ProcFS plugin added

- Supports sampling of the vmstat, meminfo, and stat files in the proc virtual filesystem
- Basic functionality verified, extensive testing to come in the next days
- Readme and Makefile have been updated as well

Makefile

@@ -17,7 +17,7 @@ CXXFLAGS =	-std=c++11 -DBOOST_DATE_TIME_POSIX_TIME_STD_CONFIG -DBOOST_NETWORK_EN
 LIBS = -L../deps/mosquitto_build/lib -L$(DCDBDEPLOYPATH)/lib/ -ldl -lmosquitto -lboost_system -lboost_thread -lboost_log_setup -lboost_log -lpthread -lcrypto -lssl -lcppnetlib-server-parsers -lcppnetlib-uri -rdynamic
 OBJS = src/dcdbpusher.o src/Configuration.o src/MQTTPusher.o src/HttpsServer.o
 
-PLUGINS = pdu sysfs ipmi bacnet snmp
+PLUGINS = procfs pdu sysfs ipmi bacnet snmp
 ifeq ($(OS),Darwin)
 	BACNET_PORT = bsd
 	LIBEXT = dylib
@@ -92,6 +92,9 @@ libdcdbplugin_bacnet.$(LIBEXT): src/sensors/bacnet/BACnetSensorGroup.o src/senso
 	
 libdcdbplugin_snmp.$(LIBEXT): src/sensors/snmp/SNMPSensorGroup.o src/sensors/snmp/SNMPConnection.o src/sensors/snmp/SNMPConfigurator.o
 	$(CXX) $(LIBFLAGS)$@ -o $@ $^ -L$(DCDBDEPLOYPATH)/lib/ -lboost_log -lboost_system -lnetsnmp -lnetsnmpagent
+
+libdcdbplugin_procfs.$(LIBEXT): src/sensors/procfs/ProcfsSensorGroup.o src/sensors/procfs/ProcfsParser.o src/sensors/procfs/ProcfsConfigurator.o
+	$(CXX) $(LIBFLAGS)$@ -o $@ $^ -L$(DCDBDEPLOYPATH)/lib/ -lboost_log -lboost_system
 	
 #libdcdbplugin_opa.$(LIBEXT): src/sensors/opa/OpaSensorGroup.o src/sensors/opa/OpaConfigurator.o
 #	$(CXX) $(LIBFLAGS)$@ -o $@ $^ -L$(DCDBDEPLOYPATH)/lib/ -lboost_log -lboost_system -lopamgt -libverbs -libumad -lssl

README.md

@@ -19,7 +19,8 @@
     6. [BACnet](#bacnet)
     7. [OPA](#opa)
         1. [counterData](#opaCounterData)
-    8. [Writing own plugins](#writingOwnPlugins)
+    8. [ProcFS](#procfs)
+    9. [Writing own plugins](#writingOwnPlugins)
 3. [TODOS](#todos)
 
 ## Introduction <a name="introduction"></a>
@@ -467,6 +468,24 @@ Possible values for cntData:
 * linkDowned
 * uncorrectableErrors
 
+## ProcFS (/proc filesystem) <a name="procfs"></a>
+
+The ProcFS plugin enables dcdbpusher to sample resource usage metrics from a variety of files in the /proc virtual filesystem generated by the Linux kernel. Each defined sensor group is assigned to a specific file, which is periodically parsed. Currently supported files for sampling are:
+* /proc/vmstat: contains virtual memory-related usage metrics;
+* /proc/meminfo: contains RAM memory-related usage metrics (note that some of the metrics overlap with /proc/vmstat);
+* /proc/stat: contains CPU usage-related metrics, both at system and core levels.
+
+Note that in the ProcFS plugin, MQTT topics are automatically generated at runtime depending on the number of metrics found in each parsed file. For this reason, please be careful when configuring the plugin so that its MQTT topics do not overlap with those of other plugins.
+
+Explanation of the values specific for the ProcFS plugin:
+
+| Value | Explanation |
+|:----- |:----------- |
+| type | The type of the file parsed by the sensor group. Can be either "vmstat", "meminfo", or "procstat"
+| path | Path of the file, if different from the default path in the /proc filesystem
+| mqttPart | The mqttPart works similarly as in the Perf-event plugin. For sensors associated to metrics that are core-specific (i.e. some of those in /proc/stat) the mqttPart is replaced with the CPU id. For all other metrics that are system-wide, the mqttPart is used as it is.
+| mqttStart | Base MQTT suffix that is automatically incremented to generate topics for sensors associated to metrics in the same file. Note that mqttPart and mqttStart, when combined, must form a string of 4 hex characters, or 16 bits.
+
 ## Writing own plugins <a name="writingOwnPlugins"></a>
 First make sure you read the [plugins](#plugins) section.
 Try out the `pluginGenerator/generatePlugin.sh` script!

