Set an event-based hold on an object

An example of how to set an event-based hold on an object.

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

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& object_name) {
  StatusOr<gcs::ObjectMetadata> original =
      client.GetObjectMetadata(bucket_name, object_name);
  if (!original) throw std::move(original).status();

  StatusOr<gcs::ObjectMetadata> updated = client.PatchObject(
      bucket_name, object_name,
      gcs::ObjectMetadataPatchBuilder().SetEventBasedHold(true),
      gcs::IfMetagenerationMatch(original->metageneration()));
  if (!updated) throw std::move(updated).status();

  std::cout << "The event hold for object " << updated->name()
            << " in bucket " << updated->bucket() << " is "
            << (updated->event_based_hold() ? "enabled" : "disabled") << "\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.Cloud.Storage.V1;
using System;

public class SetEventBasedHoldSample
{
    public void SetEventBasedHold(
        string bucketName = "your-unique-bucket-name",
        string objectName = "your-object-name")
    {
        var storage = StorageClient.Create();
        var storageObject = storage.GetObject(bucketName, objectName);
        storageObject.EventBasedHold = true;
        storage.UpdateObject(storageObject);
        Console.WriteLine($"Event-based hold was set for {objectName}.");
    }
}

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"
	"time"

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

// setEventBasedHold sets EventBasedHold flag of an object to true.
func setEventBasedHold(w io.Writer, bucket, object string) error {
	// bucket := "bucket-name"
	// object := "object-name"
	ctx := context.Background()
	client, err := storage.NewClient(ctx)
	if err != nil {
		return fmt.Errorf("storage.NewClient: %w", err)
	}
	defer client.Close()

	ctx, cancel := context.WithTimeout(ctx, time.Second*10)
	defer cancel()

	o := client.Bucket(bucket).Object(object)

	// Optional: set a metageneration-match precondition to avoid potential race
	// conditions and data corruptions. The request to update is aborted if the
	// object's metageneration does not match your precondition.
	attrs, err := o.Attrs(ctx)
	if err != nil {
		return fmt.Errorf("object.Attrs: %w", err)
	}
	o = o.If(storage.Conditions{MetagenerationMatch: attrs.Metageneration})

	// Update the object to add the object hold.
	objectAttrsToUpdate := storage.ObjectAttrsToUpdate{
		EventBasedHold: true,
	}
	if _, err := o.Update(ctx, objectAttrsToUpdate); err != nil {
		return fmt.Errorf("Object(%q).Update: %w", object, err)
	}
	fmt.Fprintf(w, "Default event based hold was enabled for %v.\n", object)
	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.Blob;
import com.google.cloud.storage.BlobId;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageException;
import com.google.cloud.storage.StorageOptions;

public class SetEventBasedHold {
  public static void setEventBasedHold(String projectId, String bucketName, String objectName)
      throws StorageException {
    // The ID of your GCP project
    // String projectId = "your-project-id";

    // The ID of your GCS bucket
    // String bucketName = "your-unique-bucket-name";

    // The ID of your GCS object
    // String objectName = "your-object-name";

    Storage storage = StorageOptions.newBuilder().setProjectId(projectId).build().getService();
    BlobId blobId = BlobId.of(bucketName, objectName);
    Blob blob = storage.get(blobId);
    if (blob == null) {
      System.out.println("The object " + objectName + " was not found in " + bucketName);
      return;
    }

    // Optional: set a generation-match precondition to avoid potential race
    // conditions and data corruptions. The request to upload returns a 412 error if
    // the object's generation number does not match your precondition.
    Storage.BlobTargetOption precondition = Storage.BlobTargetOption.generationMatch();

    blob.toBuilder().setEventBasedHold(true).build().update(precondition);

    System.out.println("Event-based hold was set for " + objectName);
  }
}

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 your GCS file
// const fileName = 'your-file-name';

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

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

async function setEventBasedHold() {
  // Optional: set a meta-generation-match precondition to avoid potential race
  // conditions and data corruptions. The request to set metadata is aborted if the
  // object's metageneration number does not match your precondition.
  const options = {
    ifMetagenerationMatch: metagenerationMatchPrecondition,
  };

  // Set event-based hold
  await storage.bucket(bucketName).file(fileName).setMetadata(
    {
      eventBasedHold: true,
    },
    options
  );
  console.log(`Event-based hold was set for ${fileName}.`);
}

setEventBasedHold().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;

/**
 * Sets an event-based hold for an object.
 *
 * @param string $bucketName The name of your Cloud Storage bucket.
 *        (e.g. 'my-bucket')
 * @param string $objectName The name of your Cloud Storage object.
 *        (e.g. 'my-object')
 */
function set_event_based_hold(string $bucketName, string $objectName): void
{
    $storage = new StorageClient();
    $bucket = $storage->bucket($bucketName);
    $object = $bucket->object($objectName);
    $object->update(['eventBasedHold' => true]);
    printf('Event-based hold was set for %s' . PHP_EOL, $objectName);
}

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 set_event_based_hold(bucket_name, blob_name):
    """Sets a event based hold on a given blob"""
    # bucket_name = "my-bucket"
    # blob_name = "my-blob"

    storage_client = storage.Client()
    bucket = storage_client.bucket(bucket_name)
    blob = bucket.blob(blob_name)
    metageneration_match_precondition = None

    # Optional: set a metageneration-match precondition to avoid potential race
    # conditions and data corruptions. The request to patch is aborted if the
    # object's metageneration does not match your precondition.
    blob.reload()  # Fetch blob metadata to use in metageneration_match_precondition.
    metageneration_match_precondition = blob.metageneration

    blob.event_based_hold = True
    blob.patch(if_metageneration_match=metageneration_match_precondition)

    print(f"Event based hold was set for {blob_name}")

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.

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

  # The ID of your GCS object
  # file_name = "your-file-name"

  require "google/cloud/storage"

  storage = Google::Cloud::Storage.new
  bucket  = storage.bucket bucket_name, skip_lookup: true
  file    = bucket.file file_name

  file.set_event_based_hold!

  puts "Event-based hold was set for #{file_name}."
end

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