在附加时刷新门户/存储资源管理器时，Azure Blob 存储附加 blob 409/修改错误

Question

我在将 block 上传到 Azure 中的追加 blob 时收到错误。单独处理时，该过程工作正常，但当我使用存储资源管理器(最新版本)刷新容器或在上传时刷新 Azure 门户中的页面时，问题就出现了。我的过程抛出以下内容。

An exception of type 'Azure.RequestFailedException' occurred in System.Private.CoreLib.dll but was not handled in user code: 'The blob has been modified while being read.
RequestId:62778adb-001e-011e-29a4-d589bf000000
Time:2021-11-09T20:02:29.3183234Z
Status: 409 (The blob has been modified while being read.)
ErrorCode: BlobModifiedWhileReading

租用文件没有什么区别。

测试代码为

using System;
using System.IO;
using System.Buffers;
using System.Threading.Tasks;
using Azure.Storage.Blobs;
using System.Text;
using Azure.Storage.Blobs.Specialized;

namespace str
{
    static class Program
    {
        static async Task Main(string[] args)
        {
            const string ContainerName = "files";
            const string BlobName = "my.blob";
            const int ChunkSize = 4194304; // 4MB

            const string connstr = "some-connecting-string-to-your-datalake-gen-2-account";
            
            BlobServiceClient blobClient = new(connstr);

            BlobContainerClient containerClient = blobClient.GetBlobContainerClient(ContainerName);
            await containerClient.CreateIfNotExistsAsync();

            AppendBlobClient appendClient = containerClient.GetAppendBlobClient(BlobName);
            await appendClient.CreateIfNotExistsAsync();

            using FileStream fs = await FileMaker.CreateNonsenseFileAsync();
            using BinaryReader reader = new(fs);

            bool readLoop = true;

            while (readLoop)
            {
                byte[] chunk = reader.ReadBytes(ChunkSize);

                if (chunk.Length > 0)
                    await appendClient.AppendBlockAsync(new MemoryStream(chunk));

                readLoop = chunk.Length == ChunkSize;
            }

            fs.Close();
            File.Delete(fs.Name);
        }
    }

    public static class FileMaker
    {
        public static async Task<FileStream> CreateNonsenseFileAsync(int blocks = 30000)
        {
            string tempFile = Path.GetTempFileName();
            FileStream fs = File.OpenWrite(tempFile);
            byte[] buffer = ArrayPool<byte>.Shared.Rent(1024);

            Random randy = new();

            using (StreamWriter writer = new(fs))
            {
                for (int i = 0; i < blocks; i++)
                {
                    randy.NextBytes(buffer);
                    await writer.WriteAsync(Encoding.UTF8.GetString(buffer));
                }
            }

            return File.OpenRead(tempFile);
        }
    }
}

csproj 是

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net5.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Azure.Storage.Files.DataLake" Version="12.8.0" />
    <PackageReference Include="System.Buffers" Version="4.5.1" />
  </ItemGroup>

</Project>

我只能想象刷新页面的行为会以某种方式触发元数据更改，并且服务会热情地放弃，但看起来相当随意，因为您可能不知道在上传到 blob 存储时谁在查看它？

如上所述，在没有人刷新门户或存储资源管理器中的页面的情况下，此代码可以正常工作并以 4MB block 上传垃圾(附加 blob 写入的限制，切换到 2MB block 不会产生任何影响)，而无需一个问题。

Answer 1

我尝试在我的系统中重现该场景，但没有遇到您所面临的问题。刷新门户后即可获取附加数据。

输出

刷新 blob 之前

刷新 blob 后