tercul-backend/internal/platform/db/db.go

package db

import (
	"fmt"
	"time"

	"gorm.io/driver/postgres"
	"gorm.io/gorm"
	gormlogger "gorm.io/gorm/logger"
	"tercul/internal/platform/config"
	"tercul/internal/platform/log"
)

// DB is a global database connection instance
var DB *gorm.DB

// Connect establishes a connection to the database using configuration settings
// It returns the database connection and any error encountered
func Connect() (*gorm.DB, error) {
	log.LogInfo("Connecting to database",
		log.F("host", config.Cfg.DBHost),
		log.F("database", config.Cfg.DBName))

	dsn := config.Cfg.GetDSN()
	db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{
		Logger: gormlogger.Default.LogMode(gormlogger.Warn),
	})
	if err != nil {
		return nil, fmt.Errorf("failed to connect to database: %w", err)
	}

	// Set the global DB instance
	DB = db

	// Get the underlying SQL DB instance
	sqlDB, err := db.DB()
	if err != nil {
		return nil, fmt.Errorf("failed to get SQL DB instance: %w", err)
	}

	// Set connection pool settings
	sqlDB.SetMaxOpenConns(20) // Connection pooling
	sqlDB.SetMaxIdleConns(5)  // Idle connections
	sqlDB.SetConnMaxLifetime(30 * time.Minute)

	log.LogInfo("Successfully connected to database",
		log.F("host", config.Cfg.DBHost),
		log.F("database", config.Cfg.DBName))

	return db, nil
}

// Close closes the database connection
func Close() error {
	if DB == nil {
		return nil
	}

	sqlDB, err := DB.DB()
	if err != nil {
		return fmt.Errorf("failed to get SQL DB instance: %w", err)
	}

	return sqlDB.Close()
}

// InitDB initializes the database connection and runs migrations
// It returns the database connection and any error encountered
func InitDB() (*gorm.DB, error) {
	// Connect to the database
	db, err := Connect()
	if err != nil {
		return nil, err
	}

	// Run migrations
	if err := RunMigrations(db); err != nil {
		return nil, fmt.Errorf("failed to run migrations: %w", err)
	}

	return db, nil
}