feat: introduce udp state machine

include/spore/core/ClusterManager.h

@@ -7,6 +7,8 @@
 #include <ArduinoJson.h>
 #include <ESP8266HTTPClient.h>
 #include <map>
+#include <vector>
+#include <functional>
 
 class ClusterManager {
 public:
@@ -26,4 +28,22 @@ public:
 private:
     NodeContext& ctx;
     TaskManager& taskManager;
+	enum class ListenState { WAITING_FOR_PACKET, MESSAGE_RECEIVED, DISPATCHING, DONE };
+	struct MessageHandler {
+		bool (*predicate)(const char*);
+		std::function<void(const char*)> handle;
+		const char* name;
+	};
+	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);
+	void onDiscovery(const char* msg);
+	void onHeartbeat(const char* msg);
+	void onResponse(const char* msg);
+	void onNodeInfo(const char* msg);
+	ListenState listenState = ListenState::WAITING_FOR_PACKET;
+	std::vector<MessageHandler> messageHandlers;
 };

src/spore/core/ClusterManager.cpp

@@ -10,6 +10,7 @@ ClusterManager::ClusterManager(NodeContext& ctx, TaskManager& taskMgr) : ctx(ctx
     });
     // Register tasks
     registerTasks();
+    initMessageHandlers();
 }
 
 void ClusterManager::registerTasks() {
@@ -29,28 +30,80 @@ void ClusterManager::sendDiscovery() {
     ctx.udp->endPacket();
 }
 
-// TODO the various if statements here are a mess, we need to clean them up
-// TODO we should use a state machine to handle the different types of messages
-// TODO we should use a class to handle the different types of messages using predicate functions
 void ClusterManager::listenForDiscovery() {
+    switch (listenState) {
+        case ListenState::WAITING_FOR_PACKET: {
             int packetSize = ctx.udp->parsePacket();
             if (packetSize) {
+                listenState = ListenState::MESSAGE_RECEIVED;
+            }
+            break;
+        }
+        case ListenState::MESSAGE_RECEIVED: {
             char incoming[ClusterProtocol::UDP_BUF_SIZE];
             int len = ctx.udp->read(incoming, ClusterProtocol::UDP_BUF_SIZE);
             if (len > 0) {
                 incoming[len] = 0;
+                listenState = ListenState::DISPATCHING;
+                handleIncomingMessage(incoming);
+            } else {
+                listenState = ListenState::DONE;
             }
-        //LOG_DEBUG(ctx, "UDP", "Packet received: " + String(incoming));
+            break;
-        if (strcmp(incoming, ClusterProtocol::DISCOVERY_MSG) == 0) {
+        }
-            //LOG_DEBUG(ctx, "UDP", "Discovery request from: " + ctx.udp->remoteIP().toString());
+        case ListenState::DISPATCHING: {
+            // handled synchronously
+            listenState = ListenState::DONE;
+            break;
+        }
+        case ListenState::DONE: {
+            listenState = ListenState::WAITING_FOR_PACKET;
+            break;
+        }
+    }
+}
+
+void ClusterManager::initMessageHandlers() {
+    messageHandlers.clear();
+    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" });
+}
+
+void ClusterManager::handleIncomingMessage(const char* incoming) {
+    for (const auto& h : messageHandlers) {
+        if (h.predicate(incoming)) {
+            h.handle(incoming);
+            return;
+        }
+    }
+}
+
+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;
+}
+
+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();
-            //LOG_DEBUG(ctx, "UDP", "Sent response with hostname: " + ctx.hostname);
+}
-        } else if (strncmp(incoming, ClusterProtocol::HEARTBEAT_MSG, strlen(ClusterProtocol::HEARTBEAT_MSG)) == 0) {
+
-            // Reply directly to heartbeat sender with our node info JSON
+void ClusterManager::onHeartbeat(const char* /*msg*/) {
-            // Format: CLUSTER_NODE_INFO:<hostname>:<json>
     JsonDocument doc;
     doc["freeHeap"] = ESP.getFreeHeap();
     doc["chipId"] = ESP.getChipId();
@@ -58,7 +111,6 @@ void ClusterManager::listenForDiscovery() {
     doc["cpuFreqMHz"] = ESP.getCpuFreqMHz();
     doc["flashChipSize"] = ESP.getFlashChipSize();
 
-            // Include labels if available
     if (ctx.memberList) {
         auto it = ctx.memberList->find(ctx.hostname);
         if (it != ctx.memberList->end()) {
@@ -81,13 +133,16 @@ void ClusterManager::listenForDiscovery() {
     String msg = String(ClusterProtocol::NODE_INFO_MSG) + ":" + ctx.hostname + ":" + json;
     ctx.udp->write(msg.c_str());
     ctx.udp->endPacket();
-        } else if (strncmp(incoming, ClusterProtocol::RESPONSE_MSG, strlen(ClusterProtocol::RESPONSE_MSG)) == 0) {
+}
-            char* hostPtr = incoming + strlen(ClusterProtocol::RESPONSE_MSG) + 1;
+
+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());
-        } else if (strncmp(incoming, ClusterProtocol::NODE_INFO_MSG, strlen(ClusterProtocol::NODE_INFO_MSG)) == 0) {
+}
-            // Parse: CLUSTER_NODE_INFO:<hostname>:<json>
+
-            char* p = incoming + strlen(ClusterProtocol::NODE_INFO_MSG) + 1;
+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';
@@ -97,10 +152,8 @@ void ClusterManager::listenForDiscovery() {
         String nodeHost = String(hostCStr);
         IPAddress senderIP = ctx.udp->remoteIP();
 
-                // Ensure node exists/updated basic info
         addOrUpdateNode(nodeHost, senderIP);
 
-                // Parse JSON
         JsonDocument doc;
         DeserializationError err = deserializeJson(doc, jsonCStr);
         if (!err) {
@@ -119,7 +172,6 @@ void ClusterManager::listenForDiscovery() {
                 node.status = NodeInfo::ACTIVE;
                 node.lastSeen = millis();
 
-                        // Labels
                 node.labels.clear();
                 if (doc["labels"].is<JsonObject>()) {
                     JsonObject labelsObj = doc["labels"].as<JsonObject>();
@@ -134,8 +186,6 @@ void ClusterManager::listenForDiscovery() {
             LOG_DEBUG("Cluster", String("Failed to parse NODE_INFO JSON from ") + senderIP.toString());
         }
     }
-        }
-    }
 }
 
 void ClusterManager::addOrUpdateNode(const String& nodeHost, IPAddress nodeIP) {