List tasks

A Batch job consists of one or several tasks. This sample retrieves the name and current state of all tasks in a given job.

Explore further

For detailed documentation that includes this code sample, see the following:

Code sample

C++

For more information, see the Batch C++ API reference documentation.

To authenticate to Batch, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

#include "google/cloud/batch/v1/batch_client.h"

  [](std::string const& project_id, std::string const& location_id,
     std::string const& job_id, std::string const& group_id) {
    auto const parent = "projects/" + project_id + "/locations/" + location_id +
                        "/jobs/" + job_id + "/taskGroups/" + group_id;
    // Initialize a client and issue the request.
    auto client = google::cloud::batch_v1::BatchServiceClient(
        google::cloud::batch_v1::MakeBatchServiceConnection());
    int i = 0;
    for (auto task : client.ListTasks(parent)) {
      if (!task) throw std::move(task).status();
      std::cout << "Task[" << i++ << "]  " << task->DebugString() << "\n";
    }
  }

Go

For more information, see the Batch Go API reference documentation.

To authenticate to Batch, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

import (
	"context"
	"fmt"
	"io"

	batch "cloud.google.com/go/batch/apiv1"
	"cloud.google.com/go/batch/apiv1/batchpb"
	"google.golang.org/api/iterator"
)

// Lists all tasks in the given project and region
func listTasks(w io.Writer, projectID, region, jobName, taskGroup string) error {
	// projectID := "your_project_id"
	// region := "us-central1"
	// jobName := "some-job"
	// taskGroup := "group0" // defaults to "group0" on job creation unless overridden

	ctx := context.Background()
	batchClient, err := batch.NewClient(ctx)
	if err != nil {
		return fmt.Errorf("NewClient: %w", err)
	}
	defer batchClient.Close()

	req := &batchpb.ListTasksRequest{
		Parent: fmt.Sprintf("projects/%s/locations/%s/jobs/%s/taskGroups/%s", projectID, region, jobName, taskGroup),
	}

	var tasks []*batchpb.Task
	it := batchClient.ListTasks(ctx, req)

	for {
		task, err := it.Next()
		if err == iterator.Done {
			break
		}
		if err != nil {
			return fmt.Errorf("unable to list tasks: %w", err)
		}
		tasks = append(tasks, task)
	}

	fmt.Fprintf(w, "Tasks: %v\n", tasks)

	return nil
}

Java

For more information, see the Batch Java API reference documentation.

To authenticate to Batch, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

import com.google.cloud.batch.v1.BatchServiceClient;
import com.google.cloud.batch.v1.Task;
import java.io.IOException;

public class ListTasks {

  public static void main(String[] args) throws IOException {
    // TODO(developer): Replace these variables before running the sample.
    // Project ID or project number of the Cloud project you want to use.
    String projectId = "YOUR_PROJECT_ID";
    // Name of the region hosts the job.
    String region = "europe-central2";
    // Name of the job which tasks you want to list.
    String jobName = "JOB_NAME";
    // Name of the group of tasks. Usually it's `group0`.
    String groupName = "group0";

    listTasks(projectId, region, jobName, groupName);
  }

  // Get a list of all jobs defined in given region.
  public static void listTasks(String projectId, String region, String jobName, String groupName)
      throws IOException {
    // Initialize client that will be used to send requests. This client only needs to be created
    // once, and can be reused for multiple requests. After completing all of your requests, call
    // the `batchServiceClient.close()` method on the client to safely
    // clean up any remaining background resources.
    try (BatchServiceClient batchServiceClient = BatchServiceClient.create()) {

      String parent = String.format("projects/%s/locations/%s/jobs/%s/taskGroups/%s", projectId,
          region, jobName, groupName);
      for (Task task : batchServiceClient.listTasks(parent).iterateAll()) {
        System.out.println(task.getName());
      }
    }
  }
}

Node.js

For more information, see the Batch Node.js API reference documentation.

To authenticate to Batch, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

/**
 * TODO(developer): Uncomment and replace these variables before running the sample.
 */
// const projectId = 'YOUR_PROJECT_ID';
/**
 * The region that hosts the job.
 */
// const region = 'us-central-1';
/**
 * The name of the job which tasks you want to list.
 */
// const jobName = 'YOUR_JOB_NAME';
/**
 * The name of the group of tasks. Usually it's `group0`.
 */
// const groupName = 'group0';

// Imports the Batch library
const batchLib = require('@google-cloud/batch');

// Instantiates a client
const batchClient = new batchLib.v1.BatchServiceClient();

async function callListTasks() {
  // Construct request
  const request = {
    parent: `projects/${projectId}/locations/${region}/jobs/${jobName}/taskGroups/${groupName}`,
  };

  // Run request
  const iterable = await batchClient.listTasksAsync(request);
  for await (const response of iterable) {
    console.log(response);
  }
}

await callListTasks();

Python

For more information, see the Batch Python API reference documentation.

To authenticate to Batch, set up Application Default Credentials. For more information, see Set up authentication for a local development environment. 

from __future__ import annotations

from collections.abc import Iterable

from google.cloud import batch_v1


def list_tasks(
    project_id: str, region: str, job_name: str, group_name: str
) -> Iterable[batch_v1.Task]:
    """
    Get a list of all jobs defined in given region.

    Args:
        project_id: project ID or project number of the Cloud project you want to use.
        region: name of the region hosting the jobs.
        job_name: name of the job which tasks you want to list.
        group_name: name of the group of tasks. Usually it's `group0`.

    Returns:
        An iterable collection of Task objects.
    """
    client = batch_v1.BatchServiceClient()

    return client.list_tasks(
        parent=f"projects/{project_id}/locations/{region}/jobs/{job_name}/taskGroups/{group_name}"
    )

What's next

To search and filter code samples for other Google Cloud products, see the Google Cloud sample browser.