File System Watcher Trigger

Process files as they appear (e.g., ingest PDFs, images, or logs; run extraction via SK).

Reliable watcher pattern

var fsw = new FileSystemWatcher("/data/inbox")
{
    IncludeSubdirectories = false,
    NotifyFilter = NotifyFilters.FileName | NotifyFilters.Size | NotifyFilters.LastWrite,
    Filter = "*.*",
    EnableRaisingEvents = true
};

var queue = Channel<string>.CreateUnbounded();
fsw.Created += (_, e) => queue.Writer.TryWrite(e.FullPath);
fsw.Changed += (_, e) => queue.Writer.TryWrite(e.FullPath);

_ = Task.Run(async () =>
{
    var pending = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
    await foreach (var path in queue.Reader.ReadAllAsync())
    {
        pending.Add(path);
        await Task.Delay(500); // debounce
        foreach (var p in pending.ToArray())
        {
            if (IsStable(p)) { await ProcessAsync(p); pending.Remove(p); }
        }
    }
});

• On startup, do a full directory scan to catch missed files.
• In containers, mount volumes and ensure inotify limits are sufficient.

Pros / Cons

• Pros: Near-real-time ETL; simple local integration.
• Cons: Event storms and partial writes; must debounce and verify stability.