Dloizides.Jobs.AspNetCore 1.1.3

Dloizides.Jobs.AspNetCore

The ASP.NET Core real-time wire for Dloizides.Jobs. Background-job status is durable and pollable out of the box; this package adds opt-in PUSH to the browser. MapJobStatusStream mounts an SSE and/or WebSocket endpoint that subscribes to the job status backplane and streams authoritative JobStatus snapshots to connected clients.

It is a separate package on purpose: the core stays free of Microsoft.AspNetCore so a worker with no HTTP surface can still run jobs. This package adds only a FrameworkReference to Microsoft.AspNetCore.App — SSE and WebSocket are both built on framework primitives, no third-party dependency.

Persist first, push second

Push is never load-bearing. The backplane event is only a hint ("job X changed"); on each event the wire re-reads the durable JobStatus via IJobStatusQuery and pushes that. So a push client and a poll client render identical truth, and a dropped notification or a blipped socket is healed by the next poll or a reconnect-then-snapshot (every connection sends an initial snapshot on open).

Wiring

// 1. A backplane in Dloizides.Jobs core / a transport package, selected by config:
builder.AddDloizidesJobs(jobs =>
{
    jobs.AddJob<IngestJob>();
    jobs.UseEntityFrameworkStore<AppDbContext>();
    jobs.UsePostgresStatusBackplane<AppDbContext>();   // cross-pod fan-out (Dloizides.Jobs.EntityFrameworkCore)
});

// 2. Register the wires (both; config decides which mount):
builder.Services.AddJobStatusStreaming();

var app = builder.Build();
app.UseWebSockets();          // required only if the WebSocket wire is used
app.MapJobStatusStream();     // default path: /jobs/status/stream

// appsettings.json
"Jobs": {
  "Status": {
    "Backplane": "Postgres",   // None (default) | InMemory | Postgres
    "Wire": "Sse"              // Sse (default) | WebSocket | Both
  }
}

• SSE serves the base path (/jobs/status/stream). One-directional, browser EventSource auto-reconnect, proxy-friendly. Frames: event: <kind>\ndata: <JobStatus json>\n\n, plus : keep-alive heartbeats.
• WebSocket serves {path}/ws. JSON { kind, status } text frames + app-level heartbeat frames.
• Both mounts both. A ?job=<name> query narrows a connection to a single job (otherwise all jobs stream).

Each connection subscribes to the pod's backplane, re-queries the store per event in a fresh scope (no DbContext held open for the connection's life), and tolerates a client vanishing mid-stream without faulting the server.

Scale

When Postgres fan-out becomes the bottleneck, swap Jobs:Status:Backplane to a broker-backed transport (e.g. Redis) — the wire is unchanged.

License

MIT.