New feature for REST API: one can trigger reload of a plugin configuration via PUT request

README.md

@@ -129,7 +129,7 @@ Tables with allowed ressources sorted by REST methods can be found below. A quer
 
 | Ressource | Explanation |
 |:--------- |:----------- |
-| /[plugin]/[action] | One can request to do a action on the specified plugin. Currently supported actions are `start` and `stop` which start or stop the polling of the sensors of the plugin.
+| /[plugin]/[action] | One can request to do a action on the specified plugin. Currently supported actions are `start`, `stop` and `reload` which start or stop the polling of the sensors of the plugin respectively triggers a reload of the plugin configuration. If a configuration reload is requested, all sensors of the plugin are stopped first. Then new sensors are created and started according to the configuration.
 
 
 ### Examples

src/Configurator.h

@@ -20,19 +20,42 @@ typedef struct {
 } pluginSettings_t;
 
 /**
- * Abstract base class, which defines the interface for the configurators in the shared dynamic libraries.
+ * Base class, which defines the interface for the configurators in the shared dynamic libraries.
+ * This base class shall not be constructed on itw own.
  */
 class Configurator {
 public:
 	Configurator() : _cacheInterval(900000) {}
-	virtual ~Configurator() {}
+
+	virtual ~Configurator() {
+		for (auto s : _sensors) {
+			delete s;
+		}
+	}
 
 	/**
 	 * Read in the given configuration
 	 * @param	cfgPath Path to the config-file
 	 * @return	true on success, false otherwise
 	 */
-	virtual bool readConfig(std::string cfgPath) = 0;
+	virtual bool readConfig(std::string cfgPath) {
+		_cfgPath = cfgPath;
+		return true;
+	}
+
+	/**
+	 * Clear internal storage and read in the configuration again.
+	 */
+	virtual bool reReadConfig() {
+		for (auto s : _sensors) {
+			s->stopPolling();
+		}
+		for (auto s : _sensors) {
+			delete s;
+		}
+		_sensors.clear();
+		return this->readConfig(_cfgPath);
+	}
 
 	virtual void setGlobalSettings(const pluginSettings_t& pluginSettings) {
 		_mqttPrefix = pluginSettings.mqttPrefix;
@@ -44,6 +67,7 @@ public:
 	}
 
 protected:
+	std::string _cfgPath;
 	std::string _mqttPrefix;
 	unsigned int _cacheInterval;
 	std::vector<Sensor*> _sensors;

src/HttpsServer.cpp

@@ -227,36 +227,68 @@ void HttpsServer::requestHandler::operator()(server::request const &request, ser
 			goto error;
 		}
 
-		//check if query and action are valid values
-		if (pathStrs[1] != "start" && pathStrs[1] != "stop") {
-			LOGH(warning) << "Unknown action " << pathStrs[1] << " requested";
-			connection->set_status(server::connection::not_supported);
-			goto error;
-		}
-
 		std::string action = pathStrs[1];
 
 		//process actual request
 		response = "Plugin not found!";
 		connection->set_status(server::connection::not_found);
 
-		for(auto& p : _httpsServer._plugins) {
-			if (p.id == pathStrs[0]) {
-				if (action == "start") {
+		//switch code depending on selected action
+		if (action == "start") {
+			for(auto& p : _httpsServer._plugins) {
+				if (p.id == pathStrs[0]) {
 					for(auto s : p.configurator->getSensors()) {
 						s->startPolling();
 					}
 					response = "Plugin " + pathStrs[0] + ": Sensors started";
 					connection->set_status(server::connection::ok);
-				} else if (action == "stop") {
+					break;
+				}
+			}
+		} else if (action == "stop") {
+			for(auto& p : _httpsServer._plugins) {
+				if (p.id == pathStrs[0]) {
 					for(auto s : p.configurator->getSensors()) {
 						s->stopPolling();
 					}
 					response = "Plugin " + pathStrs[0] + ": Sensors stopped";
 					connection->set_status(server::connection::ok);
+					break;
 				}
-				break;
 			}
+		} else if (action == "reload") {
+			for(auto& p : _httpsServer._plugins) {
+				if (p.id == pathStrs[0]) {
+					//before modifying the plugin we need to ensure that we have exclusive access
+					//therefore pause the only other concurrent user (MQTTPusher)
+					_httpsServer._mqttPusher->halt();
+					//wait until MQTTPusher is paused
+					while (!_httpsServer._mqttPusher->isHalted()) {
+						sleep(1);
+					}
+
+					if (p.configurator->reReadConfig()) {
+						response = "Plugin " + pathStrs[0] + ": Configuration reloaded";
+						connection->set_status(server::connection::ok);
+					} else {
+						response = "Plugin " + pathStrs[0] + ": Could not reload configuration";
+						connection->set_status(server::connection::internal_server_error);
+					}
+
+					for(auto s : p.configurator->getSensors()) {
+						s->init(_httpsServer._io);
+						s->startPolling();
+					}
+
+					//continue MQTTPusher
+					_httpsServer._mqttPusher->cont();
+					break;
+				}
+			}
+		} else {
+			LOGH(warning) << "Unknown action " << pathStrs[1] << " requested";
+			connection->set_status(server::connection::not_supported);
+			goto error;
 		}
 	}
 
