Merge pull request 'feature/improved-cluster-forming' (#15) from feature/improved-cluster-forming into main

Reviewed-on: #15

ctl.sh

@@ -372,12 +372,9 @@ function node {
             
             # Cluster Configuration
             echo "=== Cluster Configuration ==="
-            echo "Discovery Interval: $(echo "$response_body" | jq -r '.cluster.discovery_interval_ms // "N/A"') ms"
             echo "Heartbeat Interval: $(echo "$response_body" | jq -r '.cluster.heartbeat_interval_ms // "N/A"') ms"
             echo "Cluster Listen Interval: $(echo "$response_body" | jq -r '.cluster.cluster_listen_interval_ms // "N/A"') ms"
             echo "Status Update Interval: $(echo "$response_body" | jq -r '.cluster.status_update_interval_ms // "N/A"') ms"
-            echo "Member Info Update Interval: $(echo "$response_body" | jq -r '.cluster.member_info_update_interval_ms // "N/A"') ms"
-            echo "Print Interval: $(echo "$response_body" | jq -r '.cluster.print_interval_ms // "N/A"') ms"
             echo ""
             
             # Node Status Thresholds

docs/Architecture.md

@@ -42,65 +42,79 @@ The cluster uses a UDP-based discovery protocol for automatic node detection:
 
 ### Discovery Process
 
-1. **Discovery Broadcast**: Nodes periodically send UDP packets on port `udp_port` (default 4210)
-2. **Response Handling**: Nodes respond with `CLUSTER_RESPONSE:<hostname>`
-3. **Member Management**: Discovered nodes are added/updated in the cluster
-4. **Node Info via UDP**: Heartbeat triggers peers to send `CLUSTER_NODE_INFO:<hostname>:<json>`
+1. **Discovery Broadcast**: Nodes periodically send heartbeat messages on port `udp_port` (default 4210)
+2. **Response Handling**: Nodes respond with node update information containing their current state
+3. **Member Management**: Discovered nodes are added/updated in the cluster with current information
+4. **Node Synchronization**: Periodic broadcasts ensure all nodes maintain current cluster state
 
 ### Protocol Details
 
 - **UDP Port**: 4210 (configurable via `Config.udp_port`)
-- **Discovery Message**: `CLUSTER_DISCOVERY`
-- **Response Message**: `CLUSTER_RESPONSE`
-- **Heartbeat Message**: `CLUSTER_HEARTBEAT`
-- **Node Info Message**: `CLUSTER_NODE_INFO:<hostname>:<json>`
+- **Heartbeat Message**: `CLUSTER_HEARTBEAT:hostname`
+- **Node Update Message**: `NODE_UPDATE:hostname:{json}`
 - **Broadcast Address**: 255.255.255.255
-- **Discovery Interval**: `Config.discovery_interval_ms` (default 1000 ms)
 - **Listen Interval**: `Config.cluster_listen_interval_ms` (default 10 ms)
 - **Heartbeat Interval**: `Config.heartbeat_interval_ms` (default 5000 ms)
 
 ### Message Formats
 
-- **Discovery**: `CLUSTER_DISCOVERY`
-  - Sender: any node, broadcast to 255.255.255.255:`udp_port`
-  - Purpose: announce presence and solicit peer identification
-- **Response**: `CLUSTER_RESPONSE:<hostname>`
-  - Sender: node receiving a discovery; unicast to requester IP
-  - Purpose: provide hostname so requester can register/update member
-- **Heartbeat**: `CLUSTER_HEARTBEAT:<hostname>`
+- **Heartbeat**: `CLUSTER_HEARTBEAT:hostname`
   - Sender: each node, broadcast to 255.255.255.255:`udp_port` on interval
-  - Purpose: prompt peers to reply with their node info and keep liveness
-- **Node Info**: `CLUSTER_NODE_INFO:<hostname>:<json>`
-  - Sender: node receiving a heartbeat; unicast to heartbeat sender IP
-  - JSON fields: freeHeap, chipId, sdkVersion, cpuFreqMHz, flashChipSize, optional labels
+  - Purpose: announce presence, prompt peers for node info, and keep liveness
+- **Node Update**: `NODE_UPDATE:hostname:{json}`
+  - Sender: node responding to heartbeat or broadcasting current state
+  - JSON fields: hostname, ip, uptime, optional labels
+  - Purpose: provide current node information for cluster synchronization
 
