Copy an archived object

Copy an archived generation of an object in a Cloud Storage bucket.

Explore further

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

• Use versioned objects

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& source_bucket_name,
   std::string const& source_object_name,
   std::string const& destination_bucket_name,
   std::string const& destination_object_name,
   std::int64_t source_object_generation) {
  StatusOr<gcs::ObjectMetadata> copy =
      client.CopyObject(source_bucket_name, source_object_name,
                        destination_bucket_name, destination_object_name,
                        gcs::SourceGeneration{source_object_generation});
  if (!copy) throw std::move(copy).status();

  std::cout << "Successfully copied " << source_object_name << " generation "
            << source_object_generation << " in bucket " << source_bucket_name
            << " to bucket " << copy->bucket() << " with name "
            << copy->name()
            << ".\nThe full metadata after the copy is: " << *copy << "\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 CopyFileArchivedGenerationSample
{
    public Google.Apis.Storage.v1.Data.Object CopyFileArchivedGeneration(
        string sourceBucketName = "source-bucket-name",
        string sourceObjectName = "source-file",
        string destBucketName = "destination-bucket-name",
        string destObjectName = "destination-file-name",
        long? generation = 1579287380533984)
    {
        var storage = StorageClient.Create();
        var copyOptions = new CopyObjectOptions
        {
            SourceGeneration = generation
        };

        var copiedFile = storage.CopyObject(sourceBucketName, sourceObjectName,
            destBucketName, destObjectName, copyOptions);

        Console.WriteLine($"Generation {generation} of the object {sourceBucketName}/{sourceObjectName} " +
            $"was copied to to {destBucketName}/{destObjectName}.");

        return copiedFile;
    }
}

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"
)

// copyOldVersionOfObject copies a noncurrent version of an object.
func copyOldVersionOfObject(w io.Writer, bucket, srcObject, dstObject string, gen int64) error {
	// bucket := "bucket-name"
	// srcObject := "source-object-name"
	// dstObject := "destination-object-name"

	// gen is the generation of srcObject to copy.
	// gen := 1587012235914578
	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()

	src := client.Bucket(bucket).Object(srcObject)
	dst := client.Bucket(bucket).Object(dstObject)

	// Optional: set a generation-match precondition to avoid potential race
	// conditions and data corruptions. The request to copy is aborted if the
	// object's generation number does not match your precondition.
	// For a dst object that does not yet exist, set the DoesNotExist precondition.
	dst = dst.If(storage.Conditions{DoesNotExist: true})
	// If the destination object already exists in your bucket, set instead a
	// generation-match precondition using its generation number.
	// attrs, err := dst.Attrs(ctx)
	// if err != nil {
	// 	return fmt.Errorf("object.Attrs: %w", err)
	// }
	// dst = dst.If(storage.Conditions{GenerationMatch: attrs.Generation})

	if _, err := dst.CopierFrom(src.Generation(gen)).Run(ctx); err != nil {
		return fmt.Errorf("Object(%q).CopierFrom(%q).Generation(%v).Run: %w", dstObject, srcObject, gen, err)
	}
	fmt.Fprintf(w, "Generation %v of object %v in bucket %v was copied to %v\n", gen, srcObject, bucket, dstObject)
	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.BlobId;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageOptions;

public class CopyOldVersionOfObject {
  public static void copyOldVersionOfObject(
      String projectId,
      String bucketName,
      String objectToCopy,
      long generationToCopy,
      String newObjectName) {
    // 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 the GCS object to copy an old version of
    // String objectToCopy = "your-object-name";

    // The generation of objectToCopy to copy
    // long generationToCopy = 1579287380533984;

    // What to name the new object with the old data from objectToCopy
    // String newObjectName = "your-new-object";

    Storage storage = StorageOptions.newBuilder().setProjectId(projectId).build().getService();

    // Optional: set a generation-match precondition to avoid potential race
    // conditions and data corruptions. The request returns a 412 error if the
    // preconditions are not met.
    Storage.BlobTargetOption precondition;
    if (storage.get(bucketName, newObjectName) == null) {
      // For a target object that does not yet exist, set the DoesNotExist precondition.
      // This will cause the request to fail if the object is created before the request runs.
      precondition = Storage.BlobTargetOption.doesNotExist();
    } else {
      // If the destination already exists in your bucket, instead set a generation-match
      // precondition. This will cause the request to fail if the existing object's generation
      // changes before the request runs.
      precondition =
          Storage.BlobTargetOption.generationMatch(
              storage.get(bucketName, newObjectName).getGeneration());
    }

    Storage.CopyRequest copyRequest =
        Storage.CopyRequest.newBuilder()
            .setSource(BlobId.of(bucketName, objectToCopy, generationToCopy))
            .setTarget(BlobId.of(bucketName, newObjectName), precondition)
            .build();
    storage.copy(copyRequest);

    System.out.println(
        "Generation "
            + generationToCopy
            + " of object "
            + objectToCopy
            + " in bucket "
            + bucketName
            + " was copied to "
            + newObjectName);
  }
}

