AddTraxStateMachineSelfCheck

Registers the state-machine runtime self-check as an ASP.NET Core health check. On every check it replays each registered machine's committed differential corpus through the engine this build shipped, and reports Unhealthy with every diff when a machine no longer reproduces it. That is drift a build-time test cannot see, because it runs against the deployed binary.

Signature

namespace Trax.Effect.StateMachine.Persistence;
 
public static class StateMachineHealthCheckExtensions
{
    public static IHealthChecksBuilder AddTraxStateMachineSelfCheck(
        this IHealthChecksBuilder builder,
        string name = "state-machines"
    );
}

Parameter	Type	Default	Description
`builder`	`IHealthChecksBuilder`		The builder `AddHealthChecks()` returns
`name`	`string`	`"state-machines"`	The health check's registration name

Returns: the IHealthChecksBuilder, for chaining. There is no tags parameter; to tag the check, register it under your own name and filter by name.

Behavior

Situation	Result
Every machine reproduces its corpus	`Healthy`, "Every state machine reproduces its committed corpus."
Any machine drifts	`Unhealthy`, with one line per diff, prefixed by the machine
A machine ships no corpus (`IMachine.Corpus` is null)	Skipped, not failed

It resolves every IMachine that AddStateMachines registered, so it needs no configuration and picks up a new machine automatically.
The replay runs synchronously on each call and ignores the cancellation token. Its cost grows with corpus size, so poll it at a modest interval.
It calls SnapshotSelfCheck.Run(machines), the same check a host can run itself, for example from an IHostedService at startup.

Example

builder.Services.AddTrax(trax => trax
    .AddEffects(effects => effects.UsePostgres(connectionString))
    .AddStateMachines(typeof(Program).Assembly)
    .AddMediator(typeof(Program).Assembly));
 
builder.Services.AddHealthChecks().AddTraxStateMachineSelfCheck();
 
var app = builder.Build();
app.MapHealthChecks("/health");

Package

dotnet add package Trax.Effect.StateMachine.Persistence