 ### Discovery Flow
 
-1. **Sender broadcasts** `CLUSTER_DISCOVERY`
-2. **Each receiver responds** with `CLUSTER_RESPONSE:<hostname>` to the sender IP
-3. **Sender registers/updates** the node using hostname and source IP
-
-### Heartbeat Flow
-
-1. **A node broadcasts** `CLUSTER_HEARTBEAT:<hostname>`
-2. **Each receiver replies** with `CLUSTER_NODE_INFO:<hostname>:<json>` to the heartbeat sender IP
+1. **A node broadcasts** `CLUSTER_HEARTBEAT:hostname` to announce its presence
+2. **Each receiver responds** with `NODE_UPDATE:hostname:{json}` containing current node state
 3. **The sender**:
-   - Ensures the node exists or creates it with `hostname` and sender IP
-   - Parses JSON and updates resources, labels, `status = ACTIVE`, `lastSeen = now`
-   - Sets `latency = now - lastHeartbeatSentAt` (per-node, measured at heartbeat origin)
+   - Ensures the responding node exists or creates it with current IP and information
+   - Parses JSON and updates node info, `status = ACTIVE`, `lastSeen = now`
+   - Calculates `latency = now - lastHeartbeatSentAt` for network performance monitoring
+
+### Node Synchronization
+
+1. **Event-driven broadcasts**: Nodes broadcast `NODE_UPDATE:hostname:{json}` when node information changes
+2. **All receivers**: Update their memberlist entry for the broadcasting node
+3. **Purpose**: Ensures all nodes maintain current cluster state and configuration
+
+### Sequence Diagram
+
+```mermaid
+sequenceDiagram
+    participant N1 as Node A (esp-node1)
+    participant N2 as Node B (esp-node2)
+
+    Note over N1,N2: Discovery via heartbeat broadcast
+    N1->>+N2: CLUSTER_HEARTBEAT:esp-node1
+
+    Note over N2: Node B responds with its current state
+    N2->>+N1: NODE_UPDATE:esp-node1:{"hostname":"esp-node2","uptime":12345,"labels":{"role":"sensor"}}
+
+    Note over N1: Process NODE_UPDATE response
+    N1-->>N1: Update memberlist for Node B
+    N1-->>N1: Set Node B status = ACTIVE
+    N1-->>N1: Calculate latency for Node B
+
+    Note over N1,N2: Event-driven node synchronization
+    N1->>+N2: NODE_UPDATE:esp-node1:{"hostname":"esp-node1","uptime":12346,"labels":{"role":"controller"}}
+
+    Note over N2: Update memberlist with latest information
+    N2-->>N2: Update Node A info, maintain ACTIVE status
+```
 
 ### Listener Behavior
 
 The `cluster_listen` task parses one UDP packet per run and dispatches by prefix to:
-- **Discovery** → send `CLUSTER_RESPONSE`
-- **Heartbeat** → send `CLUSTER_NODE_INFO` JSON
-- **Response** → add/update node using provided hostname and source IP
-- **Node Info** → update resources/status/labels and record latency
+- **Heartbeat** → add/update responding node and send `NODE_UPDATE` response
+- **Node Update** → update node information and trigger memberlist logging
 
 ### Timing and Intervals
 
 - **UDP Port**: `Config.udp_port` (default 4210)
-- **Discovery Interval**: `Config.discovery_interval_ms` (default 1000 ms)
 - **Listen Interval**: `Config.cluster_listen_interval_ms` (default 10 ms)
 - **Heartbeat Interval**: `Config.heartbeat_interval_ms` (default 5000 ms)
 
@@ -120,12 +134,9 @@ The system runs several background tasks at different intervals:
 
 | Task | Interval (default) | Purpose |
 |------|--------------------|---------|
-| `cluster_discovery` | 1000 ms | Send UDP discovery packets |
-| `cluster_listen` | 10 ms | Listen for discovery/heartbeat/node-info |
+| `cluster_listen` | 10 ms | Listen for heartbeat/node-info messages |
 | `status_update` | 1000 ms | Update node status categories, purge dead |
 | `heartbeat` | 5000 ms | Broadcast heartbeat and update local resources |
-| `cluster_update_members_info` | 10000 ms | Reserved; no-op (info via UDP) |
-| `print_members` | 5000 ms | Log current member list |
 
 ### Task Management Features
 
@@ -142,12 +153,12 @@ The `NodeContext` provides an event-driven architecture for system-wide communic
 
 ```cpp
 // Subscribe to events
-ctx.on("node_discovered", [](void* data) {
+ctx.on("node/discovered", [](void* data) {
     NodeInfo* node = static_cast<NodeInfo*>(data);
     // Handle new node discovery
 });
 
-ctx.on("cluster_updated", [](void* data) {
+ctx.on("cluster/updated", [](void* data) {
     // Handle cluster membership changes
 });
 ```
@@ -156,13 +167,13 @@ ctx.on("cluster_updated", [](void* data) {
 
 ```cpp
 // Publish events
-ctx.fire("node_discovered", &newNode);
-ctx.fire("cluster_updated", &clusterData);
+ctx.fire("node/discovered", &newNode);
+ctx.fire("cluster/updated", &clusterData);
 ```
 
 ### Available Events
 
-- **`node_discovered`**: New node added or local node refreshed
+- **`node/discovered`**: New node added or local node refreshed
 
 ## Resource Monitoring
 

docs/ConfigurationManagement.md

@@ -93,12 +93,9 @@ The configuration is stored as a JSON file with the following structure:
     "api_server_port": 80
   },
   "cluster": {
-    "discovery_interval_ms": 1000,
     "heartbeat_interval_ms": 5000,
     "cluster_listen_interval_ms": 10,
-    "status_update_interval_ms": 1000,
-    "member_info_update_interval_ms": 10000,
-    "print_interval_ms": 5000
+    "status_update_interval_ms": 1000
   },
   "thresholds": {
     "node_active_threshold_ms": 10000,

