Add simulation nodes

internal/simulation/cdnnode.go

@@ -12,14 +12,14 @@ type CDNNode struct {
 	CachingStrategy string
 	Compression     string
 	HTTP2           string
-	CacheHitRate    float64             // % of requests served from edge cache
+	CacheHitRate    float64
-	CurrentLoad     int                 // optional: can track active queue length
+	CurrentLoad     int
-	Queue           []*Request          // incoming request queue
+	Queue           []*Request
-	EdgeNodes       map[string]*CDNNode // future expansion: simulate geographic edge clusters
+	EdgeNodes       map[string]*CDNNode
 	Alive           bool
 	Targets         []string
-	output          []*Request // cache HIT responses
+	output          []*Request
-	missQueue       []*Request // cache MISSes to forward
+	missQueue       []*Request
 }
 
 func (n *CDNNode) GetID() string          { return n.ID }
@@ -27,7 +27,7 @@ func (n *CDNNode) Type() string           { return "cdn" }
 func (n *CDNNode) IsAlive() bool          { return n.Alive }
 func (n *CDNNode) QueueState() []*Request { return n.Queue }
 
-func (n *CDNNode) Tick(tick int) {
+func (n *CDNNode) Tick(tick int, currentTimeMs int) {
 	if len(n.Queue) == 0 {
 		return
 	}
@@ -35,17 +35,15 @@ func (n *CDNNode) Tick(tick int) {
 	maxProcessPerTick := 10
 	processCount := min(len(n.Queue), maxProcessPerTick)
 
-	// Avoid slice leak by reusing a cleared slice
 	queue := n.Queue
 	n.Queue = n.Queue[:0]
 
 	for i := 0; i < processCount; i++ {
 		req := queue[i]
 
-		// Simulate cache hit or miss
 		hitRate := n.CacheHitRate
 		if hitRate == 0 {
-			hitRate = 0.8 // default if unset
+			hitRate = 0.8
 		}
 
 		if rand.Float64() < hitRate {
@@ -61,9 +59,8 @@ func (n *CDNNode) Tick(tick int) {
 		}
 	}
 
-	// Optionally simulate cache expiration every 100 ticks
+	if len(queue) > processCount {
-	if tick%100 == 0 {
+		n.Queue = append(n.Queue, queue[processCount:]...)
-		// e.g., simulate reduced hit rate or TTL expiration
 	}
 }
 
@@ -81,7 +78,6 @@ func (n *CDNNode) Receive(req *Request) {
 func (n *CDNNode) Emit() []*Request {
 	out := append(n.output, n.missQueue...)
 
-	// Clear for next tick
 	n.output = n.output[:0]
 	n.missQueue = n.missQueue[:0]
 

internal/simulation/databasenode.go

@@ -9,8 +9,8 @@ type DatabaseNode struct {
 	Replicas         []*DatabaseNode
 	Alive            bool
 	Targets          []string
-	output           []*Request
+	Output           []*Request
-	replicationQueue []*Request
+	ReplicationQueue []*Request
 }
 
 func (n *DatabaseNode) GetID() string        { return n.ID }
@@ -18,7 +18,7 @@ func (n *DatabaseNode) Type() string         { return "database" }
 func (n *DatabaseNode) IsAlive() bool        { return n.Alive }
 func (n *DatabaseNode) GetQueue() []*Request { return n.Queue }
 
-func (n *DatabaseNode) Tick(tick int) {
+func (n *DatabaseNode) Tick(tick int, currentTimeMs int) {
 	if len(n.Queue) == 0 {
 		return
 	}
@@ -35,12 +35,11 @@ func (n *DatabaseNode) Tick(tick int) {
 		if req.Type == "READ" {
 			req.LatencyMS += 20
 			req.Path = append(req.Path, n.ID)
-			n.output = append(n.output, req)
+			n.Output = append(n.Output, req)
 		} else {
 			req.LatencyMS += 50
 			req.Path = append(req.Path, n.ID)
 
-			// Replicate to replicas
 			for _, replica := range n.Replicas {
 				replicationReq := &Request{
 					ID:        req.ID + "-repl",
@@ -50,14 +49,13 @@ func (n *DatabaseNode) Tick(tick int) {
 					Type:      "REPLICATION",
 					Path:      append(append([]string{}, req.Path...), "->"+replica.ID),
 				}
-				n.replicationQueue = append(n.replicationQueue, replicationReq)
+				n.ReplicationQueue = append(n.ReplicationQueue, replicationReq)
 			}
 
-			n.output = append(n.output, req)
+			n.Output = append(n.Output, req)
 		}
 	}
 
