Grafana: REST API request to rebuild the sensor navigator

grafana/GrafanaServer.cpp

@@ -245,7 +245,7 @@ int main(int argc, char *argv[])
 		_configuration->readRestAPIUsers(_httpsServer);
 		
 		LOG(info) << "Retrieving published sensor names and topics...";
-		if(!_httpsServer->initTree()) {
+		if(!_httpsServer->buildTree()) {
 			throw std::runtime_error("Unable to initialize the sensor navigator!");
 		}
 		

grafana/README.md

@@ -148,6 +148,16 @@ Tables with allowed ressources sorted by REST methods can be found below. A quer
 </tr>
 </table>
 
+<table>
+<tr>
+<td colspan="2"><b>PUT /navigator</b></td>
+<td colspan="2">Rebuilds the internal sensor navigator.</td>
+</tr>
+<tr>
+<td colspan="4">No queries.</td>
+</tr>
+</table>
+
 > NOTE &ensp;&ensp;&ensp;&ensp;&ensp; Opt. = Optional
 
 ### Examples <a name="restExamples"></a>

grafana/RestAPI.cpp

@@ -41,6 +41,7 @@ RestAPI::RestAPI(serverSettings_t settings,
                  DCDB::Connection* cassandraConnection) :
                  RESTHttpsServer(settings),
                  _connection(cassandraConnection),
+                 _updating(false),
                  _hierarchySettings(hierarchySettings) {
 
     //Configuring endpoints
@@ -48,54 +49,47 @@ RestAPI::RestAPI(serverSettings_t settings,
     addEndpoint("/levels",      {http::verb::post, stdBind(POST_levels)});
     addEndpoint("/search",      {http::verb::post, stdBind(POST_search)});
     addEndpoint("/query",       {http::verb::post, stdBind(POST_query)});
-}
+    addEndpoint("/navigator",   {http::verb::put, stdBind(PUT_navigator)});
 
-void RestAPI::clear() {
-    if(_sensorConfig) {
-        delete _sensorConfig;
-        _sensorConfig = NULL;
-    }
-    if(_navigator) {
-        delete _navigator;
-        _navigator = NULL;
-    }
-    if(_sensorDataStore) {
-        delete _sensorDataStore;
-        _sensorDataStore = NULL;
-    }
-    _metadataStore.clear();
-    _smootherRegex = boost::regex();
+    _sensorConfig = new DCDB::SensorConfig(_connection);
+    _sensorDataStore = new DCDB::SensorDataStore(_connection);
+    _separator = _hierarchySettings.separator;
+    _smootherRegex = boost::regex(_hierarchySettings.smootherRegex);
+    _numRegex = boost::regex("[0-9]+");
 }
 
 //Initializes the internal sensor navigator
-bool RestAPI::initTree() {
-    clear();
-    
-    //Get the list of all public sensors and topics.
+bool RestAPI::buildTree() {
     std::vector<std::string> topics;
     std::list<DCDB::PublicSensor> publicSensors;
 
-    _sensorConfig = new DCDB::SensorConfig(_connection);
-    _sensorDataStore = new DCDB::SensorDataStore(_connection);
-    if(_sensorConfig->getPublicSensorsVerbose(publicSensors)!=DCDB::SC_OK) {
+    //Spinlock to ensure that only one sensor navigator update runs at a time
+    while(_updating.exchange(true)) {}
+    
+    //Get the list of all public sensors and topics.
+    if(!_sensorConfig || _sensorConfig->getPublicSensorsVerbose(publicSensors)!=DCDB::SC_OK) {
         LOG(error) << "Unable to fetch list of public sensors!";
-        clear();
+        _updating.store(false);
         return false;
     }
+
+    std::shared_ptr<SensorNavigator> newNavigator = std::make_shared<SensorNavigator>();
+    std::shared_ptr<MetadataStore> newMetadataStore = std::make_shared<MetadataStore>();
     
     for(auto& s : publicSensors) {
         topics.push_back(s.pattern);
-        _metadataStore.store(s.pattern, DCDB::PublicSensor::publicSensorToMetadata(s));
+        newMetadataStore->store(s.pattern, DCDB::PublicSensor::publicSensorToMetadata(s));
     }
 
