Feat: Backend scaffolding and local dev stack

Backend/internal/database/postgres.go

@@ -0,0 +1,95 @@
+// Path: Backend/internal/database/postgres.go
+
+package database
+
+import (
+	"context"
+	"database/sql"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+	"github.com/jackc/pgx/v5/stdlib"
+	"github.com/pressly/goose/v3"
+
+	"moku-backend/db"
+)
+
+type DB struct {
+	Pool *pgxpool.Pool
+}
+
+func NewPostgres(databaseURL string) (*DB, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	config, err := pgxpool.ParseConfig(databaseURL)
+	if err != nil {
+		return nil, err
+	}
+
+	config.MaxConns = 25
+	config.MinConns = 5
+	config.MaxConnLifetime = time.Hour
+	config.MaxConnIdleTime = 30 * time.Minute
+
+	pool, err := pgxpool.NewWithConfig(ctx, config)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := pool.Ping(ctx); err != nil {
+		pool.Close()
+		return nil, err
+	}
+
+	return &DB{Pool: pool}, nil
+}
+
+func (d *DB) MigrateUp() error {
+	return d.runGoose(goose.Up)
+}
+
+func (d *DB) MigrateDown() error {
+	return d.runGoose(goose.Down)
+}
+
+func (d *DB) MigrateReset() error {
+	return d.runGoose(goose.Reset)
+}
+
+func (d *DB) MigrateStatus() error {
+	return d.runGoose(goose.Status)
+}
+
+func (d *DB) runGoose(command func(*sql.DB, string, ...goose.OptionsFunc) error) error {
+	if d == nil || d.Pool == nil {
+		return nil
+	}
+
+	sqlDB := stdlib.OpenDBFromPool(d.Pool)
+	defer sqlDB.Close()
+
+	goose.SetBaseFS(db.Migrations)
+
+	if err := goose.SetDialect("postgres"); err != nil {
+		return err
+	}
+
+	return command(sqlDB, "migrations")
+}
+
+func (d *DB) Health(ctx context.Context) error {
+	if d == nil || d.Pool == nil {
+		return nil
+	}
+
+	return d.Pool.Ping(ctx)
+}
+
+func (d *DB) Close() {
+	if d == nil || d.Pool == nil {
+		return
+	}
+
+	d.Pool.Close()
+}