discovery

type Batch struct {
	KVs []KeyValue
}

type Closed struct{}

type Discovery interface {
	// 从service center中获得数据
	Get(ctx context.Context, key string) ([]byte, error)                                         // 根据key获得value
	List(ctx context.Context, prefix string) ([]KeyValue, error)                                 // 根据前缀获得数据
	Put(ctx context.Context, key string, val []byte) error                                       // key-value写入， 为了控制面使用
	Delete(ctx context.Context, key string) error                                                // 删除key，为了控制面使用
	Heartbeat(ctx context.Context, key string, value []byte, ttl int64) (<-chan Closed, error)   // endponit 健康检查
	Elect(ctx context.Context, key string, value []byte, ttl int64) (bool, <-chan Closed, error) // 选举写入： key 不存在，写入成功，返回成功；key存在，写入失败，返回error
	Watch(ctx context.Context, key string, fetchVal bool) WatchEventChan                         // watch key
	WatchPrefix(ctx context.Context, prefixKey string, fetchVal bool) WatchEventChan             // watch 前缀key
	Batch(ctx context.Context, batch Batch) (bool, error)                                        // 批写入
	NewTransaction() Transaction                                                                 // 新transaction
	Commit(ctx context.Context, txn Transaction) error                                           // commit
	Close() error                                                                                // close discovery
}

type DiscoveryFactory interface {
	CreateDiscovery(cfg config.Discovery) (Discovery, error)
}

type Event struct {
	Type      EventType
	KeyValues []EventKeyValue

	Err error
}

type EventKeyValue struct {
	Key   string
	Value []byte
	Rev   int64
}

type EventType int

type KeyValue struct {
	Key   string
	Value []byte
}

type Transaction interface {
	ModRevisionCmp(key, op string, v interface{})
	Put(key string, value []byte)
	Delete(key string)
}

type WatchEventChan <-chan *Event