include/spore/core/ClusterManager.h

@@ -14,7 +14,6 @@ class ClusterManager {
 public:
     ClusterManager(NodeContext& ctx, TaskManager& taskMgr);
     void registerTasks();
-    void sendDiscovery();
     void listen();
     void addOrUpdateNode(const String& nodeHost, IPAddress nodeIP);
     void updateAllNodeStatuses();
@@ -25,6 +24,7 @@ public:
     void updateLocalNodeResources();
     void heartbeatTaskCallback();
     void updateAllMembersInfoTaskCallback();
+    void broadcastNodeUpdate();
 private:
     NodeContext& ctx;
     TaskManager& taskManager;
@@ -35,18 +35,15 @@ private:
 	};
 	void initMessageHandlers();
 	void handleIncomingMessage(const char* incoming);
-	static bool isDiscoveryMsg(const char* msg);
 	static bool isHeartbeatMsg(const char* msg);
-	static bool isResponseMsg(const char* msg);
-	static bool isNodeInfoMsg(const char* msg);
+	static bool isNodeUpdateMsg(const char* msg);
 	static bool isClusterEventMsg(const char* msg);
 	static bool isRawMsg(const char* msg);
-	void onDiscovery(const char* msg);
 	void onHeartbeat(const char* msg);
-	void onResponse(const char* msg);
-	void onNodeInfo(const char* msg);
+	void onNodeUpdate(const char* msg);
 	void onClusterEvent(const char* msg);
 	void onRawMessage(const char* msg);
+	void sendNodeInfo(const String& hostname, const IPAddress& targetIP);
 	unsigned long lastHeartbeatSentAt = 0;
 	std::vector<MessageHandler> messageHandlers;
 };

include/spore/internal/Globals.h

@@ -5,10 +5,9 @@
 
 // Cluster protocol and API constants
 namespace ClusterProtocol {
-    constexpr const char* DISCOVERY_MSG = "CLUSTER_DISCOVERY";
-    constexpr const char* RESPONSE_MSG = "CLUSTER_RESPONSE";
+    // Simplified heartbeat-only protocol
     constexpr const char* HEARTBEAT_MSG = "CLUSTER_HEARTBEAT";
-    constexpr const char* NODE_INFO_MSG = "CLUSTER_NODE_INFO";
+    constexpr const char* NODE_UPDATE_MSG = "NODE_UPDATE";
     constexpr const char* CLUSTER_EVENT_MSG = "CLUSTER_EVENT";
     constexpr const char* RAW_MSG = "RAW";
     constexpr uint16_t UDP_PORT = 4210;
@@ -18,12 +17,9 @@ namespace ClusterProtocol {
 }
 
 namespace TaskIntervals {
-    constexpr unsigned long SEND_DISCOVERY = 1000;
-    constexpr unsigned long LISTEN_FOR_DISCOVERY = 100;
     constexpr unsigned long UPDATE_STATUS = 1000;
     constexpr unsigned long PRINT_MEMBER_LIST = 5000;
     constexpr unsigned long HEARTBEAT = 2000;
-    constexpr unsigned long UPDATE_ALL_MEMBERS_INFO = 10000;
 }
 
 constexpr unsigned long NODE_ACTIVE_THRESHOLD = 10000;

include/spore/types/Config.h

@@ -12,11 +12,10 @@ public:
     static constexpr const char* DEFAULT_WIFI_PASSWORD = "th3r31sn0sp00n";
     static constexpr uint16_t DEFAULT_UDP_PORT = 4210;
     static constexpr uint16_t DEFAULT_API_SERVER_PORT = 80;
-    static constexpr unsigned long DEFAULT_DISCOVERY_INTERVAL_MS = 1000;
     static constexpr unsigned long DEFAULT_CLUSTER_LISTEN_INTERVAL_MS = 10;
     static constexpr unsigned long DEFAULT_HEARTBEAT_INTERVAL_MS = 5000;
     static constexpr unsigned long DEFAULT_STATUS_UPDATE_INTERVAL_MS = 1000;
-    static constexpr unsigned long DEFAULT_MEMBER_INFO_UPDATE_INTERVAL_MS = 10000;
+    static constexpr unsigned long DEFAULT_NODE_UPDATE_BROADCAST_INTERVAL_MS = 5000;
     static constexpr unsigned long DEFAULT_PRINT_INTERVAL_MS = 5000;
     static constexpr unsigned long DEFAULT_NODE_ACTIVE_THRESHOLD_MS = 10000;
     static constexpr unsigned long DEFAULT_NODE_INACTIVE_THRESHOLD_MS = 60000;
@@ -38,12 +37,9 @@ public:
     uint16_t api_server_port;
     
     // Cluster Configuration
-    unsigned long discovery_interval_ms;
     unsigned long heartbeat_interval_ms;
     unsigned long cluster_listen_interval_ms;
     unsigned long status_update_interval_ms;
-    unsigned long member_info_update_interval_ms;
-    unsigned long print_interval_ms;
     
     // Node Status Thresholds
     unsigned long node_active_threshold_ms;

include/spore/types/NodeInfo.h

@@ -9,6 +9,7 @@ struct NodeInfo {
     String hostname;
     IPAddress ip;
     unsigned long lastSeen;
+    unsigned long uptime = 0; // milliseconds since node started
     enum Status { ACTIVE, INACTIVE, DEAD } status;
     struct Resources {
         uint32_t freeHeap = 0;
@@ -17,7 +18,7 @@ struct NodeInfo {
         uint32_t cpuFreqMHz = 0;
         uint32_t flashChipSize = 0;
     } resources;
-    unsigned long latency = 0; // ms from heartbeat broadcast to NODE_INFO receipt
+    unsigned long latency = 0; // ms from heartbeat broadcast to NODE_UPDATE receipt
     std::vector<EndpointInfo> endpoints; // List of registered endpoints
     std::map<String, String> labels; // Arbitrary node labels (key -> value)
 };

src/spore/core/ClusterManager.cpp

@@ -3,8 +3,8 @@
 #include "spore/util/Logging.h"
 