@@ -275,8 +307,8 @@ void HttpsServer::requestHandler::log(const server::string_type& message) {
 	LOGH(error) << message;
 }
 
-HttpsServer::HttpsServer(restAPISettings_t restAPISettings, pluginVector_t& plugins) :
-		_plugins(plugins), _handler(*this) {
+HttpsServer::HttpsServer(restAPISettings_t restAPISettings, pluginVector_t& plugins, MQTTPusher* mqttPusher, boost::asio::io_service& io) :
+		_plugins(plugins), _mqttPusher(mqttPusher), _io(io), _handler(*this) {
 
 	std::shared_ptr<asio::ssl::context> ctx = std::make_shared<asio::ssl::context>(asio::ssl::context::sslv23);
 	ctx->set_options(asio::ssl::context::default_workarounds | asio::ssl::context::no_sslv3 | asio::ssl::context::single_dh_use);

src/HttpsServer.h

@@ -20,8 +20,11 @@
 #include <asio.hpp>
 #include <asio/ssl.hpp>
 
+#include <boost/asio.hpp>
+
 #include "Logging.h"
 #include "PluginDefinitions.h"
+#include "MQTTPusher.h"
 
 typedef struct {
 	std::string restHost;
@@ -44,7 +47,7 @@ typedef std::map<std::string, std::bitset<NUM_PERMISSIONS>> authkeyMap_t;
 class HttpsServer {
 
 public:
-	HttpsServer(restAPISettings_t restAPISettings, pluginVector_t& plugins);
+	HttpsServer(restAPISettings_t restAPISettings, pluginVector_t& plugins, MQTTPusher* mqttPusher, boost::asio::io_service& io);
 	virtual ~HttpsServer();
 
 	bool addAuthkey(authkeyMap_t::value_type authkey) {
@@ -75,7 +78,7 @@ private:
 		void log(const server::string_type& message);
 
 	private:
-		HttpsServer& _httpsServer; //to remember who is our parent. We need access to its _plugins
+		HttpsServer& _httpsServer; //to remember who is our parent. We need access to its member variables (like _plugins)
 		boost::log::sources::severity_logger<boost::log::trivial::severity_level> lg;
 	};
 
@@ -94,6 +97,8 @@ private:
 
 	pluginVector_t& _plugins;
 	authkeyMap_t _authkeys;
+	MQTTPusher* _mqttPusher;
+	boost::asio::io_service& _io;
 
 	server*	_server;
 	requestHandler	_handler;

src/MQTTPusher.cpp

@@ -18,7 +18,9 @@ MQTTPusher::MQTTPusher(int brokerPort, const std::string& brokerHost,
 		_brokerHost(brokerHost),
 		_plugins(plugins),
 		_connected(false),
-		_keepRunning(true) {
+		_keepRunning(true),
+		_doHalt(false),
+		_halted(false) {
 
 	//first print some info
 	int mosqMajor, mosqMinor, mosqRevision;
@@ -73,6 +75,12 @@ void MQTTPusher::push() {
 	reading_t* reads = new reading_t[1024];
 	std::size_t totalCount = 0;
 	while (_keepRunning || totalCount) {
+		if (_doHalt) {
+			_halted = true;
+			sleep(2);
+			continue;
+		}
+		_halted = false;
 		totalCount = 0;
 		for(auto& p : _plugins) {
 			for(auto s : p.configurator->getSensors()) {
@@ -117,6 +125,10 @@ void MQTTPusher::push() {
 						}
 					}
 				}
+				if(_doHalt) {
+					//for faster response
+					continue;
+				}
 			}
 		}
 		sleep(1);

src/MQTTPusher.h

@@ -8,7 +8,7 @@
 #ifndef MQTTPUSHER_H_
 #define MQTTPUSHER_H_
 
-#include "Configuration.h"
+#include "PluginDefinitions.h"
 #include <mosquitto.h>
 
