Télécharger tous les objets d'un bucket

Utilisez Transfer Manager pour télécharger tous les fichiers d'un bucket en profitant de la simultanéité.

En savoir plus

Pour obtenir une documentation détaillée incluant cet exemple de code, consultez la page suivante :

Télécharger des objets

Exemple de code

Java

Pour en savoir plus, consultez la documentation de référence de l'API Cloud Storage en langage Java.

Pour vous authentifier auprès de Cloud Storage, configurez le service Identifiants par défaut de l'application. Pour en savoir plus, consultez Configurer l'authentification pour un environnement de développement local.

import com.google.cloud.storage.BlobInfo;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageOptions;
import com.google.cloud.storage.transfermanager.DownloadResult;
import com.google.cloud.storage.transfermanager.ParallelDownloadConfig;
import com.google.cloud.storage.transfermanager.TransferManager;
import com.google.cloud.storage.transfermanager.TransferManagerConfig;
import java.nio.file.Path;
import java.util.List;
import java.util.stream.Collectors;

class DownloadBucket {

  public static void downloadBucketContents(
      String projectId, String bucketName, Path destinationDirectory) {
    Storage storage = StorageOptions.newBuilder().setProjectId(projectId).build().getService();
    List<BlobInfo> blobs =
        storage
            .list(bucketName)
            .streamAll()
            .map(blob -> blob.asBlobInfo())
            .collect(Collectors.toList());
    TransferManager transferManager = TransferManagerConfig.newBuilder().build().getService();
    ParallelDownloadConfig parallelDownloadConfig =
        ParallelDownloadConfig.newBuilder()
            .setBucketName(bucketName)
            .setDownloadDirectory(destinationDirectory)
            .build();

    List<DownloadResult> results =
        transferManager.downloadBlobs(blobs, parallelDownloadConfig).getDownloadResults();

    for (DownloadResult result : results) {
      System.out.println(
          "Download of "
              + result.getInput().getName()
              + " completed with status "
              + result.getStatus());
    }
  }
}

Python

Pour en savoir plus, consultez la documentation de référence de l'API Cloud Storage en langage Python.

def download_bucket_with_transfer_manager(
    bucket_name, destination_directory="", workers=8, max_results=1000
):
    """Download all of the blobs in a bucket, concurrently in a process pool.

    The filename of each blob once downloaded is derived from the blob name and
    the `destination_directory `parameter. For complete control of the filename
    of each blob, use transfer_manager.download_many() instead.

    Directories will be created automatically as needed, for instance to
    accommodate blob names that include slashes.
    """

    # The ID of your GCS bucket
    # bucket_name = "your-bucket-name"

    # The directory on your computer to which to download all of the files. This
    # string is prepended (with os.path.join()) to the name of each blob to form
    # the full path. Relative paths and absolute paths are both accepted. An
    # empty string means "the current working directory". Note that this
    # parameter allows accepts directory traversal ("../" etc.) and is not
    # intended for unsanitized end user input.
    # destination_directory = ""

    # The maximum number of processes to use for the operation. The performance
    # impact of this value depends on the use case, but smaller files usually
    # benefit from a higher number of processes. Each additional process occupies
    # some CPU and memory resources until finished. Threads can be used instead
    # of processes by passing `worker_type=transfer_manager.THREAD`.
    # workers=8

    # The maximum number of results to fetch from bucket.list_blobs(). This
    # sample code fetches all of the blobs up to max_results and queues them all
    # for download at once. Though they will still be executed in batches up to
    # the processes limit, queueing them all at once can be taxing on system
    # memory if buckets are very large. Adjust max_results as needed for your
    # system environment, or set it to None if you are sure the bucket is not
    # too large to hold in memory easily.
    # max_results=1000

    from google.cloud.storage import Client, transfer_manager

    storage_client = Client()
    bucket = storage_client.bucket(bucket_name)

    blob_names = [blob.name for blob in bucket.list_blobs(max_results=max_results)]

    results = transfer_manager.download_many_to_path(
        bucket, blob_names, destination_directory=destination_directory, max_workers=workers
    )

    for name, result in zip(blob_names, results):
        # The results list is either `None` or an exception for each blob in
        # the input list, in order.

        if isinstance(result, Exception):
            print("Failed to download {} due to exception: {}".format(name, result))
        else:
            print("Downloaded {} to {}.".format(name, destination_directory + name))

Étapes suivantes

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