如何为可跨本地与Azure云部署的C#应用抽象存储层？

刚好我之前做过类似的跨环境存储适配需求，给你一套落地性很强的方案——核心就是用抽象层+依赖注入把存储逻辑和业务代码彻底解耦，完全不用让业务关心底层是本地SMB还是Azure文件共享：

先写一个通用的IFileStorage接口，涵盖业务需要的所有文件操作（比如创建目录、上传下载、列举文件等），业务层只依赖这个接口，完全不碰具体实现：

public interface IFileStorage
{
    Task CreateDirectoryAsync(string directoryPath, CancellationToken cancellationToken = default);
    Task UploadFileAsync(string localFilePath, string remoteFilePath, CancellationToken cancellationToken = default);
    Task DownloadFileAsync(string remoteFilePath, string localFilePath, CancellationToken cancellationToken = default);
    Task<IEnumerable<string>> ListFilesAsync(string directoryPath, CancellationToken cancellationToken = default);
    Task DeleteFileAsync(string remoteFilePath, CancellationToken cancellationToken = default);
}

针对本地SMB和Azure文件共享，各自写实现类，把复杂的配置和操作细节都封装在这里：

本地SMB实现 #

因为Linux容器挂载SMB共享后，路径和本地文件系统完全一致，直接用System.IO的API封装即可：

public class SmbFileStorage : IFileStorage
{
    private readonly string _baseSharePath;

    public SmbFileStorage(string baseSharePath)
    {
        _baseSharePath = baseSharePath;
    }

    public async Task CreateDirectoryAsync(string directoryPath, CancellationToken cancellationToken = default)
    {
        var fullPath = Path.Combine(_baseSharePath, directoryPath);
        await Task.Run(() => Directory.CreateDirectory(fullPath), cancellationToken);
    }

    public async Task UploadFileAsync(string localFilePath, string remoteFilePath, CancellationToken cancellationToken = default)
    {
        var fullRemotePath = Path.Combine(_baseSharePath, remoteFilePath);
        // 确保父目录存在
        await CreateDirectoryAsync(Path.GetDirectoryName(remoteFilePath)!, cancellationToken);
        await File.CopyAsync(localFilePath, fullRemotePath, overwrite: true, cancellationToken);
    }

    // 其他方法（下载、列举、删除）都类似，基于System.IO异步API封装即可
}

Azure文件共享实现 #

用官方的Azure.Storage.Files.Shares NuGet包，把Azure的存储操作封装成符合接口的实现：

public class AzureFileStorage : IFileStorage
{
    private readonly ShareClient _shareClient;

    public AzureFileStorage(string connectionString, string shareName)
    {
        _shareClient = new ShareClient(connectionString, shareName);
    }

    public async Task CreateDirectoryAsync(string directoryPath, CancellationToken cancellationToken = default)
    {
        var directoryClient = _shareClient.GetDirectoryClient(directoryPath);
        await directoryClient.CreateIfNotExistsAsync(cancellationToken: cancellationToken);
    }

    public async Task UploadFileAsync(string localFilePath, string remoteFilePath, CancellationToken cancellationToken = default)
    {
        // 先确保父目录存在
        await CreateDirectoryAsync(Path.GetDirectoryName(remoteFilePath)!, cancellationToken);
        
        var fileClient = _shareClient.GetFileClient(remoteFilePath);
        await using var fileStream = File.OpenRead(localFilePath);
        await fileClient.CreateAsync(fileStream.Length, cancellationToken: cancellationToken);
        await fileClient.UploadAsync(fileStream, cancellationToken: cancellationToken);
    }

    // 其他方法同样基于Azure SDK封装，对应接口定义
}

在appsettings.json里配置当前环境的存储类型和参数：

"FileStorageSettings": {
    "StorageType": "Azure", // 可选值：Azure/Smb
    "Azure": {
        "ConnectionString": "your-azure-storage-connection-string",
        "ShareName": "your-share-name"
    },
    "Smb": {
        "BaseSharePath": "/mnt/smb-share" // Linux容器中挂载的SMB共享路径
    }
}

然后在Program.cs里根据配置注册对应的服务：

var storageSettings = builder.Configuration.GetSection("FileStorageSettings").Get<FileStorageSettings>();

switch (storageSettings.StorageType.ToLower())
{
    case "azure":
        builder.Services.AddSingleton<IFileStorage>(_ => 
            new AzureFileStorage(storageSettings.Azure.ConnectionString, storageSettings.Azure.ShareName));
        break;
    case "smb":
        builder.Services.AddSingleton<IFileStorage>(_ => 
            new SmbFileStorage(storageSettings.Smb.BaseSharePath));
        break;
    default:
        throw new InvalidOperationException($"Unsupported storage type: {storageSettings.StorageType}");
}

业务代码只需要注入IFileStorage，完全不用关心底层是哪种存储：

public class DocumentService
{
    private readonly IFileStorage _fileStorage;

    public DocumentService(IFileStorage fileStorage)
    {
        _fileStorage = fileStorage;
    }

    public async Task UploadUserDocumentAsync(string localFilePath, string userId)
    {
        await _fileStorage.CreateDirectoryAsync($"user-docs/{userId}");
        await _fileStorage.UploadFileAsync(localFilePath, $"user-docs/{userId}/{Path.GetFileName(localFilePath)}");
    }
}

• Linux容器挂载SMB时，需要在容器启动配置里完成挂载（比如Docker的--mount参数，或者K8s的PersistentVolumeClaim），应用只需要用挂载后的路径即可。
• 如果想简化Azure部署的配置，也可以把Azure文件共享挂载到容器里，复用SMB的实现，但直接用Azure SDK能更好地利用Azure的原生特性（比如快照、权限控制）。
• 可以在实现类里统一处理异常，比如封装成自定义的FileStorageException，业务层只需要处理这一种异常即可。

内容的提问来源于stack exchange，提问作者Russ