all fields are required, not just
            # those that have been updated.
            "arguments",
            "language",
            "type_",
            "return_type",
        ],
    )  # Make an API request.

## What's next


To search and filter code samples for other Google Cloud products, see the
[Google Cloud sample browser](https://docs.cloud.google.com/docs/samples?product=bigquery).