-	// Apply queuing penalty if overloaded
 	if len(n.Queue) > 10 {
 		for _, req := range n.Queue {
 			req.LatencyMS += 10
@@ -74,8 +72,8 @@ func (n *DatabaseNode) Receive(req *Request) {
 }
 
 func (n *DatabaseNode) Emit() []*Request {
-	out := append(n.output, n.replicationQueue...)
+	out := append(n.Output, n.ReplicationQueue...)
-	n.output = n.output[:0]
+	n.Output = n.Output[:0]
-	n.replicationQueue = n.replicationQueue[:0]
+	n.ReplicationQueue = n.ReplicationQueue[:0]
 	return out
 }

internal/simulation/engine.go

@@ -14,9 +14,9 @@ type Request struct {
 }
 
 type SimulationNode interface {
-	ID() string
+	GetID() string
 	Type() string
-	Tick(tick int)
+	Tick(tick int, currentTimeMs int)
 	Receive(req *Request)
 	Emit() []*Request
 	IsAlive() bool
@@ -35,18 +35,117 @@ type TickSnapshot struct {
 	NodeHealth map[string]string
 }
 
-func NewEngineFromDesign(design simulation.Design, duration int, tickMs int) *Engine {
+func NewEngineFromDesign(design design.Design, duration int, tickMs int) *Engine {
-	nodes := design.ToSimulationNode()
+	nodeMap := make(map[string]SimulationNode)
-	nodeMap := make(make[string]SimulatSimulationNode)
+
-	for _, n := range nodes {
+	for _, n := range design.Nodes {
-		nodeMap[n.ID] = n
+		var simNode SimulationNode
+
+		switch n.Type {
+		case "webserver":
+			simNode = &WebServerNode{
+				ID:    n.ID,
+				Alive: true,
+				Queue: []*Request{},
+			}
+		case "cache":
+			simNode = &CacheNode{
+				ID:             n.ID,
+				Label:          n.Props["label"].(string),
+				CacheTTL:       int(n.Props["cacheTTL"].(float64)),
+				MaxEntries:     int(n.Props["maxEntries"].(float64)),
+				EvictionPolicy: n.Props["evictionPolicy"].(string),
+				CurrentLoad:    0,
+				Queue:          []*Request{},
+				Cache:          make(map[string]CacheEntry),
+				Alive:          true,
+			}
+		case "database":
+			simNode = &DatabaseNode{
+				ID:          n.ID,
+				Label:       n.Props["label"].(string),
+				Replication: int(n.Props["replication"].(float64)),
+				Queue:       []*Request{},
+				Alive:       true,
+			}
+		case "cdn":
+			simNode = &CDNNode{
+				ID:              n.ID,
+				Label:           n.Props["label"].(string),
+				TTL:             int(n.Props["ttl"].(float64)),
+				GeoReplication:  n.Props["geoReplication"].(string),
+				CachingStrategy: n.Props["cachingStrategy"].(string),
+				Compression:     n.Props["compression"].(string),
+				HTTP2:           n.Props["http2"].(string),
+				Queue:           []*Request{},
+				Alive:           true,
+				output:          []*Request{},
+				missQueue:       []*Request{},
+			}
+		case "messageQueue":
+			simNode = &MessageQueueNode{
+				ID:         n.ID,
+				Label:      n.Props["label"].(string),
+				QueueSize:  int(n.Props["maxSize"].(float64)),
+				MessageTTL: int(n.Props["retentionSeconds"].(float64)),
+				DeadLetter: false,
+				Queue:      []*Request{},
+				Alive:      true,
+			}
+		case "microservice":
+			simNode = &MicroserviceNode{
+				ID:             n.ID,
+				Label:          n.Props["label"].(string),
+				APIEndpoint:    n.Props["apiVersion"].(string),
+				RateLimit:      int(n.Props["rpsCapacity"].(float64)),
+				CircuitBreaker: true,
+				Queue:          []*Request{},
+				CircuitState:   "closed",
+				Alive:          true,
+			}
+		case "third party service":
+			simNode = &ThirdPartyServiceNode{
+				ID:          n.ID,
+				Label:       n.Props["label"].(string),
+				APIEndpoint: n.Props["provider"].(string),
+				RateLimit:   int(n.Props["latency"].(float64)),
+				RetryPolicy: "exponential",
+				Queue:       []*Request{},
+				Alive:       true,
+			}
+		case "data pipeline":
+			simNode = &DataPipelineNode{
+				ID:             n.ID,
+				Label:          n.Props["label"].(string),
+				BatchSize:      int(n.Props["batchSize"].(float64)),
+				Transformation: n.Props["transformation"].(string),
+				Queue:          []*Request{},
+				Alive:          true,
+			}
+		case "monitoring/alerting":
+			// Simulation not implemented yet; optionally skip
+			continue
+		default:
+			continue
+		}
+
+		if simNode != nil {
+			nodeMap[simNode.GetID()] = simNode
+		}
+	}
+
+	// Wire up connections
+	for _, conn := range design.Connections {
+		if sourceNode, ok := nodeMap[conn.Source]; ok {
+			if targetSetter, ok := sourceNode.(interface{ AddTarget(string) }); ok {
+				targetSetter.AddTarget(conn.Target)
+			}
+		}
 	}
 
