节点环绕通知（Around Advice）：在节点OnMsg方法执行之前和之后执行。该类型增强点，可以替换原节点逻辑。可以实现节点故障转移、重试、缓存等功能。

Before、After、Around Advice 执行顺序：Around->Before->Around

接口

// Order 返回执行顺序，值越小，优先级越高
Order() int
// 规则链初始化时候会调用该方法创建新的实例，如果字段值需要继承，在这里处理
New() Aspect
// PointCut 声明一个切入点，用于判断是否需要执行增强点
//例如：指定某些组件类型或者relationType才执行切面逻辑;return ctx.Self().Type()=="mqttClient"
PointCut(ctx RuleContext, msg RuleMsg, relationType string) bool
//Around 节点 OnMsg 方法执行环绕的增强点。
//如果返回false:引擎不会调用当前节点的OnMsg方法，需要Aspect手动触发，如：ctx.Self().OnMsg(ctx, msg)，或者通过 ctx.TellNext(msg, relationType) 控制流程。
//如果返回true：引擎会调用当前节点的OnMsg方法。
Around(ctx RuleContext, msg RuleMsg, relationType string) (RuleMsg, bool)

Around msg返回值无法影响下一个节点入参，请用 before 切面或者通过 ctx.TellNext(msg, relationType) 控制。

示例

type AroundAspect struct {
	Name string
}

func (aspect *AroundAspect) Order() int {
	return 5
}

func (aspect *AroundAspect) New() types.Aspect {
	return &AroundAspect{}
}

func (aspect *AroundAspect) PointCut(ctx types.RuleContext, msg types.RuleMsg, relationType string) bool {
	return true
}

func (aspect *AroundAspect) Around(ctx types.RuleContext, msg types.RuleMsg, relationType string) (types.RuleMsg, bool) {
	fmt.Printf("debug Around before ruleChainId:%s,flowType:%s,nodeId:%s,msg:%+v,relationType:%s \n", ctx.RuleChain().GetNodeId().Id, "Around", ctx.Self().GetNodeId().Id, msg, relationType)
	msg.Metadata.PutValue(ctx.GetSelfId()+"_before", ctx.GetSelfId()+"_before")
	// 执行当前节点逻辑
	ctx.Self().OnMsg(ctx, msg)
	//获取执行结果
	//ctx.GetOut()
    fmt.Printf("debug Around after ruleChainId:%s,flowType:%s,nodeId:%s,msg:%+v,relationType:%s \n", ctx.RuleChain().GetNodeId().Id, "Around", ctx.Self().GetNodeId().Id, msg, relationType)
	//返回false,脱离框架不重复执行该节点逻辑
	return msg, false
}

func TestAroundAspect(t *testing.T) {
var chain = `
{
  "ruleChain": {
    "id": "rule8848",
    "name": "测试规则链",
    "root": true
  },
  "metadata": {
    "nodes": [
      {
        "id": "s1",
        "type": "jsFilter",
        "name": "过滤",
        "debugMode": true,
        "configuration": {
          "jsScript": "return msg.role=='admin';"
        }
      },
      {
        "id": "s2",
        "type": "jsTransform",
        "name": "转换",
        "debugMode": true,
        "configuration": {
          "jsScript": "msg.userName=msg.userName+'NO-1';\n return {'msg':msg,'metadata':metadata,'msgType':msgType};"
        }
      }
    ],
    "connections": [
         {
        "fromId": "s1",
        "toId": "s2",
        "type": "False"
      }
    ]
  }
}
`
chainId := "test_around_aspect"

config := NewConfig()

ruleEngine, err := DefaultPool.New(chainId, []byte(chain), WithConfig(config), types.WithAspects(
&AroundAspect{Name: "AroundAspect1"},
))
if err != nil {
t.Error(err)
}
metaData := types.NewMetadata()
metaData.PutValue("productType", "test01")
msg := types.NewMsg(0, "TEST_MSG_TYPE1", types.JSON, metaData, "{\"temperature\":41}")

ruleEngine.OnMsg(msg)
time.Sleep(time.Millisecond * 200)
}