 /**
@@ -30,6 +30,18 @@ public:
 		_keepRunning = false;
 	}
 
+	void halt() {
+		_doHalt = true;
+	}
+
+	void cont() {
+		_doHalt = false;
+	}
+
+	bool isHalted() const {
+		return _halted;
+	}
+
 private:
 	int _brokerPort;
 	std::string _brokerHost;
@@ -37,6 +49,8 @@ private:
 	struct mosquitto* _mosq;
 	bool _connected;
 	bool _keepRunning;
+	bool _doHalt;
+	bool _halted;
 
 	boost::log::sources::severity_logger<boost::log::trivial::severity_level> lg;
 };

src/dcdbpusher.cpp

@@ -349,7 +349,7 @@ int main(int argc, char** argv) {
 
 	//MQTTPusher and Https server get their own threads
 	_mqttPusher = new MQTTPusher(globalSettings.brokerPort, globalSettings.brokerHost, pluginSettings.mqttPrefix, _configuration->getPlugins());
-	_httpsServer = new HttpsServer(restAPISettings, _configuration->getPlugins());
+	_httpsServer = new HttpsServer(restAPISettings, _configuration->getPlugins(), _mqttPusher, io);
 	_configuration->readAuthkeys(_httpsServer);
 
 	boost::thread mqttThread(bind(&MQTTPusher::push, _mqttPusher));

src/sensors/bacnet/BACnetConfigurator.cpp

@@ -18,13 +18,11 @@ BACnetConfigurator::BACnetConfigurator() {
 }
 
 BACnetConfigurator::~BACnetConfigurator() {
-	for(auto s : _sensors) {
-		delete s;
-	}
 	delete _bacClient;
 }
 
 bool BACnetConfigurator::readConfig(std::string cfgPath) {
+	Configurator::readConfig(cfgPath);
 	boost::property_tree::iptree cfg;
 	boost::property_tree::read_info(cfgPath, cfg);
 

src/sensors/bacnet/BACnetConfigurator.h

@@ -34,6 +34,17 @@ public:
 	 */
 	bool readConfig(std::string cfgPath);
 
+	//Overwrite from Configurator
+	bool reReadConfig() {
+		for (auto s : _sensors) {
+			s->stopPolling();
+		}
+		delete _bacClient;
+		_bacClient = NULL;
+		_templateSensors.clear();
+		return Configurator::reReadConfig();
+	}
+
 private:
 	/**
 	 * Set the variables of sensor according to the values specified in config.

src/sensors/ipmi/IPMIConfigurator.cpp

@@ -22,13 +22,11 @@ IPMIConfigurator::IPMIConfigurator() {
 	_globalHost.retransmissionTimeout = 0;
 }
 
-IPMIConfigurator::~IPMIConfigurator() {
-	for (auto s : _sensors) {
-		delete s;
-	}
-}
+IPMIConfigurator::~IPMIConfigurator() {}
 
 bool IPMIConfigurator::readConfig(std::string cfgPath) {
+	Configurator::readConfig(cfgPath);
+
 	boost::property_tree::iptree cfg;
 	boost::property_tree::read_info(cfgPath, cfg);
 

src/sensors/ipmi/IPMIConfigurator.h

@@ -36,11 +36,21 @@ namespace DCDB {
 		bool readConfig(std::string cfgPath);
 
 		//Overwrite from Configurator
-		virtual void setGlobalSettings(const pluginSettings_t& pluginSettings) {
+		void setGlobalSettings(const pluginSettings_t& pluginSettings) {
 			Configurator::setGlobalSettings(pluginSettings);
 			_tempdir = pluginSettings.tempdir;
 		}
 
+		//Overwrite from Configurator
+		bool reReadConfig() {
+			for (auto s : _sensors) {
+				s->stopPolling();
+			}
+			_hosts.clear();
+			_templateSensors.clear();
+			return Configurator::reReadConfig();
+		}
+
 	private:
 		/**
 		 * Set the variables of sensor according to the values specified in config.

