AddJunctionProgress

Adds junction-level progress tracking and cross-server cancellation checking as junction effects. Before each junction, checks the database for a cancellation signal and writes the currently running junction name to metadata. After each junction, clears the progress columns.

Signature

public static TBuilder AddJunctionProgress<TBuilder>(
    this TBuilder effectBuilder
)
    where TBuilder : TraxEffectBuilder

The generic type parameter TBuilder is inferred by the compiler, so callers just write .AddJunctionProgress(). This preserves the concrete builder type through chaining (e.g., TraxEffectBuilderWithData stays as TraxEffectBuilderWithData).

Parameters

None.

Returns

TBuilder, the same builder type that was passed in, for continued fluent chaining.

Example

services.AddTrax(trax => trax
    .AddEffects(effects => effects
        .UsePostgres(connectionString)
        .AddJunctionProgress()
    )
);

Remarks

• This is a junction-level effect (runs per junction, not per train).
• Registers two providers: CancellationCheckProvider (runs first) and JunctionProgressProvider.
• CancellationCheckProvider queries the database before each junction to check Metadata.CancellationRequested. If true, it throws OperationCanceledException, which FinishTrain maps to TrainState.Cancelled.
• JunctionProgressProvider sets Metadata.CurrentlyRunningJunction and Metadata.JunctionStartedAt before each junction, and clears them after.
• Both providers are registered as toggleable junction effects visible on the dashboard Effects page.
• Requires a data provider (UsePostgres or UseInMemory) to be registered. Build-time validation: If no data provider is configured, the application throws InvalidOperationException at startup with a message explaining the required configuration.

Package

dotnet add package Trax.Effect.JunctionProvider.Progress