在旧的1.7存储客户端中,有一个CloudBlob.CopyFromBlob(otherBlob)方法,但在2.0版本中似乎不存在。复制blob的推荐最佳实践是什么?我看到了ICloudBlob.BeginStartCopyFromBlob方法。如果那是合适的方法,我该如何使用它?
在旧的1.7存储客户端中,有一个CloudBlob.CopyFromBlob(otherBlob)方法,但在2.0版本中似乎不存在。复制blob的推荐最佳实践是什么?我看到了ICloudBlob.BeginStartCopyFromBlob方法。如果那是合适的方法,我该如何使用它?
Gaurav Mantri在Azure Storage 2.0上写了一系列文章。我从他的博客文章 - 存储客户端库 2.0 - 迁移 Blob 存储代码中提取了此代码片段,用于 Blob 复制。
CloudStorageAccount storageAccount = new CloudStorageAccount(new StorageCredentials(accountName, accountKey), true);
CloudBlobClient cloudBlobClient = storageAccount.CreateCloudBlobClient();
CloudBlobContainer sourceContainer = cloudBlobClient.GetContainerReference(containerName);
CloudBlobContainer targetContainer = cloudBlobClient.GetContainerReference(targetContainerName);
string blobName = "<Blob Name e.g. myblob.txt>";
CloudBlockBlob sourceBlob = sourceContainer.GetBlockBlobReference(blobName);
CloudBlockBlob targetBlob = targetContainer.GetBlockBlobReference(blobName);
targetBlob.StartCopyFromBlob(sourceBlob);
使用 Storage 6.3(比原问题中的库要新得多)和异步方法,使用 StartCopyAsync (MSDN)
CloudStorageAccount storageAccount = CloudStorageAccount.Parse("Your Connection");
CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
CloudBlobContainer container = blobClient.GetContainerReference("YourContainer");
CloudBlockBlob source = container.GetBlockBlobReference("Your Blob");
CloudBlockBlob target = container.GetBlockBlobReference("Your New Blob");
await target.StartCopyAsync(source);
最新版本(7.x)的SDK
中有关的内容FYI,此方法已不再适用,因为函数BeginStartCopyBlob
已不存在。
您可以尝试以下方式:
// this tunnels the data via your program,
// so it reuploads the blob instead of copying it on service side
using (var stream = await sourceBlob.OpenReadAsync())
{
await destinationBlob.UploadFromStreamAsync(stream);
}
正如@(Alexey Shcherbak)所提到的那样,这是一个更好的操作方式:
await targetCloudBlob.StartCopyAsync(sourceCloudBlob.Uri);
while (targetCloudBlob.CopyState.Status == CopyStatus.Pending)
{
await Task.Delay(500);
// Need to fetch or "CopyState" will never update
await targetCloudBlob.FetchAttributesAsync();
}
if (targetCloudBlob.CopyState.Status != CopyStatus.Success)
{
throw new Exception("Copy failed: " + targetCloudBlob.CopyState.Status);
}
从Azure Storage 8开始,要在存储账户之间移动Blob,我使用类似下面的代码,希望能帮到某些人:
//copy blobs - from
CloudStorageAccount sourceStorageAccount = new CloudStorageAccount(new StorageCredentials(storageFromName, storageFromKey), true);
CloudBlobClient sourceCloudBlobClient = sourceStorageAccount.CreateCloudBlobClient();
CloudBlobContainer sourceContainer = sourceCloudBlobClient.GetContainerReference(containerFromName);
//copy blobs - to
CloudStorageAccount targetStorageAccount = new CloudStorageAccount(new StorageCredentials(storageToName, storageToKey), true);
CloudBlobClient targetCloudBlobClient = targetStorageAccount.CreateCloudBlobClient();
CloudBlobContainer targetContainer = targetCloudBlobClient.GetContainerReference(containerToName);
//create target container if didn't exists
try{
await targetContainer.CreateIfNotExistsAsync();
}
catch(Exception e){
log.Error(e.Message);
}
CloudBlockBlob sourceBlob = sourceContainer.GetBlockBlobReference(blobName);
CloudBlockBlob targetBlob = targetContainer.GetBlockBlobReference(blobName);
try{
//initialize copying
await targetBlob.StartCopyAsync(sourceBlob.Uri);
}
catch(Exception ex){
log.Error(ex.Message);
//return error, in my case HTTP
return req.CreateResponse(HttpStatusCode.BadRequest, "Error, source BLOB probably has private access only: " +ex.Message);
}
//fetch current attributes
targetBlob.FetchAttributes();
//waiting for completion
while (targetBlob.CopyState.Status == CopyStatus.Pending){
log.Info("Status: " + targetBlob.CopyState.Status);
Thread.Sleep(500);
targetBlob.FetchAttributes();
}
//check status
if (targetBlob.CopyState.Status != CopyStatus.Success){
//return error, in my case HTTP
return req.CreateResponse(HttpStatusCode.BadRequest, "Copy failed with status: " + targetBlob.CopyState.Status);
}
//finally remove source in case Copy Status was Success
sourceBlob.Delete();
//and return success (in my case HTTP)
return req.CreateResponse(HttpStatusCode.OK, "Done.");
Naveen已经解释了正确使用StartCopyFromBlob
(同步方法)的语法。您提到的方法(BeginStartCopyFromBlob
)是可与Task
结合使用的异步替代方法,例如:
var blobClient = account.CreateCloudBlobClient();
// Upload picture.
