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 — 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