 ClusterManager::ClusterManager(NodeContext& ctx, TaskManager& taskMgr) : ctx(ctx), taskManager(taskMgr) {
-    // Register callback for node_discovered event
-    ctx.on("node_discovered", [this](void* data) {
+    // Register callback for node/discovered event
+    ctx.on("node/discovered", [this](void* data) {
         NodeInfo* node = static_cast<NodeInfo*>(data);
         this->addOrUpdateNode(node->hostname, node->ip);
     });
@@ -25,27 +25,30 @@ ClusterManager::ClusterManager(NodeContext& ctx, TaskManager& taskMgr) : ctx(ctx
         this->ctx.udp->write(msg.c_str());
         this->ctx.udp->endPacket();
     });
+
+    // Handler for node update broadcasts: services fire 'cluster/node/update' when their node info changes
+    ctx.on("cluster/node/update", [this](void* data) {
+        // Trigger immediate NODE_UPDATE broadcast when node info changes
+        broadcastNodeUpdate();
+    });
+
+    // Handler for memberlist changes: print memberlist when it changes
+    ctx.on("cluster/memberlist/changed", [this](void* data) {
+        printMemberList();
+    });
     // Register tasks
     registerTasks();
     initMessageHandlers();
 }
 
 void ClusterManager::registerTasks() {
-    taskManager.registerTask("cluster_discovery", ctx.config.discovery_interval_ms, [this]() { sendDiscovery(); });
     taskManager.registerTask("cluster_listen", ctx.config.cluster_listen_interval_ms, [this]() { listen(); });
     taskManager.registerTask("status_update", ctx.config.status_update_interval_ms, [this]() {  updateAllNodeStatuses(); removeDeadNodes(); });
-    taskManager.registerTask("print_members", ctx.config.print_interval_ms, [this]() { printMemberList(); });
     taskManager.registerTask("heartbeat", ctx.config.heartbeat_interval_ms, [this]() { heartbeatTaskCallback(); });
-    taskManager.registerTask("cluster_update_members_info", ctx.config.member_info_update_interval_ms, [this]() { updateAllMembersInfoTaskCallback(); });
     LOG_INFO("ClusterManager", "Registered all cluster tasks");
 }
 
-void ClusterManager::sendDiscovery() {
-    //LOG_DEBUG(ctx, "Cluster", "Sending discovery packet...");
-    ctx.udp->beginPacket("255.255.255.255", ctx.config.udp_port);
-    ctx.udp->write(ClusterProtocol::DISCOVERY_MSG);
-    ctx.udp->endPacket();
-}
+// Discovery functionality removed - using heartbeat-only approach
 
 void ClusterManager::listen() {
     int packetSize = ctx.udp->parsePacket();
@@ -69,10 +72,8 @@ void ClusterManager::listen() {
 void ClusterManager::initMessageHandlers() {
     messageHandlers.clear();
     messageHandlers.push_back({ &ClusterManager::isRawMsg,  [this](const char* msg){ this->onRawMessage(msg);  }, "RAW" });
-    messageHandlers.push_back({ &ClusterManager::isDiscoveryMsg, [this](const char* msg){ this->onDiscovery(msg); }, "DISCOVERY" });
     messageHandlers.push_back({ &ClusterManager::isHeartbeatMsg, [this](const char* msg){ this->onHeartbeat(msg); }, "HEARTBEAT" });
-    messageHandlers.push_back({ &ClusterManager::isResponseMsg,  [this](const char* msg){ this->onResponse(msg);  }, "RESPONSE"  });
-    messageHandlers.push_back({ &ClusterManager::isNodeInfoMsg,  [this](const char* msg){ this->onNodeInfo(msg);  }, "NODE_INFO" });
+    messageHandlers.push_back({ &ClusterManager::isNodeUpdateMsg, [this](const char* msg){ this->onNodeUpdate(msg); }, "NODE_UPDATE" });
     messageHandlers.push_back({ &ClusterManager::isClusterEventMsg,  [this](const char* msg){ this->onClusterEvent(msg);  }, "CLUSTER_EVENT" });
 }
 
@@ -94,20 +95,12 @@ void ClusterManager::handleIncomingMessage(const char* incoming) {
     LOG_DEBUG("Cluster", String("Unknown cluster message: ") + head);
 }
 
-bool ClusterManager::isDiscoveryMsg(const char* msg) {
-    return strcmp(msg, ClusterProtocol::DISCOVERY_MSG) == 0;
-}
-
 bool ClusterManager::isHeartbeatMsg(const char* msg) {
     return strncmp(msg, ClusterProtocol::HEARTBEAT_MSG, strlen(ClusterProtocol::HEARTBEAT_MSG)) == 0;
 }
 
