Add cachenode for simulation

internal/simulation/cachenode.go

@@ -0,0 +1,62 @@
+package simulation
+
+type CacheNode struct {
+	ID             string
+	Label          string
+	CacheTTL       int
+	MaxEntries     int
+	EvictionPolicy string
+	CurrentLoad    int
+	Queue          []Request
+	Cache          map[string]interface{}
+	Alive          bool
+	Targets        []string
+}
+
+func (c *CacheNode) GetID() string {
+	return c.ID
+}
+
+func (c *CacheNode) Type() string {
+	return "cache"
+}
+
+func (c *CacheNode) GetQueue() []Request {
+	return c.Queue
+}
+func (c *CacheNode) Tick(tick int) {
+	if len(c.Cache) > c.MaxEntries {
+		evictCount := len(c.Cache) - c.MaxEntries
+
+		i := 0
+
+		for k := range c.Cache {
+			delete(c.Cache, k)
+			i++
+			if i >= evictCount {
+				break
+			}
+		}
+	}
+}
+
+func (c *CacheNode) Receive(req *Request) {
+	c.Queue = append(c.Queue, *req)
+}
+
+func (c *CacheNode) Emit() []*Request {
+	var out []*Request
+
+	// emit everything in a single tick.
+	for _, req := range c.Queue {
+		// check cache
+		if _, ok := c.Cache[req.ID]; !ok {
+			c.Cache[req.ID] = struct{}{}
+			out = append(out, &req)
+		}
+	}
+	c.Queue = nil
+	return out
+}
+
+func (c *CacheNode) IsAlive() bool { return c.Alive }