ProcessPlacement

Remarks

No cluster, no daemon, no container runtime: a port from a pool, a RealmSpec on the command line, and the process's own stdio as the lifecycle channel (RealmSignals). That is enough to run a fleet on a laptop, in CI, and in a small deployment that has one machine — which doc 27 § Cost's L0 is exactly the shape of.

And it is what makes the rest of this testable. Doc 27 § Testing: this backend is to doc 27 what Vixen.Net.Transport.Local is to doc 16. Everything above the interface — placement scoring, spawn and merge hysteresis, drain, rolling upgrades — is an ordinary unit test against a fleet that starts in milliseconds, with IRealmProcessHost swapped for one that starts nothing at all.

⚠ An instance outlives this object only if you let it. Dispose kills everything it started, because a launcher that exited leaving eight realms holding UDP ports is the thing that makes a developer reboot. A deployment that wants realms to survive their launcher wants the Kubernetes backend, where an owner reference says so explicitly.

Fields and properties (1)

• public const string BackendName

  What this backend calls itself in a PlacementProbe.

Methods (7)

• public ProcessPlacement(ProcessPlacementOptions options, IRealmProcessHost? host = null, TimeProvider? time = null)

  Stands a launcher up.

• public ValueTask<PlacementProbe> ProbeAsync(CancellationToken cancellation)
• public ValueTask<RealmInstance> StartAsync(RealmSpec spec, CancellationToken cancellation)

  Brings a realm up.

• public ValueTask StopAsync(RealmInstanceId instance, StopMode mode, CancellationToken cancellation)

  Takes a realm down.

• public ValueTask<IReadOnlyList<RealmInstance>> ListAsync(CancellationToken cancellation)

  What this backend believes is running.

• public IAsyncEnumerable<PlacementEvent> WatchAsync(CancellationToken cancellation)
• public void Dispose()

  Kills everything this launcher started.

Used by (1)

• ProcessPlacementTestsVixen.Live.Placement.Process.Tests