-bool ClusterManager::isResponseMsg(const char* msg) {
-    return strncmp(msg, ClusterProtocol::RESPONSE_MSG, strlen(ClusterProtocol::RESPONSE_MSG)) == 0;
-}
-
-bool ClusterManager::isNodeInfoMsg(const char* msg) {
-    return strncmp(msg, ClusterProtocol::NODE_INFO_MSG, strlen(ClusterProtocol::NODE_INFO_MSG)) == 0;
+bool ClusterManager::isNodeUpdateMsg(const char* msg) {
+    return strncmp(msg, ClusterProtocol::NODE_UPDATE_MSG, strlen(ClusterProtocol::NODE_UPDATE_MSG)) == 0;
 }
 
 bool ClusterManager::isClusterEventMsg(const char* msg) {
@@ -123,87 +116,171 @@ bool ClusterManager::isRawMsg(const char* msg) {
     return msg[prefixLen] == ':';
 }
 
-void ClusterManager::onDiscovery(const char* /*msg*/) {
-    ctx.udp->beginPacket(ctx.udp->remoteIP(), ctx.config.udp_port);
-    String response = String(ClusterProtocol::RESPONSE_MSG) + ":" + ctx.hostname;
-    ctx.udp->write(response.c_str());
-    ctx.udp->endPacket();
+// Discovery functionality removed - using heartbeat-only approach
+
+void ClusterManager::onHeartbeat(const char* msg) {
+    // Extract hostname from heartbeat message: "CLUSTER_HEARTBEAT:hostname"
+    const char* colon = strchr(msg, ':');
+    if (!colon) {
+        LOG_WARN("Cluster", "Invalid heartbeat message format");
+        return;
+    }
+
+    String hostname = String(colon + 1);
+    IPAddress senderIP = ctx.udp->remoteIP();
+
+    // Update memberlist with the heartbeat
+    addOrUpdateNode(hostname, senderIP);
+
+    // Respond with minimal node info (hostname, ip, uptime, labels)
+    sendNodeInfo(hostname, senderIP);
 }
 
-void ClusterManager::onHeartbeat(const char* /*msg*/) {
+void ClusterManager::onNodeUpdate(const char* msg) {
+    // Message format: "NODE_UPDATE:hostname:{json}"
+    const char* firstColon = strchr(msg, ':');
+    if (!firstColon) {
+        LOG_WARN("Cluster", "Invalid NODE_UPDATE message format");
+        return;
+    }
+
+    const char* secondColon = strchr(firstColon + 1, ':');
+    if (!secondColon) {
+        LOG_WARN("Cluster", "Invalid NODE_UPDATE message format");
+        return;
+    }
+
+    String hostnamePart = String(firstColon + 1);
+    String hostname = hostnamePart.substring(0, secondColon - firstColon - 1);
+    const char* jsonCStr = secondColon + 1;
+
+    JsonDocument doc;
+    DeserializationError err = deserializeJson(doc, jsonCStr);
+    if (err) {
+        LOG_WARN("Cluster", String("Failed to parse NODE_UPDATE JSON from ") + ctx.udp->remoteIP().toString());
+        return;
+    }
+
+    // The NODE_UPDATE contains info about the target node (hostname from message)
+    // but is sent FROM the responding node (ctx.udp->remoteIP())
+    // We need to find the responding node in the memberlist, not the target node
+    IPAddress respondingNodeIP = ctx.udp->remoteIP();
+    auto& memberList = *ctx.memberList;
+
+    // Find the responding node by IP address
+    NodeInfo* respondingNode = nullptr;
+    for (auto& pair : memberList) {
+        if (pair.second.ip == respondingNodeIP) {
+            respondingNode = &pair.second;
+            break;
+        }
+    }
+
+    if (respondingNode) {
+        // Calculate latency only if we recently sent a heartbeat (within last 1 second)
+        unsigned long latency = 0;
+        unsigned long now = millis();
+        if (lastHeartbeatSentAt != 0 && (now - lastHeartbeatSentAt) < 1000) { // 1 second window
+            latency = now - lastHeartbeatSentAt;
+            lastHeartbeatSentAt = 0; // Reset for next calculation
+        }
+
+        // Update the responding node's information
+        bool hostnameChanged = false;
+        if (doc["hostname"].is<const char*>()) {
+            String newHostname = doc["hostname"].as<const char*>();
+            if (respondingNode->hostname != newHostname) {
+                respondingNode->hostname = newHostname;
+                hostnameChanged = true;
+            }
+        }
+
+        if (doc["uptime"].is<unsigned long>()) {
+            respondingNode->uptime = doc["uptime"];
+        }
+
+        // Update labels if provided
+        bool labelsChanged = false;
+        if (doc["labels"].is<JsonObject>()) {
+            // Check if labels actually changed
+            JsonObject labelsObj = doc["labels"].as<JsonObject>();
+            std::map<String, String> newLabels;
+            for (JsonPair kvp : labelsObj) {
+                const char* key = kvp.key().c_str();
+                const char* value = labelsObj[kvp.key()];
+                newLabels[key] = String(value);
+            }
+
+            // Compare with existing labels
+            if (newLabels != respondingNode->labels) {
+                labelsChanged = true;
+                respondingNode->labels = newLabels;
+            }
+        }
+
+        respondingNode->lastSeen = now;
+        respondingNode->status = NodeInfo::ACTIVE;
+
+        // Update latency if we calculated it (preserve existing value if not)
+        if (latency > 0) {
+            respondingNode->latency = latency;
+        }
+
+        // Check if any fields changed that require broadcasting
+        bool nodeInfoChanged = hostnameChanged || labelsChanged;
+
+        if (nodeInfoChanged) {
+            // Fire cluster/node/update event to trigger broadcast
+            ctx.fire("cluster/node/update", nullptr);
+        }
+
+        LOG_DEBUG("Cluster", String("Updated responding node ") + respondingNode->hostname + " @ " + respondingNodeIP.toString() +
+                 " | hostname: " + (hostnameChanged ? "changed" : "unchanged") +
+                 " | labels: " + (labelsChanged ? "changed" : "unchanged") +
+                 " | latency: " + (latency > 0 ? String(latency) + "ms" : "not calculated"));
+    } else {
+        LOG_WARN("Cluster", String("Received NODE_UPDATE from unknown node: ") + respondingNodeIP.toString());
+    }
+}
+
+void ClusterManager::sendNodeInfo(const String& targetHostname, const IPAddress& targetIP) {
     JsonDocument doc;
 
