Function Open

gorm.go:138–258

Open initialize db session based on dialector

(dialector Dialector, opts ...Option)

// Open initialize db session based on dialector
func Open(dialector Dialector, opts ...Option) (db *DB, err error) {
	config := &Config{}

	sort.Slice(opts, func(i, j int) bool {
		_, isConfig := opts[i].(*Config)
		_, isConfig2 := opts[j].(*Config)
		return isConfig && !isConfig2
	})

	if len(opts) > 0 {
		if c, ok := opts[0].(*Config); ok {
			config = c
		} else {
			opts = append([]Option{config}, opts...)
		}
	}

	var skipAfterInitialize bool
	for _, opt := range opts {
		if opt != nil {
			if applyErr := opt.Apply(config); applyErr != nil {
				return nil, applyErr
			}
			defer func(opt Option) {
				if skipAfterInitialize {
					return
				}
				if errr := opt.AfterInitialize(db); errr != nil {
					err = errr
				}
			}(opt)
		}
	}

	if d, ok := dialector.(interface{ Apply(*Config) error }); ok {
		if err = d.Apply(config); err != nil {
			return
		}
	}

	if config.NamingStrategy == nil {
		config.NamingStrategy = schema.NamingStrategy{IdentifierMaxLength: 64} // Default Identifier length is 64
	}

	if config.Logger == nil {
		config.Logger = logger.Default
	}

	if config.NowFunc == nil {
		config.NowFunc = func() time.Time { return time.Now().Local() }
	}

	if dialector != nil {
		config.Dialector = dialector
	}

	if config.Plugins == nil {
		config.Plugins = map[string]Plugin{}