ListDetector - module automatically reloads

modules/listDetector/src/CMakeLists.txt

@@ -1,6 +1,7 @@
 add_executable(listDetector
 	main.cpp
 	configParser.cpp
+	configReloader.cpp
 	csvConfigParser.cpp
 	ipAddressPrefix.cpp
 	rule.cpp

modules/listDetector/src/configReloader.cpp

@@ -0,0 +1,56 @@
+/**
+ * @file
+ * @author Alex Petras <alex.petras@cesnet.cz>
+ * @brief Implementation of the ConfigReloader base class for checking for updates in the
+ * configuration and handling the reloading process
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include "configReloader.hpp"
+
+#include <sys/stat.h>
+#include <unistd.h>
+
+namespace ListDetector {
+
+ConfigReloader::ConfigReloader(char** m_argv)
+	: argv(m_argv)
+{
+}
+
+std::time_t ConfigReloader::getLastModified(const std::string& filePath)
+{
+	struct stat file_stat;
+	if (stat(filePath.c_str(), &file_stat) == 0) {
+		return file_stat.st_mtime;
+	}
+	return -1;
+}
+
+void ConfigReloader::checkReloadConfig(std::string filePath)
+{
+	auto previousTimestamp = getLastModified(filePath);
+	while (true) {
+		sleep(CHECK_INTERVAL);
+		auto currentTimestamp = getLastModified(filePath);
+		if (currentTimestamp != previousTimestamp && currentTimestamp != -1) {
+			previousTimestamp = currentTimestamp;
+
+			this->restart();
+		}
+	}
+}
+
+void ConfigReloader::restart()
+{
+	execv(argv[0], argv);
+}
+
+void ConfigReloader::startThread(std::string filePath)
+{
+	checkConfigThread = std::thread(&ConfigReloader::checkReloadConfig, this, filePath);
+	checkConfigThread.detach();
+}
+
+} // namespace ListDetector

modules/listDetector/src/configReloader.hpp

@@ -0,0 +1,67 @@
+/**
+ * @file
+ * @author Alex Petras <alex.petras@cesnet.cz>
+ * @brief Declaration of the ConfigReloader base class for checking for updates in the configuration
+ * and handling the reloading process
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#pragma once
+
+#include <ctime>
+#include <string>
+#include <thread>
+#include <unistd.h>
+
+namespace ListDetector {
+
+/**
+ * @brief Base class for dealing with reloading the config.
+ *
+ * The `ConfigReloader` class provides functionality for checking for updates in the configuration
+ * and handling the reloading process.
+ */
+class ConfigReloader {
+public:
+	ConfigReloader(char** m_argv);
+
+	/**
+	 * Start a thread that checks for updates in the configuration file.
+	 *
+	 * @param filePath Path to the configuration file to monitor.
+	 */
+	void startThread(std::string filePath);
+
+	/**
+	 * Get the last modified timestamp of a file.
+	 *
+	 * @param filePath Path to the configuration file.
+	 *
+	 * @return The last modified timestamp of the file, or -1 if an error occurred.
+	 */
+	static std::time_t getLastModified(const std::string& filePath);
+
+	/**
+	 * Check for changes in the configuration file and reload if the configuration file has changed.
+	 *
+	 * @param filePath Path to the configuration file to monitor.
+	 */
+	void checkReloadConfig(std::string filePath);
+
+	/**
+	 * Restart the current process with the same arguments effectively reloading the configuration.
+	 */
+	void restart();
+
+	/**
+	 * @brief Interval in seconds to check for file changes.
+	 */
+	static const unsigned int CHECK_INTERVAL = 5;
+
+private:
+	char** argv;
+	std::thread checkConfigThread;
+};
+
+} // namespace ListDetector

modules/listDetector/src/main.cpp

@@ -12,6 +12,7 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
+#include "configReloader.hpp"
 #include "csvConfigParser.hpp"
 #include "listDetector.hpp"
 #include "logger/logger.hpp"
@@ -103,6 +104,15 @@ static void processUnirecRecords(
 
 int main(int argc, char** argv)
 {
+	// make a copy of argv
+	char** argv_copy = new char*[argc + 1];
+	for (int i = 0; i < argc; ++i) {
+		argv_copy[i] = new char[strlen(argv[i]) + 1];
+		argv_copy[argc] = nullptr;
+		strcpy(argv_copy[i], argv[i]);
+	}
+
+	ListDetector::ConfigReloader reloader(argv_copy);
 	argparse::ArgumentParser program("listdetector");
 
 	Nm::loggerInit();
@@ -189,6 +199,7 @@ int main(int argc, char** argv)
 		ListDetector::ListDetector listDetector(configParser.get(), mode);
 		auto listDetectorTelemetryDirectory = telemetryRootDirectory->addDir("listdetector");
 		listDetector.setTelemetryDirectory(listDetectorTelemetryDirectory);
+		reloader.startThread(program.get<std::string>("--rules"));
 
 		processUnirecRecords(biInterface, listDetector);