-    if (ctx.memberList) {
-        auto it = ctx.memberList->find(ctx.hostname);
-        if (it != ctx.memberList->end()) {
+    // Get our node info for the response (we're the responding node)
+    auto& memberList = *ctx.memberList;
+    auto it = memberList.find(ctx.hostname);
+    if (it != memberList.end()) {
+        const NodeInfo& node = it->second;
+
+        // Response contains info about ourselves (the responding node)
+        doc["hostname"] = node.hostname;
+        doc["ip"] = node.ip.toString();
+        doc["uptime"] = node.uptime;
+
+        // Add labels if present
+        if (!node.labels.empty()) {
             JsonObject labelsObj = doc["labels"].to<JsonObject>();
-            for (const auto& kv : it->second.labels) {
-                labelsObj[kv.first.c_str()] = kv.second;
-            }
-        } else if (!ctx.self.labels.empty()) {
-            JsonObject labelsObj = doc["labels"].to<JsonObject>();
-            for (const auto& kv : ctx.self.labels) {
+            for (const auto& kv : node.labels) {
                 labelsObj[kv.first.c_str()] = kv.second;
             }
         }
+    } else {
+        // Fallback to basic info
+        doc["hostname"] = ctx.hostname;
+        doc["ip"] = ctx.localIP.toString();
+        doc["uptime"] = millis();
     }
 
     String json;
     serializeJson(doc, json);
 
-    ctx.udp->beginPacket(ctx.udp->remoteIP(), ctx.config.udp_port);
-    String msg = String(ClusterProtocol::NODE_INFO_MSG) + ":" + ctx.hostname + ":" + json;
+    // Send NODE_UPDATE:targetHostname:{json about responding node}
+    ctx.udp->beginPacket(targetIP, ctx.config.udp_port);
+    String msg = String(ClusterProtocol::NODE_UPDATE_MSG) + ":" + targetHostname + ":" + json;
     ctx.udp->write(msg.c_str());
     ctx.udp->endPacket();
-}
 
-void ClusterManager::onResponse(const char* msg) {
-    char* hostPtr = const_cast<char*>(msg) + strlen(ClusterProtocol::RESPONSE_MSG) + 1;
-    String nodeHost = String(hostPtr);
-    addOrUpdateNode(nodeHost, ctx.udp->remoteIP());
-}
-
-void ClusterManager::onNodeInfo(const char* msg) {
-    char* p = const_cast<char*>(msg) + strlen(ClusterProtocol::NODE_INFO_MSG) + 1;
-    char* hostEnd = strchr(p, ':');
-    if (hostEnd) {
-        *hostEnd = '\0';
-        const char* hostCStr = p;
-        const char* jsonCStr = hostEnd + 1;
-
-        String nodeHost = String(hostCStr);
-        IPAddress senderIP = ctx.udp->remoteIP();
-
-        addOrUpdateNode(nodeHost, senderIP);
-
-        JsonDocument doc;
-        DeserializationError err = deserializeJson(doc, jsonCStr);
-        if (!err) {
-            auto& memberList = *ctx.memberList;
-            auto it = memberList.find(nodeHost);
-            if (it != memberList.end()) {
-                NodeInfo& node = it->second;
-                node.status = NodeInfo::ACTIVE;
-                unsigned long now = millis();
-                node.lastSeen = now;
-                if (lastHeartbeatSentAt != 0) {
-                    node.latency = now - lastHeartbeatSentAt;
-                }
-
-                node.labels.clear();
-                if (doc["labels"].is<JsonObject>()) {
-                    JsonObject labelsObj = doc["labels"].as<JsonObject>();
-                    for (JsonPair kvp : labelsObj) {
-                        const char* key = kvp.key().c_str();
-                        const char* value = labelsObj[kvp.key()];
-                        node.labels[key] = value;
-                    }
-                }
-            }
-        } else {
-            LOG_WARN("Cluster", String("Failed to parse NODE_INFO JSON from ") + senderIP.toString());
-        }
-    }
+    LOG_DEBUG("Cluster", String("Sent NODE_UPDATE response to ") + targetHostname + " @ " + targetIP.toString());
 }
 
