规则引擎

pkg/rule_engine/nodes/action_delay_node.go

@@ -0,0 +1,76 @@
+package nodes
+
+import (
+	"fmt"
+	"pandax/pkg/rule_engine/message"
+	"sync"
+	"time"
+
+	"github.com/sirupsen/logrus"
+)
+
+const DelayNodeName = "DelayNode"
+
+type delayNode struct {
+	bareNode
+	PeriodTs           int               `json:"periodTs" yaml:"periodTs" jpath:"periodTs"`
+	MaxPendingMessages int               `json:"maxPendingMessages" yaml:"maxPendingMessages" jpath:"maxPendingMessages"`
+	messageQueue       []message.Message `jpath:"-"`
+	delayTimer         *time.Timer       `jpath:"-"`
+	lock               sync.Mutex        `jpath:"-"`
+}
+
+type delayNodeFactory struct{}
+
+func (f delayNodeFactory) Name() string     { return DelayNodeName }
+func (f delayNodeFactory) Category() string { return NODE_CATEGORY_ACTION }
+
+func (f delayNodeFactory) Create(id string, meta Metadata) (Node, error) {
+	labels := []string{"Success", "Failure"}
+	node := &delayNode{
+		bareNode: newBareNode(f.Name(), id, meta, labels),
+		lock:     sync.Mutex{},
+	}
+	_, err := decodePath(meta, node)
+	node.messageQueue = make([]message.Message, node.MaxPendingMessages)
+	return node, err
+}
+
+func (n *delayNode) Handle(msg message.Message) error {
+	logrus.Infof("%s handle message '%s'", n.Name(), msg.GetType())
+
+	successLabelNode := n.GetLinkedNode("Success")
+	failureLabelNode := n.GetLinkedNode("Failure")
+	if successLabelNode == nil || failureLabelNode == nil {
+		return fmt.Errorf("no valid label linked node in %s", n.Name())
+	}
+
+	// check wethere the time had already been started, queue message if started
+	if n.delayTimer == nil {
+		n.messageQueue = append(n.messageQueue, msg)
+		n.delayTimer = time.NewTimer(time.Duration(n.PeriodTs) * time.Second)
+		// start timecallback goroutine
+		go func(n *delayNode) error {
+			defer n.delayTimer.Stop()
+			for {
+				<-n.delayTimer.C
+				n.lock.Lock()
+				defer n.lock.Unlock()
+				if len(n.messageQueue) > 0 {
+					msg := n.messageQueue[0]
+					n.messageQueue = n.messageQueue[0:]
+					return successLabelNode.Handle(msg)
+				}
+			}
+		}(n)
+		return nil
+	}
+	// the delay timer had already been created, just queue message
+	n.lock.Lock()
+	defer n.lock.Unlock()
+	if len(n.messageQueue) == n.MaxPendingMessages {
+		return failureLabelNode.Handle(msg)
+	}
+	n.messageQueue = append(n.messageQueue, msg)
+	return nil
+}