var picturesContainer = blobClient.GetContainerReference("pictures");
picturesContainer.CreateIfNotExists();
var myPictureBlob = picturesContainer.GetBlockBlobReference("me.png");
using (var fs = new FileStream(@"C:\Users\Public\Pictures\Sample Pictures\Chrysanthemum.jpg", FileMode.Open))
myPictureBlob.UploadFromStream(fs);
// Backup picture.
var backupContainer = blobClient.GetContainerReference("backup");
backupContainer.CreateIfNotExists();
var backupBlob = picturesContainer.GetBlockBlobReference("me.png");
var task = Task.Factory.FromAsync<string>(backupBlob.BeginStartCopyFromBlob(myPictureBlob, null, null), backupBlob.EndStartCopyFromBlob);
task.ContinueWith((t) =>
{
if (!t.IsFaulted)
{
while (true)
{
Console.WriteLine("Copy state for {0}: {1}", backupBlob.Uri, backupBlob.CopyState.Status);
Thread.Sleep(500);
}
}
else
{
Console.WriteLine("Error: " + t.Exception);
}
});
看起来自从之前的文章发布以来,该API可能已有所清理。
// _client is a BlobServiceClient injected via DI in the constructor.
BlobContainerClient sourceContainerClient = _client.GetBlobContainerClient(sourceContainerName);
BlobClient sourceClient = sourceContainerClient.GetBlobClient(blobName);
BlobContainerClient destContainerClient = _client.GetBlobContainerClient(destContainerName);
BlobClient destClient = destContainerClient.GetBlobClient(blobName);
// assume that if the following doesn't throw an exception, then it is successful.
CopyFromUriOperation operation = await destClient.StartCopyFromUriAsync(sourceClient.Uri);
await operation.WaitForCompletionAsync();
operation.WaitForCompletionAsync
的文档说明:定期调用服务器,直到长时间运行的操作完成。该方法将周期性地调用UpdateStatusAsync直到HasCompleted为true,然后返回操作的最终结果。
查看此方法的源代码似乎调用了BlobBaseClient.GetProperties
(或其异步版本),如果出现错误将抛出RequestFailureException
异常。
对于我来说,WindowsAzure.Storage 8.0.1版本和James Hancock的解决方案在服务器端完成了复制,但客户端复制状态一直停留在Pending
(无限循环)。 解决方案是在Thread.sleep(500)
后在targetCloudBlob
上调用FetchAttributes()
。
// Aaron Sherman's code
targetCloudBlob.StartCopy(sourceCloudBlob.Uri);
while (targetCloudBlob.CopyState.Status == CopyStatus.Pending)
{
Thread.Sleep(500);
targetCloudBlob.FetchAttributes();
}
// James Hancock's remaining code
这是我的简短简单回答。
public void Copy(CloudBlockBlob srcBlob, CloudBlobContainer destContainer)
{
CloudBlockBlob destBlob;
if (srcBlob == null)
{
throw new Exception("Source blob cannot be null.");
}
if (!destContainer.Exists())
{
throw new Exception("Destination container does not exist.");
}
//Copy source blob to destination container
string name = srcBlob.Uri.Segments.Last();
destBlob = destContainer.GetBlockBlobReference(name);
destBlob.StartCopyAsync(srcBlob);
}