 void ClusterManager::onClusterEvent(const char* msg) {
@@ -269,26 +346,36 @@ void ClusterManager::onRawMessage(const char* msg) {
 
 void ClusterManager::addOrUpdateNode(const String& nodeHost, IPAddress nodeIP) {
     auto& memberList = *ctx.memberList;
-    
+    bool memberlistChanged = false;
+
     // O(1) lookup instead of O(n) search
     auto it = memberList.find(nodeHost);
     if (it != memberList.end()) {
-        // Update existing node
-        it->second.ip = nodeIP;
+        // Update existing node - preserve all existing field values
+        if (it->second.ip != nodeIP) {
+            it->second.ip = nodeIP;
+            memberlistChanged = true;
+        }
         it->second.lastSeen = millis();
+        // Note: Other fields like latency, uptime, labels, etc. are preserved
+        //fetchNodeInfo(nodeIP); // Do not fetch here, handled by periodic task
+    } else {
+        // Add new node
+        NodeInfo newNode;
+        newNode.hostname = nodeHost;
+        newNode.ip = nodeIP;
+        newNode.lastSeen = millis();
+        updateNodeStatus(newNode, newNode.lastSeen, ctx.config.node_inactive_threshold_ms, ctx.config.node_dead_threshold_ms);
+        memberList[nodeHost] = newNode;
+        memberlistChanged = true;
+        LOG_INFO("Cluster", "Added node: " + nodeHost + " @ " + newNode.ip.toString() + " | Status: " + statusToStr(newNode.status) + " | last update: 0");
         //fetchNodeInfo(nodeIP); // Do not fetch here, handled by periodic task
-        return;
     }
-    
-    // Add new node
-    NodeInfo newNode;
-    newNode.hostname = nodeHost;
-    newNode.ip = nodeIP;
-    newNode.lastSeen = millis();
-    updateNodeStatus(newNode, newNode.lastSeen, ctx.config.node_inactive_threshold_ms, ctx.config.node_dead_threshold_ms);
-    memberList[nodeHost] = newNode;
-    LOG_INFO("Cluster", "Added node: " + nodeHost + " @ " + newNode.ip.toString() + " | Status: " + statusToStr(newNode.status) + " | last update: 0");
-    //fetchNodeInfo(nodeIP); // Do not fetch here, handled by periodic task
+
+    // Fire event if memberlist changed
+    if (memberlistChanged) {
+        ctx.fire("cluster/memberlist/changed", nullptr);
+    }
 }
 
 // unused http client to fetch complete node info
@@ -406,16 +493,19 @@ void ClusterManager::heartbeatTaskCallback() {
         NodeInfo& node = it->second;
         node.lastSeen = millis();
         node.status = NodeInfo::ACTIVE;
+        node.uptime = millis(); // Update uptime
         updateLocalNodeResources();
         addOrUpdateNode(ctx.hostname, ctx.localIP);
     }
 
-    // Broadcast heartbeat so peers can respond with their node info
+    // Broadcast heartbeat - peers will respond with NODE_UPDATE
     lastHeartbeatSentAt = millis();
     ctx.udp->beginPacket("255.255.255.255", ctx.config.udp_port);
     String hb = String(ClusterProtocol::HEARTBEAT_MSG) + ":" + ctx.hostname;
     ctx.udp->write(hb.c_str());
     ctx.udp->endPacket();
+
+    LOG_DEBUG("Cluster", String("Sent heartbeat: ") + ctx.hostname);
 }
 
 void ClusterManager::updateAllMembersInfoTaskCallback() {
@@ -423,6 +513,40 @@ void ClusterManager::updateAllMembersInfoTaskCallback() {
     // No-op to reduce network and memory usage
 }
 
+void ClusterManager::broadcastNodeUpdate() {
+    // Broadcast our current node info as NODE_UPDATE to all cluster members
+    auto& memberList = *ctx.memberList;
+    auto it = memberList.find(ctx.hostname);
+    if (it == memberList.end()) {
+        return;
+    }
+
+    const NodeInfo& node = it->second;
+
+    JsonDocument doc;
+    doc["hostname"] = node.hostname;
+    doc["uptime"] = node.uptime;
+
+    // Add labels if present
+    if (!node.labels.empty()) {
+        JsonObject labelsObj = doc["labels"].to<JsonObject>();
+        for (const auto& kv : node.labels) {
+            labelsObj[kv.first.c_str()] = kv.second;
+        }
+    }
+
+    String json;
+    serializeJson(doc, json);
+
+    // Broadcast to all cluster members
+    ctx.udp->beginPacket("255.255.255.255", ctx.config.udp_port);
+    String msg = String(ClusterProtocol::NODE_UPDATE_MSG) + ":" + ctx.hostname + ":" + json;
+    ctx.udp->write(msg.c_str());
+    ctx.udp->endPacket();
+
+    LOG_DEBUG("Cluster", String("Broadcasted NODE_UPDATE for ") + ctx.hostname);
+}
+
 void ClusterManager::updateAllNodeStatuses() {
     auto& memberList = *ctx.memberList;
     unsigned long now = millis();
@@ -435,17 +559,24 @@ void ClusterManager::updateAllNodeStatuses() {
 void ClusterManager::removeDeadNodes() {
     auto& memberList = *ctx.memberList;
     unsigned long now = millis();
-    
+    bool memberlistChanged = false;
+
     // Use iterator to safely remove elements from map
     for (auto it = memberList.begin(); it != memberList.end(); ) {
         unsigned long diff = now - it->second.lastSeen;
         if (it->second.status == NodeInfo::DEAD && diff > ctx.config.node_dead_threshold_ms) {
             LOG_INFO("Cluster", "Removing node: " + it->second.hostname);
             it = memberList.erase(it);
+            memberlistChanged = true;
         } else {
             ++it;
         }
     }
+
+    // Fire event if memberlist changed
+    if (memberlistChanged) {
+        ctx.fire("cluster/memberlist/changed", nullptr);
+    }
 }
 