src/sensors/ipmi/IPMIHost.cpp

@@ -41,8 +41,7 @@ IPMIHost::IPMIHost(const std::string& hostName, uint32_t retransmissionTimeout,
 	_delayNextReadUntil = 0;
 }
 
-IPMIHost::~IPMIHost() {
-}
+IPMIHost::~IPMIHost() {}
 
 int IPMIHost::connect() {
 	if (!(_ipmiCtx = ipmi_ctx_create())) {

src/sensors/pdu/PDUConfigurator.cpp

@@ -18,16 +18,13 @@ using namespace std;
 
 PDUConfigurator::PDUConfigurator() {
 	// TODO Auto-generated constructor stub
-
 }
 
-PDUConfigurator::~PDUConfigurator() {
-	for (auto s : _sensors) {
-		delete s;
-	}
-}
+PDUConfigurator::~PDUConfigurator() {}
 
 bool PDUConfigurator::readConfig(std::string cfgPath) {
+	Configurator::readConfig(cfgPath);
+
 	boost::property_tree::iptree cfg;
 	boost::property_tree::read_info(cfgPath, cfg);
 

src/sensors/pdu/PDUConfigurator.h

@@ -34,6 +34,16 @@ public:
 	 */
 	bool readConfig(std::string cfgPath);
 
+	//Overwrite from Configurator
+	bool reReadConfig() {
+		for (auto s : _sensors) {
+			s->stopPolling();
+		}
+		_pdus.clear();
+		_templateSensors.clear();
+		return Configurator::reReadConfig();
+	}
+
 private:
 	/**
 	 * Set the variables of sensor according to the values specified in config.

src/sensors/perfevent/PerfeventConfigurator.cpp

@@ -56,14 +56,10 @@ PerfeventConfigurator::PerfeventConfigurator() {
 	//TODO set up map for rest of config enum
 }
 
-PerfeventConfigurator::~PerfeventConfigurator() {
-	for(auto s : _sensors) {
-		delete s;
-	}
-}
+PerfeventConfigurator::~PerfeventConfigurator() {}
 
 bool PerfeventConfigurator::readConfig(std::string cfgPath) {
-	//read template counters
+	Configurator::readConfig(cfgPath);
 
 	boost::property_tree::iptree cfg;
 	boost::property_tree::read_info(cfgPath, cfg);
@@ -88,6 +84,7 @@ bool PerfeventConfigurator::readConfig(std::string cfgPath) {
 		}
 	}
 
+	//read template counters
 	BOOST_FOREACH(boost::property_tree::iptree::value_type &counter, cfg.get_child("CounterTemplate")) {
 		if (boost::iequals(counter.first, "counter")) {
 			LOG(debug) << "Template Counter \"" << counter.second.data() << "\"";

src/sensors/perfevent/PerfeventConfigurator.h

@@ -34,6 +34,13 @@ public:
 	 */
 	bool readConfig(std::string cfgPath);
 
+	//Overwrite from Configurator
+	bool reReadConfig() {
+		_templateCounters.clear();
+		_templateCpus.clear();
+		return Configurator::reReadConfig();
+	}
+
 private:
 	/**
 	 * Set the variables of counter according to the values specified in config.

src/sensors/sysfs/SysfsConfigurator.cpp

@@ -14,17 +14,13 @@
 
 using namespace std;
 
-SysfsConfigurator::SysfsConfigurator() {
+SysfsConfigurator::SysfsConfigurator() {}
 
-}
-
-SysfsConfigurator::~SysfsConfigurator() {
-	for(auto s : _sensors) {
-		delete s;
-	}
-}
+SysfsConfigurator::~SysfsConfigurator() {}
 
 bool SysfsConfigurator::readConfig(std::string cfgPath) {
+	Configurator::readConfig(cfgPath);
+
 	boost::property_tree::iptree cfg;
 	boost::property_tree::read_info(cfgPath, cfg);
 

src/sensors/sysfs/SysfsConfigurator.h

@@ -31,6 +31,12 @@ public:
 	 */
 	bool readConfig(std::string cfgPath);
 
+	//Overwrite from Configurator
+	bool reReadConfig() {
+		_templateSensors.clear();
+		return Configurator::reReadConfig();
+	}
+
 private:
 	/**
 	 * Set the variables of sensor according to the values specified in config.