added a plugin register pattern adopted from the database sql interface (f0c2913b) · Commits · bsmrgo / playground

register/register.go

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		package register

		import (
		"errors"
		"sync"
		)

		// Connection contains connection related information.
		type Connection interface {
		Open(string) error
		Close() error
		}

		// Driver is an interface for drivers.
		type Driver interface {
		Open(string) (Connection, error)
		}

		const (
		helixDriverName = "helix"
		radixDriverName = "radix"
		)

		// Helix is an example driver.
		type Helix struct{}

		// Open implements the Driver interface.
		func (h *Helix) Open(dsn string) (Connection, error) {
		return nil, errors.New("not implemented yet")
		}

		// Radix is another example driver.
		type Radix struct{}

		// Open implements the Driver interface.
		func (r *Radix) Open(dsn string) (Connection, error) {
		return nil, errors.New("not implemented yet")
		}

		// Manager handles drivers.
		type Manager struct {
		driversMutex sync.RWMutex
		drivers map[string]Driver
		}

		// NewManager creates a new manager.
		func NewManager() *Manager {
		return &Manager{
		drivers: make(map[string]Driver),
		}
		}

		// Register a driver.
		func (m *Manager) Register(name string, driver Driver) {
		m.driversMutex.Lock()
		defer m.driversMutex.Unlock()

		if driver == nil {
		panic("manager: driver is nil")
		}
		if _, dup := m.drivers[name]; dup {
		panic("manager: driver is already registred: " + name)
		}
		m.drivers[name] = driver
		}

		// Drivers lists registred drivers.
		func (m *Manager) Drivers() []string {
		drivers := []string{}

		for name := range m.drivers {
		drivers = append(drivers, name)
		}

		return drivers
		}

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		package register

		import "testing"

		func TestRegister(t *testing.T) {

		m := NewManager()

		if l := len(m.Drivers()); l != 0 {
		t.Fatalf("number of drivers is %d, expected 0", l)
		}

		m.Register(helixDriverName, &Helix{})
		ds := m.Drivers()

		if l := len(ds); l != 1 {
		t.Fatalf("number of drivers is %d, expected 1", l)
		}

		m.Register(radixDriverName, &Radix{})
		ds = m.Drivers()

		if l := len(ds); l != 2 {
		t.Fatalf("number of drivers is %d, expected 1", 2)
		}

		for _, n := range ds {
		t.Logf("registred driver: %q", n)
		}
		}