     //Build the tree navigator
-    LOG(info) << "Building the sensor navigator...";
-    _separator = _hierarchySettings.separator;
-    _smootherRegex = boost::regex(_hierarchySettings.smootherRegex);
-    _numRegex = boost::regex("[0-9]+");
-    _navigator = new SensorNavigator();
-    _navigator->setFilter(_hierarchySettings.filter);
-    _navigator->buildTree(_hierarchySettings.regex, &topics);
+    newNavigator->setFilter(_hierarchySettings.filter);
+    newNavigator->buildTree(_hierarchySettings.regex, &topics);
+    
+    //Replacing the old navigator and metadata store
+    _navigator = newNavigator;
+    _metadataStore = newMetadataStore;
+    _updating.store(false);
+    LOG(info) << "Built a sensor navigator of size " << std::to_string(_navigator->getTreeSize()) << " and depth " << std::to_string(_navigator->getTreeDepth()) << ".";
     
     return true;
 }
@@ -219,7 +213,7 @@ void RestAPI::POST_query(endpointArgs) {
     for(auto& sensorName : sensors) {
         results.clear();
         try {
-            sm = _metadataStore.get(sensorName);
+            sm = _metadataStore->get(sensorName);
         } catch(const std::invalid_argument &e) {}
         
         uint64_t sInterval = sm.getInterval() ? *sm.getInterval() : 0;
@@ -278,3 +272,13 @@ void RestAPI::POST_query(endpointArgs) {
     res.result(http::status::ok);
     return;
 }
+
+void RestAPI::PUT_navigator(endpointArgs) {
+    if(!buildTree()) {
+        res.body() = "Sensor navigator could not be rebuilt.";
+        res.result(http::status::internal_server_error);
+    } else {
+        res.body() = "Built a sensor navigator of size " + std::to_string(_navigator->getTreeSize()) + " and depth " + std::to_string(_navigator->getTreeDepth()) + ".";
+        res.result(http::status::ok);
+    }
+}

grafana/RestAPI.h

@@ -44,6 +44,7 @@
 
 #include <boost/asio.hpp>
 #include <boost/regex.hpp>
+#include <atomic>
 
 #define MAX_DATAPOINTS 100000
 
@@ -59,10 +60,20 @@ public:
             hierarchySettings_t hierarchySettings,
             DCDB::Connection* cassandraConnection);
     
-    virtual ~RestAPI() { clear(); }
-
-    bool initTree();
-
+    virtual ~RestAPI() {
+        if(_sensorConfig) {
+            delete _sensorConfig;
+            _sensorConfig = NULL;
+        }
+        if(_sensorDataStore) {
+            delete _sensorDataStore;
+            _sensorDataStore = NULL;
+        }
+    }
+
+    //Builds the internal sensor navigator
+    bool buildTree();
+    
 private:
 
 /******************************************************************************/
@@ -124,6 +135,17 @@ private:
      */
     void POST_query(endpointArgs);
 
+    /**
+     * PUT "/navigator"
+     *
+     * @brief Reloads the sensor navigator.
+     *
+     * Queries  | key     | possible values      | explanation
+     * -------------------------------------------------------------------------
+     * Required |  -      |        -             |      -
+     */
+    void PUT_navigator(endpointArgs);
+
 /******************************************************************************/
 
     //Clears all internal storage
@@ -133,11 +155,13 @@ private:
     inline int64_t sign(int64_t val) { return val < 0 ? -1 : 1; }
     inline int64_t abs(int64_t val) { return val < 0 ? -val : val; }
 
-    SensorNavigator*    _navigator;
+    std::shared_ptr<SensorNavigator> _navigator;
+    std::shared_ptr<MetadataStore> _metadataStore;
     DCDB::Connection*   _connection;
     DCDB::SensorConfig* _sensorConfig;
     DCDB::SensorDataStore* _sensorDataStore;
-    MetadataStore _metadataStore;
+    atomic<bool> _updating;
+    
     std::string _separator;
     hierarchySettings_t _hierarchySettings;
     boost::regex _smootherRegex;