Trax

JSON Effect

The JSON effect tracks model changes by comparing JSON snapshots. When a train calls SaveChanges, this provider serializes every tracked model to JSON and compares it to the snapshot taken when the model was first tracked. If something changed, it logs the current state.

This is a development debugging tool. It doesn't persist anything — it writes to your configured ILogger.

Registration

dotnet add package Trax.Effect.Provider.Json
services.AddTrax(trax => trax
    .AddEffects(effects => effects
        .AddJson()
    )
);

No configuration required. The provider uses the JSON serialization options from ITraxEffectConfiguration and logs at the level configured there.

How It Works

  1. When the EffectRunner calls Track(model), the JSON effect serializes the model to a JSON string and stores that snapshot alongside a reference to the model.
  2. When SaveChanges runs at the end of the train, the provider re-serializes every tracked model and compares the new JSON to the stored snapshot.
  3. If the JSON differs — a field was updated, a state changed — the provider logs the new serialized state.

This gives you a log of what changed during train execution without needing a database. When you see a train misbehaving, the JSON effect shows you the model states at the point they were saved.

When to Use It

  • Development — See train state changes in your console output without setting up Postgres.
  • Debugging — When a train produces unexpected results, the JSON logs show exactly what each model looked like at SaveChanges time.
  • Lightweight setups — Pair it with UseInMemory() for a no-infrastructure development environment.

In production, you'll typically replace this with (or supplement it by) the Data Persistence provider.

SDK Reference

> AddJson