database header

includes/database_service.hpp

@@ -2,27 +2,34 @@
 #define DATABASE_SERVICE_HPP
 
 #include <boost/asio/io_context.hpp>
+#include <boost/system/detail/error_code.hpp>
 #include <cstddef>
 #include <boost/redis/connection.hpp>
+#include <functional>
 #include <memory>
+#include <mutex>
 
 class DatabaseService {
 public:
     static DatabaseService& getInstance(boost::asio::io_context& io_context, std::size_t pool_size);
-
+    void asyncSetKey(const std::string& key, const std::string& value, std::function<void(boost::system::error_code)> callback);
+    void asyncGetKey(const std::string& key, std::function<void(boost::system::error_code, std::string)> callback); //we could use a varient here for the result
 
 private:    
-    std::shared_ptr<boost::redis::connection> getConnection(); //retrive a connection from the connection pool
-    
     DatabaseService(boost::asio::io_context& io_context, std::size_t pool_size = 4);
     ~DatabaseService();
     DatabaseService(DatabaseService const&);
     void operator=(DatabaseService const&);
 
+    std::shared_ptr<boost::redis::connection> getConnection();
+
     boost::asio::io_context& io_context_;
     std::size_t pool_size_;
     std::vector<std::shared_ptr<boost::redis::connection>> connection_pool_;
     std::size_t current_index_ = 0; //index used for round robin selection
+
+    static DatabaseService* INSTANCE;
+    static std::mutex singleton_mutex;
 };
 
 #endif

src/database_connection.cpp

@@ -1,16 +1,43 @@
 #include "../includes/database_service.hpp"
+#include <boost/redis/connection.hpp>
 #include <cstddef>
+#include <memory>
+#include <mutex>
+#include <stdexcept>
 
+std::mutex DatabaseService::singleton_mutex;
+DatabaseService* DatabaseService::INSTANCE = nullptr;
 
 DatabaseService& DatabaseService::getInstance(boost::asio::io_context &io_context, std::size_t pool_size) {
-    static DatabaseService INSTANCE;
+    std::lock_guard<std::mutex> lock(singleton_mutex);
-    return INSTANCE;
+    if (!INSTANCE) {
+        INSTANCE = new DatabaseService(io_context, pool_size);
+    }
+    return *INSTANCE;
 }
 
-DatabaseService::DatabaseService(boost::asio::io_context& io_context, std::size_t pool_size) : io_context_(io_context), pool_size_(pool_size) {
+DatabaseService::DatabaseService(boost::asio::io_context& io_context, std::size_t pool_size) : io_context_(io_context), pool_size_(pool_size), current_index_(0) {
+    if (pool_size_ <= 0) {
+        throw std::invalid_argument("Connection pool size must be greater than zero.");
+    }
 
+    for (std::size_t i = 0; i < pool_size_; ++i) {
+        auto conn = std::make_shared<boost::redis::connection>(io_context_);
+        connection_pool_.emplace_back(conn);
+    }
 }
 
 DatabaseService::~DatabaseService() {
-
+    connection_pool_.clear();
+}
+
+std::shared_ptr<boost::redis::connection> DatabaseService::getConnection() {
+    std::lock_guard<std::mutex> lock(singleton_mutex);
+    if (connection_pool_.empty()) {
+        throw std::runtime_error("Connection pool is empty.");
+    }
+
+    auto conn = connection_pool_[current_index_];
+    current_index_ = (current_index_ + 1) % pool_size_;
+    return conn; 
 }