shard session_store

session_store.hpp

@@ -8,20 +8,27 @@
 #include <array>
 #include <chrono>
 #include <optional>
+#include <atomic>
+#include <list>
 
 class SessionStore {
 private:
 	static constexpr size_t SHARD_COUNT = 16;
+	static constexpr size_t MAX_SESSIONS_PER_SHARD = 64;
+	static constexpr size_t MAX_SESSION_DATA_SIZE = 16;
+	static constexpr size_t MAX_VALUE_SIZE = 1024;
 	static constexpr auto SESSION_TIMEOUT = std::chrono::hours(24);
 
 	struct SessionData {
 		std::unordered_map<std::string, std::string> data;
 		std::chrono::steady_clock::time_point last_access;
+		std::list<std::string>::iterator lru_iter;
 		bool dirty = false;
 	};
 
 	std::array<std::mutex, SHARD_COUNT> mutexes_;
 	std::array<std::unordered_map<std::string, SessionData>, SHARD_COUNT> shards_;
+	std::array<std::list<std::string>, SHARD_COUNT> lru_lists_;
 	KeyValueStore store_;
 	std::mt19937 rng_;
 
@@ -29,24 +36,66 @@ private:
 		return std::hash<std::string>{}(id) % SHARD_COUNT;
 	}
 
+	void evict_lru_session(size_t shard) {
+		auto& shard_map = shards_[shard];
+		auto& lru_list = lru_lists_[shard];
+
+		if (lru_list.empty()) return;
+
+		std::string oldest_id = lru_list.back();
+		lru_list.pop_back();
+
+		auto it = shard_map.find(oldest_id);
+		if (it != shard_map.end()) {
+			// Save dirty session before eviction
+			if (it->second.dirty) {
+				for (const auto& [key, value] : it->second.data) {
+					store_.set(oldest_id + ":" + key, value);
+				}
+			}
+			shard_map.erase(it);
+		}
+	}
+
+	void touch_session(const std::string& id, size_t shard) {
+		auto& session = shards_[shard][id];
+		auto& lru_list = lru_lists_[shard];
+
+		// Move to front of LRU
+		lru_list.erase(session.lru_iter);
+		lru_list.push_front(id);
+		session.lru_iter = lru_list.begin();
+		session.last_access = std::chrono::steady_clock::now();
+	}
+
 	void lazy_load_session(const std::string& id, size_t shard) {
 		auto& shard_map = shards_[shard];
 		if (shard_map.find(id) != shard_map.end()) return;
 
-		// Load from persistent store
+		// Check session limit
+		if (shard_map.size() >= MAX_SESSIONS_PER_SHARD) {
+			evict_lru_session(shard);
+		}
+
 		SessionData session;
 		session.last_access = std::chrono::steady_clock::now();
 
-		// Try to load existing session data
+		// Load from persistent store
 		for (const auto& [key, value] : store_.get_all()) {
 			if (key.starts_with(id + ":")) {
 				std::string session_key = key.substr(id.length() + 1);
 				if (auto* str_val = std::get_if<std::string>(&value)) {
-					session.data[session_key] = *str_val;
+					if (session.data.size() < MAX_SESSION_DATA_SIZE) {
+						session.data[session_key] = *str_val;
+					}
 				}
 			}
 		}
 
+		// Add to LRU
+		lru_lists_[shard].push_front(id);
+		session.lru_iter = lru_lists_[shard].begin();
+
 		shard_map[id] = std::move(session);
 	}
 
