Stratara.EventSourcing.EntityFrameworkCore 4.4.4

Stratara.EventSourcing.EntityFrameworkCore

Derived. The behaviour described here is specified under openspec/specs/. Those specifications are the source; this page explains and illustrates them.

License: MIT.

EF Core persistence for the Stratara event-sourced stack — PostgreSQL flavoured via Npgsql. pgvector types are mapped for a model that has vector columns; a model without them runs on a plain PostgreSQL server, no vector extension needed. Bundles four previously-separate Stratara projects into one NuGet because they always ship together:

Everything lives under Stratara.EventSourcing.EntityFrameworkCore and its sub-namespaces (.WriteStore, .ReadStore, .IdentityStore, .Abstractions, .Conventions, .Extensions, .HealthChecks, .Migration). The DI extensions sit in Microsoft.Extensions.DependencyInjection, per the Microsoft convention, so they resolve without an extra using.

Why folded

WriteStore-without-ReadStore is not a real use case. EF conventions + value generators + UnitOfWork primitives are foundational for every other store. ASP.NET Identity glue follows the same EF Core conventions. Splitting into 4 NuGets that always ship together adds version-management noise (4× <PackageVersion> to keep in sync, transitive-resolution risk) without any consumer benefit.

If your application doesn't use ASP.NET Identity, simply don't reference IdentityDbContext-derived types — the rest of the package works without them.

Quick start

Derive your contexts from the generic base classes — the type argument is the context itself:

using Stratara.EventSourcing.EntityFrameworkCore.WriteStore;
using Stratara.EventSourcing.EntityFrameworkCore.ReadStore;

public sealed class MyAppWriteDbContext(DbContextOptions<MyAppWriteDbContext> options)
    : WriteDbContext<MyAppWriteDbContext>(options);

public sealed class MyAppReadDbContext(DbContextOptions<MyAppReadDbContext> options)
    : ReadDbContext<MyAppReadDbContext>(options);

Then register the Npgsql context factories and the write store. Each factory registration also registers the unit of work over its context — IWriteUnitOfWork for the write side, IProjectionsUnitOfWork / IReadUnitOfWork for the read side — unless the host registered its own. The write-side unit of work also draws on ISessionContextProvider and ISecureJsonSerializer, which AddSessionContext() and AddSecurity() provide (every worker composite applies both); with those in place, this is all the store needs from the host:

// In your AppHost / Worker / Web project:
builder.Services
    .AddNpgsqlWriteDbContextFactory<MyAppWriteDbContext>()
    .AddNpgsqlReadDbContextFactory<MyAppReadDbContext>()
    .AddWriteStore(builder.Configuration);                    // binds Stratara:EventSourcing options

Most hosts don't call these directly — the worker composites in Stratara.EventSourcing.WorkerDefaults (AddCommandWorkerServices(), AddEventProjectionWorkerServices(), …) already compose AddWriteStore for you. Reach for the explicit form when you build a host that none of the composites fit.

Renamed in 3.2.0, removed in 4.0.0: the write-side factory was AddNpsqlWriteDbContextFactory (missing the g) through 3.1.x. AddNpgsqlWriteDbContextFactory replaced it in 3.2.0 and the old spelling stayed as an [Obsolete] alias until 4.0.0, which removed it. A host still on the old spelling adds the g; nothing else about the call changes.

Health checks

Two opt-in readiness checks plug into any IHealthChecksBuilder (they require the write store above to be registered):

builder.Services.AddHealthChecks()
    .AddEventStoreHealthCheck()                                  // write-side DB reachable?
    .AddOutboxHealthCheck(degradedThreshold: 1_000,             // outbox backlog depth
                          unhealthyThreshold: 10_000);

• AddEventStoreHealthCheck() — probes write-store connectivity; Unhealthy when the database cannot be reached.
• AddOutboxHealthCheck(degradedThreshold?, unhealthyThreshold?) — reports the pending outbox backlog under the pending data key and escalates to Degraded / Unhealthy when the count crosses the supplied thresholds (omit them to stay healthy while reachable).

Both are tagged ready by default, so they show up on a readiness endpoint rather than the liveness (live) one.

Dependencies

• Stratara.Projections — for projection types used by ProjectionsUnitOfWork.
• Stratara.Shared — for diagnostics + abstractions + resilience.
• Npgsql.EntityFrameworkCore.PostgreSQL, EFCore.NamingConventions, Microsoft.AspNetCore.Identity.EntityFrameworkCore, Microsoft.EntityFrameworkCore, Microsoft.Extensions.Diagnostics.HealthChecks, Pgvector.EntityFrameworkCore.