MagicCSharp.Data.Postgres 1.0.2

MagicCSharp.Data.Postgres

PostgreSQL wiring for MagicCSharp.Data.EntityFramework: a pooled context factory read from configuration that fails at startup rather than on the first query, a design-time factory for dotnet ef, and an interceptor for the one timestamptz mistake that only ever shows up on a developer's machine.

Add it to the data project alongside MagicCSharp.Data.EntityFramework when the database is Postgres.

dotnet add package MagicCSharp.Data.Postgres

Registration

builder.Services.AddPostgresDbContextFactory<MagicShopContext>(builder.Configuration);

Reads DB_HOST, DB_PORT, DB_NAME, DB_USER and DB_PASSWORD. Each is required — a missing one throws rather than quietly defaulting to localhost. Set a different ConfigPrefix on PostgresConnectionOptions to point a second context at another database (VECTOR_DB_HOST, and so on).

Registers a pooled factory, which is what makes the repositories' context-per-operation cheap: pooling reuses the context and its internal service provider rather than rebuilding the model each time. Opens one connection during registration, so a wrong host or password fails at startup instead of on the first request that needs the database; set DB_VERIFY_CONNECTION=false where that is wrong — a test that swaps every repository out, or a container that starts before its database.

Pool sizes, timeouts and retry live in PostgresConnectionOptions. Size MaxPoolSize against the server's limit divided by the number of instances you run, or a rolling deploy will exhaust the server.

Two hooks for the provider, also on PostgresConnectionOptions: ConfigureDataSource for an Npgsql type plugin such as pgvector's UseVector(), and ConfigureNpgsql for the options inside UseNpgsql. A query that Includes two collections at once throws rather than multiplying the rows — that is almost never what was meant, and throwing turns a silent performance cliff into a fix-once error.

Migrations

public class MagicShopContextFactory() : MagicDbContextFactory<MagicShopContext>("shop");

dotnet ef builds the context without your DI container, so it needs this. Without one it falls back to booting the whole host just to read a connection string. The argument is the default database name; host, port, user and password default to a local Postgres and are overridden by the same DB_* variables.

The UTC interceptor

Registered for you. It normalizes every DateTimeOffset command parameter to UTC.

MagicDbContext already does that on save, but save only sees entities. A Where comparing a timestamp, an ExecuteUpdate, an ExecuteDelete and raw SQL all bind parameters without going near the change tracker. Npgsql requires offset zero for a timestamptz parameter, so one of those carrying a local offset throws at bind time — on a developer's machine, and not in CI, because CI runs in UTC.

Related packages

• MagicCSharp.Data.EntityFramework — the repository base classes this wires up
• MagicCSharp.Testing.Database — repository tests against a real PostgreSQL

The whole picture, and the optional repository layout: github.com/MagicDoorInc/MagicCSharp. MIT.