Rene Nochebuena
4b58f8e3d9
Introduces code.nochebuena.dev/einherjar/db-postgres — the PostgreSQL database starter for the Einherjar framework. Absorbs the postgres package from micro-lib, replacing fmt.Errorf wrapping with core/xerrors and migrating from pgx v4 to pgx v5. Interfaces (CT-6: one TypeSpec per file): - Executor — Exec, Query, QueryRow (pgx-native types) - Tx — Executor + Commit(ctx), Rollback(ctx) - Provider — GetExecutor, Begin, BeginTx, Ping, HandleError - Component — lifecycle.Component + observability.Checkable + Provider + Stats() - UnitOfWork — Do(ctx, fn) Implementation: - New(logger, cfg) Component — pool not created until OnInit - OnInit: pgxpool.NewWithConfig with duration parsing; 30s timeout - OnStart: PING with 5s timeout; logs "postgres: connected" - OnStop: pool.Close(); logs "postgres: closing pool" - GetExecutor: returns active Tx from context (ctxTxKey) or pool; nil-safe - Begin/BeginTx: wraps pgx.TxOptions; wrapped in xerrors on error - HealthCheck: delegates to Ping; Priority LevelCritical - Stats() *pgxpool.Stat — zero value when pool uninitialized - NewUnitOfWork(logger, provider) UnitOfWork — Begin+inject+commit/rollback - HandleError: UniqueViolation→ErrAlreadyExists, ForeignKey/Check→ErrInvalidInput, pgx.ErrNoRows→ErrNotFound, all others→ErrInternal Config (EINHERJAR_PG_* env vars): Host, Port(5432), User, Password, Name, SSLMode(disable), Timezone(UTC), MaxConns(5), MinConns(2), MaxConnLifetime(1h), MaxConnIdleTime(30m), HealthCheckPeriod(1m) - Component interface embeds observability.Identifiable; identifiable.go implements ModulePath and ModuleVersion via runtime/debug.ReadBuildInfo() — prints in launcher banner
58 lines
2.0 KiB
Go
58 lines
2.0 KiB
Go
// Package postgres provides a pgx-backed PostgreSQL client with lifecycle management,
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// health checks, and unit-of-work transaction support for Einherjar applications.
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//
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// # Overview
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//
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// [New] returns a [Component] that manages a [pgxpool.Pool] connection pool,
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// satisfies the [lifecycle.Component] lifecycle hooks (OnInit, OnStart, OnStop),
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// and implements [observability.Checkable] with critical priority.
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//
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// [NewUnitOfWork] wraps multiple repository operations in a single transaction
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// via context injection — no transaction object is passed between functions.
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//
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// # Lifecycle Registration
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//
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// db := postgres.New(logger, cfg)
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// launcher.Register(db)
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// health.Register(db)
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//
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// # Querying
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//
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// Repository code receives a [Provider] or [Executor] and calls [Provider.GetExecutor]
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// to obtain the active transaction (if inside a [UnitOfWork]) or the pool:
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//
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// exec := db.GetExecutor(ctx)
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// row := exec.QueryRow(ctx, "SELECT id FROM users WHERE email = $1", email)
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// if err := row.Scan(&id); err != nil {
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// return db.HandleError(err) // maps pgx.ErrNoRows → ErrNotFound, etc.
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// }
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//
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// # Unit of Work
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//
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// [NewUnitOfWork] wraps operations in a single transaction. The transaction is
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// injected into the context; [Provider.GetExecutor] returns it automatically.
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//
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// uow := postgres.NewUnitOfWork(logger, db)
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// err := uow.Do(ctx, func(ctx context.Context) error {
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// exec := db.GetExecutor(ctx) // returns active Tx
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// _, err := exec.Exec(ctx, "INSERT INTO orders ...")
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// return err
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// })
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//
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// # Error Handling
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//
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// [HandleError] translates pgx and PostgreSQL error codes into typed
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// [xerrors] values. Call it at every point where a pgx error is first observed:
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//
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// if err := row.Scan(&out); err != nil {
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// return db.HandleError(err)
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// }
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//
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// Mapped codes:
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// - UniqueViolation → ErrAlreadyExists
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// - ForeignKeyViolation → ErrInvalidInput
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// - CheckViolation → ErrInvalidInput
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// - pgx.ErrNoRows → ErrNotFound
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// - all others → ErrInternal
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package postgres
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