Lyo.ChangeTracker.Postgres 2.0.1

Lyo.ChangeTracker.Postgres

PostgreSQL adapter for Lyo.ChangeTracker. Stores entity-scoped change history using Lyo.EntityReference.Models.EntityRef for both the target entity and the optional actor.

Features

• PostgresChangeTracker implementing Lyo.Health.IHealth and IChangeTracker
• EF Core migrations in the change_tracker schema (PostgresChangeTrackerOptions.Schema)
• Queryable history by entity type, entity, or change id (newest first)
• DeleteForEntityAsync drops all history for a target entity
• Optional automatic migrations on startup via EnableAutoMigrations

Examples

First steps

services.AddPostgresChangeTracker(new PostgresChangeTrackerOptions {
    ConnectionString = configuration.GetConnectionString("ChangeTracker")!,
    EnableAutoMigrations = true
});

services.AddPostgresChangeTrackerFromConfiguration(configuration);

Migrations

export CHANGE_TRACKER_CONNECTION_STRING="Host=localhost;Database=change_tracker;Username=postgres;Password=postgres"
dotnet ef migrations add MigrationName --project Core/ChangeTracker/Lyo.ChangeTracker.Postgres

Registration

Registration helpers, from factory-only through IChangeTracker:

Health

HealthCheckName = "change-tracker-postgres" comes from PostgresChangeTracker implementing Lyo.Health.IHealth. The probe constructs a ChangeTrackerDbContext and calls Database.CanConnectAsync. Schema name is placed in the HealthResult data bag. Hosts resolving IEnumerable<IHealth> pick this tracker up.

Database schema

• The change_tracker schema holds every table (see PostgresChangeTrackerOptions.Schema).
• change_tracker.changes. Subject (for_entity_* / SubjectEntityType), optional actor (from_entity_* / ActorEntityType), nullable tenant_id (uuid), JSON OldValues, JSON ChangedProperties, optional ChangeType / Message, and Timestamp.

Tenancy

ChangeRecord carries an optional TenantId; null denotes a system / untenanted row. Before persist, PostgresChangeTracker runs every record through TenancyResolver.Resolve using the policy configured in PostgresChangeTrackerOptions.Tenancy (inheriting from EntityRefOptions.Mode when unset):

• SystemOnly. Caller TenantId is ignored. The row stores null.
• SingleTenantDefault (default). Caller value, falling back to Tenancy.DefaultTenantId then EntityRefOptions.DefaultTenantId.
• MultiTenantStrict. Caller must supply a non-empty TenantId or persistence throws.

The ix_changes_tenant index supports per-tenant lookups. Use the WhereTenant / WhereTenantOrSystem helpers from Lyo.EntityReference.Postgres to query the table.

{
  "PostgresChangeTracker": {
    "ConnectionString": "Host=localhost;Database=change_tracker;...",
    "Tenancy": { "Mode": "SystemOnly" }
  }
}

Dependencies

Generated from ProjectReference / PackageReference (same model as docs/Lyo.ProjectGraph.html).

• Lyo.ChangeTracker (direct, lyo)
• Lyo.Common.Core (direct, lyo)
• Lyo.EntityReference.Models (direct, lyo)
• Lyo.EntityReference.Postgres (direct, lyo)
• Lyo.Exceptions (direct, lyo)
• Lyo.Health (direct, lyo)
• Lyo.Postgres (direct, lyo)
• Microsoft.Bcl.AsyncInterfaces 10.0.5 (transitive, microsoft, netstandard2.0)
• Microsoft.EntityFrameworkCore 10.0.5 (transitive, microsoft)
• Microsoft.EntityFrameworkCore.Design 10.0.5 (transitive, microsoft)
• Microsoft.EntityFrameworkCore.Relational 10.0.5 (transitive, microsoft)
• Microsoft.Extensions.DependencyInjection.Abstractions 10.0.5 (transitive, microsoft)
• Microsoft.Extensions.Hosting.Abstractions 10.0.5 (transitive, microsoft)
• Microsoft.Extensions.Options 10.0.5 (transitive, microsoft)
• Microsoft.Extensions.Options.ConfigurationExtensions 10.0.5 (transitive, microsoft)
• Npgsql.EntityFrameworkCore.PostgreSQL 10.0.3 (transitive, third-party)
• System.Memory 4.6.3 (transitive, microsoft, netstandard2.0)
• System.Text.Json 10.0.5 (transitive, microsoft, netstandard2.0)