 	return &Engine{
-		Nodes: nodeMap,
+		Nodes:    nodeMap,
 		Duration: duration,
-		TickMs: tickMs,
+		TickMs:   tickMs,
 	}
 }
-
-

internal/simulation/loadbalancer.go

@@ -25,7 +25,7 @@ func (lb *LoadBalancerNode) Receive(req *Request) {
 	lb.Queue = append(lb.Queue)
 }
 
-func (lb *LoadBalancerNode) Tick(tick int) {
+func (lb *LoadBalancerNode) Tick(tick int, currentTimeMs int) {
 	lb.Processed = nil
 
 	for _, req := range lb.Queue {

internal/simulation/messagequeuenode.go

@@ -0,0 +1,93 @@
+package simulation
+
+type MessageQueueNode struct {
+	ID               string
+	Label            string
+	QueueSize        int
+	MessageTTL       int // TTL in milliseconds
+	DeadLetter       bool
+	CurrentLoad      int
+	Queue            []*Request
+	Alive            bool
+	Targets          []string
+	output           []*Request
+	deadLetterOutput []*Request
+}
+
+func (n *MessageQueueNode) GetID() string { return n.ID }
+func (n *MessageQueueNode) Type() string  { return "messagequeue" }
+func (n *MessageQueueNode) IsAlive() bool { return n.Alive }
+
+func (n *MessageQueueNode) Tick(tick int, currentTimeMs int) {
+	if len(n.Queue) == 0 {
+		return
+	}
+
+	// Message queues have very high throughput
+	maxProcessPerTick := 20 // Higher than database (3) or CDN (10)
+	processCount := min(len(n.Queue), maxProcessPerTick)
+
+	// Check for queue overflow (simulate back pressure)
+	if len(n.Queue) > n.QueueSize {
+		// Move oldest messages to dead letter queue if enabled
+		if n.DeadLetter {
+			overflow := len(n.Queue) - n.QueueSize
+			for i := 0; i < overflow; i++ {
+				deadReq := n.Queue[i]
+				deadReq.Type = "DEAD_LETTER"
+				deadReq.Path = append(deadReq.Path, n.ID+"(dead)")
+				n.deadLetterOutput = append(n.deadLetterOutput, deadReq)
+			}
+			n.Queue = n.Queue[overflow:]
+		} else {
+			// Drop messages if no dead letter queue
+			n.Queue = n.Queue[:n.QueueSize]
+		}
+	}
+
+	// Process messages with TTL check
+	for i := 0; i < processCount; i++ {
+		req := n.Queue[0]
+		n.Queue = n.Queue[1:]
+
+		// Check TTL (time to live) - use current time in milliseconds
+		messageAgeMs := currentTimeMs - req.Timestamp
+		if messageAgeMs > n.MessageTTL {
+			// Message expired
+			if n.DeadLetter {
+				req.Type = "EXPIRED"
+				req.Path = append(req.Path, n.ID+"(expired)")
+				n.deadLetterOutput = append(n.deadLetterOutput, req)
+			}
+			// Otherwise drop expired message
+			continue
+		}
+
+		// Message queue adds minimal latency (very fast)
+		req.LatencyMS += 2
+		req.Path = append(req.Path, n.ID)
+		n.output = append(n.output, req)
+	}
+}
+
+func (n *MessageQueueNode) Receive(req *Request) {
+	if req == nil {
+		return
+	}
+
+	// Message queues have very low receive overhead
+	req.LatencyMS += 1
+
+	n.Queue = append(n.Queue, req)
+}
+
+func (n *MessageQueueNode) Emit() []*Request {
+	// Return both normal messages and dead letter messages
+	allRequests := append(n.output, n.deadLetterOutput...)
+
+	// Clear queues
+	n.output = n.output[:0]
+	n.deadLetterOutput = n.deadLetterOutput[:0]
+
+	return allRequests
+}