@@ -56,9 +105,11 @@ private:
 		for (size_t i = 0; i < SHARD_COUNT; ++i) {
 			std::lock_guard<std::mutex> lock(mutexes_[i]);
 			auto& shard = shards_[i];
+			auto& lru_list = lru_lists_[i];
 
 			for (auto it = shard.begin(); it != shard.end();) {
 				if (now - it->second.last_access > SESSION_TIMEOUT) {
+					lru_list.erase(it->second.lru_iter);
 					it = shard.erase(it);
 				} else {
 					++it;
@@ -73,7 +124,6 @@ public:
 	}
 
 	bool needs_session(const Request& req) const {
-		// Skip sessions for static content
 		if (req.path.starts_with("/static") ||
 		    req.path.starts_with("/assets") ||
 		    req.path.ends_with(".css") ||
@@ -90,7 +140,6 @@ public:
 			return false;
 		}
 
-		// Need sessions for API and admin routes
 		return req.path.starts_with("/api") ||
 		       req.path.starts_with("/admin") ||
 		       req.method == HttpMethod::POST ||
@@ -103,11 +152,21 @@ public:
 		size_t shard = get_shard(id);
 
 		std::lock_guard<std::mutex> lock(mutexes_[shard]);
+
+		// Check session limit
+		if (shards_[shard].size() >= MAX_SESSIONS_PER_SHARD) {
+			evict_lru_session(shard);
+		}
+
 		SessionData session;
 		session.last_access = std::chrono::steady_clock::now();
 		session.dirty = true;
-		shards_[shard][id] = std::move(session);
 
+		// Add to LRU
+		lru_lists_[shard].push_front(id);
+		session.lru_iter = lru_lists_[shard].begin();
+
+		shards_[shard][id] = std::move(session);
 		return id;
 	}
 
@@ -120,21 +179,30 @@ public:
 		auto it = shards_[shard].find(id);
 		if (it == shards_[shard].end()) return std::nullopt;
 
-		it->second.last_access = std::chrono::steady_clock::now();
+		touch_session(id, shard);
+
 		auto data_it = it->second.data.find(key);
 		return data_it != it->second.data.end() ?
 			std::optional<std::string>{data_it->second} : std::nullopt;
 	}
 
 	void set(const std::string& id, const std::string& key, const std::string& value) {
+		if (value.size() > MAX_VALUE_SIZE) return;
+
 		size_t shard = get_shard(id);
 		std::lock_guard<std::mutex> lock(mutexes_[shard]);
 
 		lazy_load_session(id, shard);
 
 		auto& session = shards_[shard][id];
+
+		// Check data limit
+		if (session.data.size() >= MAX_SESSION_DATA_SIZE && session.data.find(key) == session.data.end()) {
+			return;
+		}
+
 		session.data[key] = value;
-		session.last_access = std::chrono::steady_clock::now();
+		touch_session(id, shard);
 		session.dirty = true;
 	}
 
@@ -142,18 +210,20 @@ public:
 		size_t shard = get_shard(id);
 		std::lock_guard<std::mutex> lock(mutexes_[shard]);
 
-		bool found = shards_[shard].erase(id) > 0;
+		auto it = shards_[shard].find(id);
+		if (it == shards_[shard].end()) return false;
+
+		lru_lists_[shard].erase(it->second.lru_iter);
+		shards_[shard].erase(it);
 
 		// Remove from persistent store
-		if (found) {
+		for (const auto& [key, value] : store_.get_all()) {
-			for (const auto& [key, value] : store_.get_all()) {
+			if (key.starts_with(id + ":")) {
-				if (key.starts_with(id + ":")) {
+				store_.del(key);
-					store_.del(key);
-				}
 			}
 		}
 
-		return found;
+		return true;
 	}
 
 	size_t size() {
@@ -171,11 +241,9 @@ public:
 
 	void load() {
 		store_.load();
-		// Sessions loaded lazily on first access
 	}
 
 	void save() {
-		// Save only dirty sessions
 		for (size_t i = 0; i < SHARD_COUNT; ++i) {
 			std::lock_guard<std::mutex> lock(mutexes_[i]);
 
@@ -193,7 +261,6 @@ public:
 		store_.save();
 	}
 
-	// Use existing cookie helpers
 	static std::string_view extract_session_id(const Request& req) {
 		return req.get_cookie("session_id");
 	}