feat: 完善后端脚手架基础能力

database/database.go

@@ -0,0 +1,169 @@
+package database
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"skeleton/config"
+
+	"go.uber.org/zap"
+	"gorm.io/driver/mysql"
+	"gorm.io/driver/postgres"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+)
+
+var DB *gorm.DB
+
+// Init 根据配置的 driver 初始化数据库连接。
+func Init(cfg *config.DatabaseConfig, log *zap.Logger) error {
+	if err := prepareSQLiteDirectory(cfg); err != nil {
+		return err
+	}
+
+	dialector, err := Dialector(cfg)
+	if err != nil {
+		return err
+	}
+
+	gormLogger := logger.New(
+		&GormZapWriter{Logger: log},
+		logger.Config{
+			SlowThreshold: time.Second,
+			LogLevel:      logger.Info,
+			Colorful:      false,
+		},
+	)
+
+	db, err := gorm.Open(dialector, &gorm.Config{Logger: gormLogger})
+	if err != nil {
+		return fmt.Errorf("连接 %s 数据库失败: %w", cfg.Driver, err)
+	}
+
+	sqlDB, err := db.DB()
+	if err != nil {
+		return fmt.Errorf("获取底层数据库连接失败: %w", err)
+	}
+
+	sqlDB.SetMaxIdleConns(cfg.MaxIdleConns)
+	sqlDB.SetMaxOpenConns(cfg.MaxOpenConns)
+	sqlDB.SetConnMaxLifetime(time.Duration(cfg.ConnMaxLifetime) * time.Minute)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	if err := sqlDB.PingContext(ctx); err != nil {
+		_ = sqlDB.Close()
+		return fmt.Errorf("%s 数据库连接测试失败: %w", cfg.Driver, err)
+	}
+
+	DB = db
+	log.Info("数据库连接初始化成功",
+		zap.String("driver", cfg.Driver),
+		zap.String("database", databaseName(cfg)),
+		zap.Int("max_idle_conns", cfg.MaxIdleConns),
+		zap.Int("max_open_conns", cfg.MaxOpenConns),
+	)
+	return nil
+}
+
+func prepareSQLiteDirectory(cfg *config.DatabaseConfig) error {
+	driver := strings.ToLower(strings.TrimSpace(cfg.Driver))
+	if driver != "sqlite" && driver != "sqlite3" {
+		return nil
+	}
+
+	path := BuildDSN(cfg)
+	if path == "" || path == ":memory:" || strings.HasPrefix(path, "file:") {
+		return nil
+	}
+
+	dir := filepath.Dir(path)
+	if dir == "." {
+		return nil
+	}
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return fmt.Errorf("创建 SQLite 数据目录失败: %w", err)
+	}
+	return nil
+}
+
+// Dialector 创建对应数据库的 GORM 方言实例，便于应用和测试复用。
+func Dialector(cfg *config.DatabaseConfig) (gorm.Dialector, error) {
+	driver := strings.ToLower(strings.TrimSpace(cfg.Driver))
+	dsn := BuildDSN(cfg)
+
+	switch driver {
+	case "postgres", "postgresql":
+		return postgres.Open(dsn), nil
+	case "mysql":
+		return mysql.Open(dsn), nil
+	case "sqlite", "sqlite3":
+		return sqliteDialector(dsn)
+	default:
+		return nil, fmt.Errorf("不支持的数据库驱动 %q，可选值: postgres, mysql, sqlite", cfg.Driver)
+	}
+}
+
+// BuildDSN 返回显式 DSN，或根据结构化配置构建对应方言的连接串。
+func BuildDSN(cfg *config.DatabaseConfig) string {
+	if cfg.DSN != "" {
+		return cfg.DSN
+	}
+
+	switch strings.ToLower(strings.TrimSpace(cfg.Driver)) {
+	case "mysql":
+		return fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=utf8mb4&parseTime=True&loc=Local",
+			cfg.Username, cfg.Password, cfg.Host, cfg.Port, cfg.DBName)
+	case "sqlite", "sqlite3":
+		return cfg.SQLitePath
+	default:
+		return fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=%s sslmode=%s",
+			cfg.Host, cfg.Port, cfg.Username, cfg.Password, cfg.DBName, cfg.SSLMode)
+	}
+}
+
+func databaseName(cfg *config.DatabaseConfig) string {
+	if strings.HasPrefix(strings.ToLower(cfg.Driver), "sqlite") {
+		return BuildDSN(cfg)
+	}
+	return cfg.DBName
+}
+
+func Close() error {
+	if DB == nil {
+		return nil
+	}
+	sqlDB, err := DB.DB()
+	if err != nil {
+		return err
+	}
+	return sqlDB.Close()
+}
+
+func GetDB() *gorm.DB {
+	return DB
+}
+
+// Ping 检查关系数据库连接是否可用。
+func Ping(ctx context.Context) error {
+	if DB == nil {
+		return fmt.Errorf("数据库尚未初始化")
+	}
+	sqlDB, err := DB.DB()
+	if err != nil {
+		return err
+	}
+	return sqlDB.PingContext(ctx)
+}
+
+type GormZapWriter struct {
+	Logger *zap.Logger
+}
+
+func (g *GormZapWriter) Printf(format string, args ...interface{}) {
+	g.Logger.Info(fmt.Sprintf(format, args...))
+}