 void ClusterManager::printMemberList() {

src/spore/core/NetworkManager.cpp

@@ -128,5 +128,5 @@ void NetworkManager::setupWiFi() {
     }
 
     // Notify listeners that the node is (re)discovered
-    ctx.fire("node_discovered", &ctx.self);
+    ctx.fire("node/discovered", &ctx.self);
 }

src/spore/services/NodeService.cpp

@@ -255,12 +255,9 @@ void NodeService::handleGetConfigRequest(AsyncWebServerRequest* request) {
     
     // Cluster Configuration
     JsonObject clusterObj = doc["cluster"].to<JsonObject>();
-    clusterObj["discovery_interval_ms"] = ctx.config.discovery_interval_ms;
     clusterObj["heartbeat_interval_ms"] = ctx.config.heartbeat_interval_ms;
     clusterObj["cluster_listen_interval_ms"] = ctx.config.cluster_listen_interval_ms;
     clusterObj["status_update_interval_ms"] = ctx.config.status_update_interval_ms;
-    clusterObj["member_info_update_interval_ms"] = ctx.config.member_info_update_interval_ms;
-    clusterObj["print_interval_ms"] = ctx.config.print_interval_ms;
     
     // Node Status Thresholds
     JsonObject thresholdsObj = doc["thresholds"].to<JsonObject>();

src/spore/types/Config.cpp

@@ -32,12 +32,9 @@ void Config::setDefaults() {
     api_server_port = DEFAULT_API_SERVER_PORT;
     
     // Cluster Configuration
-    discovery_interval_ms = DEFAULT_DISCOVERY_INTERVAL_MS; // TODO retire this in favor of heartbeat_interval_ms
     cluster_listen_interval_ms = DEFAULT_CLUSTER_LISTEN_INTERVAL_MS;
     heartbeat_interval_ms = DEFAULT_HEARTBEAT_INTERVAL_MS;
     status_update_interval_ms = DEFAULT_STATUS_UPDATE_INTERVAL_MS;
-    member_info_update_interval_ms = DEFAULT_MEMBER_INFO_UPDATE_INTERVAL_MS; // TODO retire this in favor of heartbeat_interval_ms
-    print_interval_ms = DEFAULT_PRINT_INTERVAL_MS;
     
     // Node Status Thresholds
     node_active_threshold_ms = DEFAULT_NODE_ACTIVE_THRESHOLD_MS;
@@ -86,12 +83,9 @@ bool Config::saveToFile(const String& filename) {
     doc["network"]["api_server_port"] = api_server_port;
     
     // Cluster Configuration
-    doc["cluster"]["discovery_interval_ms"] = discovery_interval_ms;
     doc["cluster"]["heartbeat_interval_ms"] = heartbeat_interval_ms;
     doc["cluster"]["cluster_listen_interval_ms"] = cluster_listen_interval_ms;
     doc["cluster"]["status_update_interval_ms"] = status_update_interval_ms;
-    doc["cluster"]["member_info_update_interval_ms"] = member_info_update_interval_ms;
-    doc["cluster"]["print_interval_ms"] = print_interval_ms;
     
     // Node Status Thresholds
     doc["thresholds"]["node_active_threshold_ms"] = node_active_threshold_ms;
@@ -166,12 +160,9 @@ bool Config::loadFromFile(const String& filename) {
     api_server_port = doc["network"]["api_server_port"] | DEFAULT_API_SERVER_PORT;
     
     // Load Cluster Configuration with defaults
-    discovery_interval_ms = doc["cluster"]["discovery_interval_ms"] | DEFAULT_DISCOVERY_INTERVAL_MS;
     heartbeat_interval_ms = doc["cluster"]["heartbeat_interval_ms"] | DEFAULT_HEARTBEAT_INTERVAL_MS;
     cluster_listen_interval_ms = doc["cluster"]["cluster_listen_interval_ms"] | DEFAULT_CLUSTER_LISTEN_INTERVAL_MS;
     status_update_interval_ms = doc["cluster"]["status_update_interval_ms"] | DEFAULT_STATUS_UPDATE_INTERVAL_MS;
-    member_info_update_interval_ms = doc["cluster"]["member_info_update_interval_ms"] | DEFAULT_MEMBER_INFO_UPDATE_INTERVAL_MS;
-    print_interval_ms = doc["cluster"]["print_interval_ms"] | DEFAULT_PRINT_INTERVAL_MS;
     
     // Load Node Status Thresholds with defaults
     node_active_threshold_ms = doc["thresholds"]["node_active_threshold_ms"] | DEFAULT_NODE_ACTIVE_THRESHOLD_MS;