internal/simulation/microservicenode.go

@@ -0,0 +1,103 @@
+package simulation
+
+import "math/rand"
+
+type MicroserviceNode struct {
+	ID             string
+	Label          string
+	APIEndpoint    string
+	RateLimit      int // max requests per tick
+	CircuitBreaker bool
+	CircuitState   string // "closed", "open", "half-open"
+	ErrorCount     int
+	CurrentLoad    int
+	Queue          []*Request
+	Output         []*Request
+	Alive          bool
+	Targets        []string
+}
+
+func (n *MicroserviceNode) GetID() string { return n.ID }
+
+func (n *MicroserviceNode) Type() string { return "microservice" }
+
+func (n *MicroserviceNode) IsAlive() bool { return n.Alive }
+
+func (n *MicroserviceNode) Receive(req *Request) {
+	n.Queue = append(n.Queue, req)
+}
+
+func (n *MicroserviceNode) Emit() []*Request {
+	out := append([]*Request(nil), n.Output...)
+	n.Output = n.Output[:0]
+	return out
+}
+
+func (n *MicroserviceNode) Tick(tick int, currentTimeMs int) {
+	if !n.Alive {
+		return
+	}
+
+	// Simulate circuit breaker state transitions
+	switch n.CircuitState {
+	case "open":
+		// Skip processing
+		return
+	case "half-open":
+		// Allow limited testing traffic
+		if len(n.Queue) == 0 {
+			return
+		}
+		req := n.Queue[0]
+		n.Queue = n.Queue[1:]
+		req.LatencyMS += 15
+		req.Path = append(req.Path, n.ID+"(half-open)")
+		success := simulateSuccess()
+		if success {
+			n.CircuitState = "closed"
+			n.ErrorCount = 0
+			n.Output = append(n.Output, req)
+		} else {
+			n.ErrorCount++
+			n.CircuitState = "open"
+		}
+		return
+	}
+
+	// "closed" circuit - normal processing
+	toProcess := min(len(n.Queue), n.RateLimit)
+	for i := 0; i < toProcess; i++ {
+		req := n.Queue[i]
+		req.LatencyMS += 10
+		req.Path = append(req.Path, n.ID)
+
+		if simulateFailure() {
+			n.ErrorCount++
+			if n.CircuitBreaker && n.ErrorCount > 5 {
+				n.CircuitState = "open"
+				break
+			}
+			continue
+		}
+
+		n.Output = append(n.Output, req)
+	}
+	n.Queue = n.Queue[toProcess:]
+
+	// Health check: simple example
+	n.Alive = n.CircuitState != "open"
+}
+
+func simulateFailure() bool {
+	// Simulate 10% failure rate
+	return randInt(1, 100) <= 10
+}
+
+func simulateSuccess() bool {
+	// Simulate 90% success rate
+	return randInt(1, 100) <= 90
+}
+
+func randInt(min, max int) int {
+	return min + rand.Intn(max-min+1)
+}

internal/simulation/monitoringnode.go

@@ -0,0 +1,66 @@
+package simulation
+
+type MonitoringNode struct {
+	ID             string
+	Label          string
+	Tool           string
+	AlertMetric    string
+	ThresholdValue int
+	ThresholdUnit  string
+	Queue          []*Request
+	Alive          bool
+	Targets        []string
+	Metrics        map[string]int
+	Alerts         []*Request
+}
+
+func (n *MonitoringNode) GetID() string { return n.ID }
+
+func (n *MonitoringNode) Type() string { return "monitoring" }
+
+func (n *MonitoringNode) IsAlive() bool { return n.Alive }
+
+func (n *MonitoringNode) Receive(req *Request) {
+	n.Queue = append(n.Queue, req)
+}
+
+func (n *MonitoringNode) Emit() []*Request {
+	out := append([]*Request(nil), n.Alerts...)
+	n.Alerts = n.Alerts[:0]
+	return out
+}
+
+func (n *MonitoringNode) Tick(tick int, currentTimeMs int) {
+	if !n.Alive {
+		return
+	}
+
+	if n.Metrics == nil {
+		n.Metrics = make(map[string]int)
+	}
+
+	// Simulate processing requests as metrics
+	for _, req := range n.Queue {
+		// For now, pretend all requests are relevant to the AlertMetric
+		n.Metrics[n.AlertMetric] += 1
+		req.LatencyMS += 1
+		req.Path = append(req.Path, n.ID)
+
+		if n.Metrics[n.AlertMetric] > n.ThresholdValue {
+			alert := &Request{
+				ID:        "alert-" + req.ID,
+				Timestamp: currentTimeMs,
+				Origin:    n.ID,
+				Type:      "alert",
+				LatencyMS: 0,
+				Path:      []string{n.ID, "alert"},
+			}
+			n.Alerts = append(n.Alerts, alert)
+
+			// Reset after alert (or you could continue accumulating)
+			n.Metrics[n.AlertMetric] = 0
+		}
+	}
+
+	n.Queue = nil
+}

