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Deepstaging

File Storage

File Storage¶

The File Storage module provides a standard interface for file and blob operations. Swap implementations via DI (Azure Blob, S3, local filesystem).

Quick Start¶

using Deepstaging.Effects;
using Deepstaging.Storage;

[EffectsModule(typeof(IFileStore))]
public sealed partial class StorageEffects;

[Runtime]
[Uses(typeof(StorageEffects))]
public sealed partial class AppRuntime;

The generator produces Eff<RT, A> wrappers for all six operations on IFileStore.

Effect Interface¶

`IFileStore`¶

Method	Returns	Description
`UploadAsync(key, content, contentType)`	`Task<FileMetadata>`	Upload a file to storage
`DownloadAsync(key)`	`Task<Stream>`	Download a file as a stream
`DeleteAsync(key)`	`Task`	Delete a file
`ExistsAsync(key)`	`Task<bool>`	Check if a file exists
`GetMetadataAsync(key)`	`Task<FileMetadata?>`	Get file metadata
`GetPresignedUrlAsync(key, expiry)`	`Task<string>`	Generate a time-limited direct URL

`FileMetadata`¶

public record FileMetadata(
    string Key,
    string Filename,
    string ContentType,
    long Size,
    string? ETag,
    DateTimeOffset CreatedAt);

Usage¶

// Upload and generate a download link
from metadata in StorageEffects.FileStore.UploadAsync<AppRuntime>(
    "invoices/2024/inv-001.pdf", pdfStream, "application/pdf")
from url in StorageEffects.FileStore.GetPresignedUrlAsync<AppRuntime>(
    metadata.Key, TimeSpan.FromMinutes(15))
select new { metadata.Key, DownloadUrl = url };

Resilience¶

Apply resilience via a wrapper interface extending IFileStore:

public interface IResilientFileStore : IFileStore
{
    [Retry(MaxAttempts = 3)]
    [Timeout(30_000)]
    new Task<FileMetadata> UploadAsync(string key, Stream content, string contentType);
}

See the Effects module resilience section for details on [Retry], [Timeout], and [CircuitBreaker].

Pluggable Implementations¶

Register a concrete IFileStore implementation in DI. The effect module delegates to whichever implementation is registered:

// Azure Blob Storage
services.AddSingleton<IFileStore, AzureBlobFileStore>();

// Amazon S3
services.AddSingleton<IFileStore, S3FileStore>();

// Local filesystem (development)
services.AddSingleton<IFileStore, LocalFileStore>();