vulthil-sharedkernel-infrastructure.md

Vulthil.SharedKernel.Infrastructure

Use Vulthil.SharedKernel.Infrastructure for persistence and outbox integration. It hosts the outbox engine (factored into Vulthil.SharedKernel.Outbox) and adds the DbContext base and the DI wiring (EnableOutboxProcessing).

When to use

• EF Core DbContext setup and migrations/ensure-created helpers
• Transaction wrappers and repository implementations
• Outbox persistence and background processing

Pattern

• Keep persistence mapping in infrastructure only
• Publish domain events through outbox for reliability
• Register infrastructure via composition-root extension methods

Usage

Defining a DbContext

public sealed class AppDbContext(DbContextOptions<AppDbContext> options) : BaseDbContext(options)
{
    protected override Assembly? ConfigurationAssembly => typeof(AppDbContext).Assembly;

    public DbSet<User> Users => Set<User>();

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);
        modelBuilder.ApplyNpgsqlOutbox();
    }
}

Registration with outbox processing

AddDbContext is an extension on IHostApplicationBuilder. The provider extension (e.g. UseNpgsql, in Vulthil.SharedKernel.Infrastructure.Npgsql) handles the EF Core registration, so chain it directly on the configurator:

builder.AddDbContext<AppDbContext>(config => config
    .UseNpgsql("Default")
    .EnableOutboxProcessing(o =>
    {
        o.BatchSize = 10;
        o.MaxRetries = 3;
    }));

Only one outbox-enabled DbContext is supported per host: the relay and retention background services resolve a single IOutboxStore, so a second EnableOutboxProcessing() call (on a different DbContext) throws an InvalidOperationException at startup instead of silently leaving the first context's messages unrelayed.

Generic repository

public sealed class UserRepository(AppDbContext db)
    : GenericRepository<AppDbContext, User, UserId>(db)
{
    public Task<User?> GetByEmailAsync(string email, CancellationToken ct) =>
        DbContext.Users.FirstOrDefaultAsync(u => u.Email == email, ct);
}

Database initialization

// Apply pending migrations on startup
await app.MigrateAsync<AppDbContext>();

// Or ensure created (for development/testing)
await app.EnsureCreatedAsync<AppDbContext>();