internal/simulation/thirdpartyservicenode.go

@@ -0,0 +1,77 @@
+package simulation
+
+type ThirdPartyServiceNode struct {
+	ID          string
+	Label       string
+	APIEndpoint string
+	RateLimit   int    // Max requests per tick
+	RetryPolicy string // "exponential", "fixed", etc.
+	CurrentLoad int
+	Queue       []*Request
+	ErrorCount  int
+	RetryCount  int
+	Alive       bool
+	Targets     []string
+	Output      []*Request
+}
+
+// --- Interface Methods ---
+
+func (n *ThirdPartyServiceNode) GetID() string { return n.ID }
+func (n *ThirdPartyServiceNode) Type() string  { return "thirdpartyservice" }
+func (n *ThirdPartyServiceNode) IsAlive() bool { return n.Alive }
+func (n *ThirdPartyServiceNode) Receive(req *Request) {
+	n.Queue = append(n.Queue, req)
+}
+func (n *ThirdPartyServiceNode) Emit() []*Request {
+	out := append([]*Request(nil), n.Output...)
+	n.Output = n.Output[:0]
+	return out
+}
+
+// Add missing Queue method for interface compliance
+func (n *ThirdPartyServiceNode) GetQueue() []*Request {
+	return n.Queue
+}
+
+// --- Simulation Logic ---
+
+func (n *ThirdPartyServiceNode) Tick(tick int, currentTimeMs int) {
+	if !n.Alive {
+		return
+	}
+
+	// Simulate third-party call behavior with success/failure
+	maxProcess := min(n.RateLimit, len(n.Queue))
+	newQueue := n.Queue[maxProcess:]
+	n.Queue = nil
+
+	for i := 0; i < maxProcess; i++ {
+		req := newQueue[i]
+		success := simulateThirdPartySuccess(req)
+
+		if success {
+			req.LatencyMS += 100 + randInt(0, 50) // simulate response time
+			req.Path = append(req.Path, n.ID)
+			n.Output = append(n.Output, req)
+		} else {
+			n.ErrorCount++
+			n.RetryCount++
+			if n.RetryPolicy == "exponential" && n.RetryCount < 3 {
+				n.Queue = append(n.Queue, req) // retry again next tick
+			}
+		}
+	}
+
+	// Simulate degradation if too many errors
+	if n.ErrorCount > 10 {
+		n.Alive = false
+	}
+}
+
+// --- Helpers ---
+
+func simulateThirdPartySuccess(req *Request) bool {
+	// 90% success rate
+	return randInt(0, 100) < 90
+}

internal/simulation/webservernode.go

@@ -8,6 +8,7 @@ type WebServerNode struct {
 	PenaltyPerRPS float64
 	Processed     []*Request
 	Alive         bool
+	Targets       []string
 }
 
 func (ws *WebServerNode) GetID() string {
@@ -22,20 +23,20 @@ func (ws *WebServerNode) IsAlive() bool {
 	return ws.Alive
 }
 
-func (ws *WebServerNode) Tick(tick int) {
+func (ws *WebServerNode) Tick(tick int, currentTimeMs int) {
 	toProcess := min(ws.CapacityRPS, len(ws.Queue))
 	for i := 0; i < toProcess; i++ {
-		req := ws.Queue[0]
+		req := ws.Queue[i]
 		req.LatencyMS += ws.BaseLatencyMs
 		ws.Processed = append(ws.Processed, req)
-
-		ws.Queue[i] = nil
 	}
 
+	// Remove processed requests from the queue
 	ws.Queue = ws.Queue[toProcess:]
 
-	if len(ws.Queue) > ws.CapacityRPS {
+	// Apply penalty for overload
-		overload := len(ws.Queue) - ws.CapacityRPS
+	if len(ws.Queue) > 0 {
+		overload := len(ws.Queue)
 		for _, req := range ws.Queue {
 			req.LatencyMS += int(ws.PenaltyPerRPS * float64(overload))
 		}
@@ -52,9 +53,17 @@ func (ws *WebServerNode) Emit() []*Request {
 	return out
 }
 
+func (ws *WebServerNode) AddTarget(targetID string) {
+	ws.Targets = append(ws.Targets, targetID)
+}
+
 func min(a, b int) int {
 	if a < b {
 		return a
 	}
 	return b
 }
+
+func (ws *WebServerNode) GetQueue() []*Request {
+	return ws.Queue
+}