feat: 完成一般消息通知能力的开发

factory.go

@@ -0,0 +1,48 @@
+package notice
+
+import (
+	"fmt"
+	"sync"
+)
+
+type Factory struct {
+	mu        sync.RWMutex       `json:"-" dc:"实例缓存读写锁"`
+	configs   map[Channel]Config `json:"-" dc:"按渠道保存的初始化配置"`
+	instances map[Channel]Sender `json:"-" dc:"按渠道缓存的 Sender 实例"`
+}
+
+func NewFactory(configs map[Channel]Config) *Factory {
+	cloned := make(map[Channel]Config, len(configs))
+	for channel, config := range configs {
+		cloned[channel] = config
+	}
+	return &Factory{configs: cloned, instances: make(map[Channel]Sender)}
+}
+
+func (f *Factory) Get(channel Channel) (Sender, error) {
+	if f == nil {
+		return nil, fmt.Errorf("%w: factory is nil", ErrChannelNotConfigured)
+	}
+	f.mu.RLock()
+	instance, ok := f.instances[channel]
+	f.mu.RUnlock()
+	if ok {
+		return instance, nil
+	}
+
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if instance, ok = f.instances[channel]; ok {
+		return instance, nil
+	}
+	config, ok := f.configs[channel]
+	if !ok {
+		return nil, fmt.Errorf("%w: %s", ErrChannelNotConfigured, channel)
+	}
+	instance, err := New(channel, config)
+	if err != nil {
+		return nil, err
+	}
+	f.instances[channel] = instance
+	return instance, nil
+}