Get a Pub/Sub notification

Provides an example of how to get Pub/Sub notification metadata.

Explore further

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

• Configure Pub/Sub notifications for Cloud Storage

Code sample

C++

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

namespace gcs = ::google::cloud::storage;
using ::google::cloud::StatusOr;
[](gcs::Client client, std::string const& bucket_name,
   std::string const& notification_id) {
  StatusOr<gcs::NotificationMetadata> notification =
      client.GetNotification(bucket_name, notification_id);
  if (!notification) throw std::move(notification).status();

  std::cout << "Notification " << notification->id() << " for bucket "
            << bucket_name << "\n";
  if (notification->object_name_prefix().empty()) {
    std::cout << "This notification is sent for all objects in the bucket\n";
  } else {
    std::cout << "This notification is sent only for objects starting with"
              << " the prefix " << notification->object_name_prefix() << "\n";
  }
  std::cout << "Full details for the notification:\n"
            << *notification << "\n";
}

C#

For more information, see the Cloud Storage C# API reference documentation.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

using Google.Apis.Storage.v1.Data;
using Google.Cloud.Storage.V1;
using System;

public class GetPubSubNotificationSample
{
    public Notification GetPubSubNotification(
        string bucketName = "your-unique-bucket-name",
        string notificationId = "notificationId")
    {
        StorageClient storage = StorageClient.Create();
        Notification notification = storage.GetNotification(bucketName, notificationId);

        Console.WriteLine("ID: " + notification.Id);
        Console.WriteLine("Topic: " + notification.Topic);
        Console.WriteLine("EventTypes: " + notification.EventTypes);
        Console.WriteLine("CustomAttributes: " + notification.CustomAttributes);
        Console.WriteLine("PayloadFormat: " + notification.PayloadFormat);
        Console.WriteLine("ObjectNamePrefix: " + notification.ObjectNamePrefix);
        Console.WriteLine("ETag: " + notification.ETag);
        Console.WriteLine("SelfLink: " + notification.SelfLink);
        Console.WriteLine("Kind: " + notification.Kind);

        return notification;
    }
}

Go

For more information, see the Cloud Storage Go API reference documentation.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

import (
	"context"
	"fmt"
	"io"

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

// printPubsubBucketNotification gets a notification configuration for a bucket.
func printPubsubBucketNotification(w io.Writer, bucketName, notificationID string) error {
	// bucketName := "bucket-name"
	// notificationID := "notification-id"

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

	notifications, err := client.Bucket(bucketName).Notifications(ctx)
	if err != nil {
		return fmt.Errorf("Bucket.Notifications: %w", err)
	}

	n := notifications[notificationID]
	fmt.Fprintf(w, "Notification: %+v", n)

	return nil
}

Java

For more information, see the Cloud Storage Java API reference documentation.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

import com.google.cloud.storage.Notification;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageOptions;

public class PrintPubSubNotification {

  public static void printPubSubNotification(String bucketName, String notificationId) {
    // The ID to give your GCS bucket
    // String bucketName = "your-unique-bucket-name";

    // The Pub/Sub topic you would like to find
    // String notificationId = "your-unique-notification-id"

    Storage storage = StorageOptions.newBuilder().build().getService();
    Notification notification = storage.getNotification(bucketName, notificationId);
    System.out.println(
        "Found notification " + notification.getTopic() + " for bucket " + bucketName);
  }
}

Node.js

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

/**
 * TODO(developer): Uncomment the following lines before running the sample.
 */
// The ID of your GCS bucket
// const bucketName = 'your-unique-bucket-name';

// The ID of the notification
// const notificationId = '1';

// Imports the Google Cloud client library
const {Storage} = require('@google-cloud/storage');

// Creates a client
const storage = new Storage();

async function getMetadata() {
  // Get the notification metadata
  const [metadata] = await storage
    .bucket(bucketName)
    .notification(notificationId)
    .getMetadata();

  console.log(`ID: ${metadata.id}`);
  console.log(`Topic: ${metadata.topic}`);
  console.log(`Event Types: ${metadata.event_types}`);
  console.log(`Custom Attributes: ${metadata.custom_attributes}`);
  console.log(`Payload Format: ${metadata.payload_format}`);
  console.log(`Object Name Prefix: ${metadata.object_name_prefix}`);
  console.log(`Etag: ${metadata.etag}`);
  console.log(`Self Link: ${metadata.selfLink}`);
  console.log(`Kind: ${metadata.kind}`);
}

getMetadata().catch(console.error);

PHP

For more information, see the Cloud Storage PHP API reference documentation.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

use Google\Cloud\Storage\StorageClient;

/**
 * Lists notification configurations for a bucket.
 * This sample is used on this page:
 *   https://cloud.google.com/storage/docs/reporting-changes
 *
 * @param string $bucketName The name of your Cloud Storage bucket.
 *        (e.g. 'your-bucket')
 * @param string $notificationId The ID of the notification.
 *        (e.g. 'your-notification-id')
 */
function print_pubsub_bucket_notification(
    string $bucketName,
    string $notificationId
): void {
    $storage = new StorageClient();
    $bucket = $storage->bucket($bucketName);
    $notification = $bucket->notification($notificationId);
    $notificationInfo = $notification->info();

    printf(
        <<<EOF
Notification ID: %s
Topic Name: %s
Event Types: %s
Custom Attributes: %s
Payload Format: %s
Blob Name Prefix: %s
Etag: %s
Self Link: %s
EOF . PHP_EOL,
        $notification->id(),
        $notificationInfo['topic'],
        $notificationInfo['event_types'] ?? '',
        $notificationInfo['custom_attributes'] ?? '',
        $notificationInfo['payload_format'],
        $notificationInfo['blob_name_prefix'] ?? '',
        $notificationInfo['etag'],
        $notificationInfo['selfLink']
    );
}

Python

For more information, see the Cloud Storage Python API reference documentation.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

from google.cloud import storage


def print_pubsub_bucket_notification(bucket_name, notification_id):
    """Gets a notification configuration for a bucket."""
    # The ID of your GCS bucket
    # bucket_name = "your-bucket-name"
    # The ID of the notification
    # notification_id = "your-notification-id"

    storage_client = storage.Client()
    bucket = storage_client.bucket(bucket_name)
    notification = bucket.get_notification(notification_id)

    print(f"Notification ID: {notification.notification_id}")
    print(f"Topic Name: {notification.topic_name}")
    print(f"Event Types: {notification.event_types}")
    print(f"Custom Attributes: {notification.custom_attributes}")
    print(f"Payload Format: {notification.payload_format}")
    print(f"Blob Name Prefix: {notification.blob_name_prefix}")
    print(f"Etag: {notification.etag}")
    print(f"Self Link: {notification.self_link}")

Ruby

For more information, see the Cloud Storage Ruby API reference documentation.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

require "google/cloud/storage"

def print_pubsub_bucket_notification bucket_name:, notification_id:
  # The ID of your GCS bucket
  # bucket_name = "your-unique-bucket-name"

  # The ID of your notification configured for the bucket
  # notification_id = "your-notification-id"


  storage = Google::Cloud::Storage.new
  bucket  = storage.bucket bucket_name
  notification = bucket.notification notification_id

  puts "Notification ID: #{notification.id}"
  puts "Topic Name: #{notification.topic}"
  puts "Event Types: #{notification.event_types}"
  puts "Kind of Notification: #{notification.kind}"
  puts "Custom Attributes: #{notification.custom_attrs}"
  puts "Payload Format: #{notification.payload}"
  puts "Blob Name Prefix: #{notification.prefix}"
  puts "Self Link: #{notification.api_url}"
end

What's next

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