feat: measure latency

include/spore/core/ClusterManager.h

@@ -43,5 +43,6 @@ private:
 	void onHeartbeat(const char* msg);
 	void onResponse(const char* msg);
 	void onNodeInfo(const char* msg);
+	unsigned long lastHeartbeatSentAt = 0;
 	std::vector<MessageHandler> messageHandlers;
 };

include/spore/types/NodeInfo.h

@@ -17,7 +17,7 @@ struct NodeInfo {
         uint32_t cpuFreqMHz = 0;
         uint32_t flashChipSize = 0;
     } resources;
-    unsigned long latency = 0; // ms since lastSeen
+    unsigned long latency = 0; // ms from heartbeat broadcast to NODE_INFO receipt
     std::vector<EndpointInfo> endpoints; // List of registered endpoints
     std::map<String, String> labels; // Arbitrary node labels (key -> value)
 };

src/spore/core/ClusterManager.cpp

@@ -14,12 +14,12 @@ ClusterManager::ClusterManager(NodeContext& ctx, TaskManager& taskMgr) : ctx(ctx
 }
 
 void ClusterManager::registerTasks() {
-    taskManager.registerTask("discovery_send", ctx.config.discovery_interval_ms, [this]() { sendDiscovery(); });
+    taskManager.registerTask("cluster_discovery", ctx.config.discovery_interval_ms, [this]() { sendDiscovery(); });
     taskManager.registerTask("cluster_listen", ctx.config.discovery_interval_ms / 10, [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("update_members_info", ctx.config.member_info_update_interval_ms, [this]() { updateAllMembersInfoTaskCallback(); });
+    taskManager.registerTask("cluster_update_members_info", ctx.config.member_info_update_interval_ms, [this]() { updateAllMembersInfoTaskCallback(); });
     LOG_INFO("ClusterManager", "Registered all cluster tasks");
 }
 
@@ -152,7 +152,11 @@ void ClusterManager::onNodeInfo(const char* msg) {
                 node.resources.cpuFreqMHz = doc["cpuFreqMHz"] | node.resources.cpuFreqMHz;
                 node.resources.flashChipSize = doc["flashChipSize"] | node.resources.flashChipSize;
                 node.status = NodeInfo::ACTIVE;
-                node.lastSeen = millis();
+                unsigned long now = millis();
+                node.lastSeen = now;
+                if (lastHeartbeatSentAt != 0) {
+                    node.latency = now - lastHeartbeatSentAt;
+                }
 
                 node.labels.clear();
                 if (doc["labels"].is<JsonObject>()) {
@@ -313,6 +317,7 @@ void ClusterManager::heartbeatTaskCallback() {
     }
 
     // Broadcast heartbeat so peers can respond with their node info
+    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());