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 srcBucketName = "your-unique-bucket-name";

// The ID of the GCS file to copy an old version of
// const srcFilename = "your-file-name";

// The generation of fileToCopy to copy
// const generation = 1579287380533984;

// The ID of the bucket to copy the file to
// const destBucketName = 'target-file-bucket';

// What to name the new file with the old data from srcFilename
// const destFileName = "your-new-file";

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

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

async function copyOldVersionOfFile() {
  // Copies the file to the other bucket

  // Optional:
  // Set a generation-match precondition to avoid potential race conditions
  // and data corruptions. The request to copy is aborted if the object's
  // generation number does not match your precondition. For a destination
  // object that does not yet exist, set the ifGenerationMatch precondition to 0
  // If the destination object already exists in your bucket, set instead a
  // generation-match precondition using its generation number.
  const copyOptions = {
    preconditionOpts: {
      ifGenerationMatch: destinationGenerationMatchPrecondition,
    },
  };

  await storage
    .bucket(srcBucketName)
    .file(srcFilename, {
      generation,
    })
    .copy(storage.bucket(destBucketName).file(destFileName), copyOptions);

  console.log(
    `Generation ${generation} of file ${srcFilename} in bucket ${srcBucketName} was copied to ${destFileName} in bucket ${destBucketName}`
  );
}

copyOldVersionOfFile().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;

/**
 * Copy archived generation of a given object to a new object.
 *
 * @param string $bucketName The name of your Cloud Storage bucket.
 *        (e.g. 'my-bucket')
 * @param string $objectToCopy The name of the object to copy.
 *        (e.g. 'my-object')
 * @param string $generationToCopy The generation of the object to copy.
 *        (e.g. 1579287380533984)
 * @param string $newObjectName The name of the target object.
 *        (e.g. 'my-object-1579287380533984')
 */
function copy_file_archived_generation(string $bucketName, string $objectToCopy, string $generationToCopy, string $newObjectName): void
{
    $storage = new StorageClient();
    $bucket = $storage->bucket($bucketName);

    $object = $bucket->object($objectToCopy, [
        'generation' => $generationToCopy,
    ]);

    $object->copy($bucket, [
        'name' => $newObjectName,
    ]);

    printf(
        'Generation %s of object %s in bucket %s was copied to %s',
        $generationToCopy,
        $objectToCopy,
        $bucketName,
        $newObjectName
    );
}

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 copy_file_archived_generation(
        bucket_name, blob_name, destination_bucket_name, destination_blob_name, generation
):
    """Copies a blob from one bucket to another with a new name with the same generation."""
    # bucket_name = "your-bucket-name"
    # blob_name = "your-object-name"
    # destination_bucket_name = "destination-bucket-name"
    # destination_blob_name = "destination-object-name"
    # generation = 1579287380533984

    storage_client = storage.Client()

    source_bucket = storage_client.bucket(bucket_name)
    source_blob = source_bucket.blob(blob_name)
    destination_bucket = storage_client.bucket(destination_bucket_name)

    # Optional: set a generation-match precondition to avoid potential race conditions
    # and data corruptions. The request to copy is aborted if the object's
    # generation number does not match your precondition. For a destination
    # object that does not yet exist, set the if_generation_match precondition to 0.
    # If the destination object already exists in your bucket, set instead a
    # generation-match precondition using its generation number.
    destination_generation_match_precondition = 0

    # source_generation selects a specific revision of the source object, as opposed to the latest version.
    blob_copy = source_bucket.copy_blob(
        source_blob, destination_bucket, destination_blob_name, source_generation=generation, if_generation_match=destination_generation_match_precondition
    )

    print(
        "Generation {} of the blob {} in bucket {} copied to blob {} in bucket {}.".format(
            generation,
            source_blob.name,
            source_bucket.name,
            blob_copy.name,
            destination_bucket.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 copy_file_archived_generation source_bucket_name:,
                                  source_file_name:,
                                  generation:,
                                  destination_bucket_name:,
                                  destination_file_name:
  # The ID of the bucket the original object is in
  # source_bucket_name = "source-bucket-name"

  # The ID of the GCS object to copy
  # source_file_name = "source-file-name"

  # The generation of your GCS object to copy
  # generation = 1579287380533984

  # The ID of the bucket to copy the object to
  # destination_bucket_name = "destination-bucket-name"

  # The ID of the new GCS object
  # destination_file_name = "destination-file-name"

  require "google/cloud/storage"

  storage = Google::Cloud::Storage.new

  source_bucket = storage.bucket source_bucket_name, skip_lookup: true
  source_file = source_bucket.file source_file_name
  destination_bucket = storage.bucket destination_bucket_name, skip_lookup: true

  destination_file = source_file.copy destination_bucket, destination_file_name, generation: generation

  puts "Generation #{generation} of the file #{source_file.name} in bucket #{source_bucket.name} copied to file " \
       "#{destination_file.name} in bucket #{destination_bucket.name}"
end

What's next

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