config/procfs.conf

+global {
+mqttPrefix    /FF112233445566778899AABB
+}
+
+template_file def1 {
+interval    1000
+minValues   3
+mqttPart    00
+mqttStart   E0
+}
+
+
+file vmstat {
+default     def1
+path        /Users/di52bul/dcdb/vmstat
+type        vmstat
+mqttPart    B0
+mqttStart   00
+}
+
+file meminfo {
+default     def1
+path        /Users/di52bul/dcdb/meminfo
+type        meminfo
+mqttPart    C0
+mqttStart   00
+}
+
+file procstat {
+default     def1
+path        /Users/di52bul/dcdb/stat
+type        procstat
+mqttPart    D0
+mqttStart   00
+}

src/sensors/procfs/ProcfsConfigurator.cpp

+/*
+ * ProcfsConfigurator.cpp
+ *
+ *  Created on: 18.10.2018
+ *      Author: Alessio Netti
+ */
+
+#include "ProcfsConfigurator.h"
+
+/**
+ *  Class constructor.
+ *
+ */
+ProcfsConfigurator::ProcfsConfigurator() {
+    _groupName = "file";
+    _baseName = "INVALID";
+    _entityName = "INVALID";
+}
+
+/**
+ *  Class destructor.
+ *
+ */
+ProcfsConfigurator::~ProcfsConfigurator() {}
+
+/**
+ * Increases by a certain value the input MQTT hex topic.
+ *
+ * Example: a mqtt="AAB7" and val=5 produce "AAC2" as output.
+ *
+ * @param mqtt: the MQTT hex string whose value has to be increased
+ * @param val: the value by which mqtt has to be increased
+ *
+ * @return the increased MQTT string
+ *
+ */
+const std::string ProcfsConfigurator::increaseMqtt(const std::string& mqtt, int val) {
+    unsigned long mqttDigits = stoul(mqtt, 0, 16);
+    mqttDigits += val;
+    std::stringstream stream;
+    stream << std::setfill ('0') << std::setw(mqtt.length()) << std::uppercase << std::hex << mqttDigits;
+    return stream.str();
+}
+
+/**
+ * Formats a numerical CPU core ID into a hex string of specified length.
+ *
+ * Example: a mqttPart="xx" and val=11 produce "0B" as output.
+ *
+ * @param mqttPart: a template MQTT string, defines the length of the final string
+ * @param val: the value of the CPU core ID
+ *
+ * @return the hex string representation of the input CPU core ID
+ *
+ */
+const std::string ProcfsConfigurator::formatMqttCPU(const std::string& mqttPart, unsigned int val) {
+    std::stringstream stream;
+    stream << std::setfill ('0') << std::setw(mqttPart.length()) << std::uppercase << std::hex << val;
+    return stream.str();
+}
+
+/**
+ * Reads a configuration file and instantiates Procfs Sensor Groups accordingly.
+ *
+ * Unlike in ConfiguratorTemplate, the assignment of MQTT topics to sensor is done in the
+ * sensorGroup() method.
+ *
+ * @param cfgPath: the path to the configuration file to be used
+ * @return true if successful, false otherwise
+ *
+ */
+bool ProcfsConfigurator::readConfig(std::string cfgPath) {
+    _cfgPath = cfgPath;
+    
+    boost::property_tree::iptree cfg;
+    boost::property_tree::read_info(cfgPath, cfg);
+    
+    // Read global variables (if present overwrite those from global.conf)
+    readGlobal(cfg);
+    
+    // Read groups and templates for groups. Entities and single sensors are ignored as they are not supported in this plugin
+    BOOST_FOREACH(boost::property_tree::iptree::value_type &val, cfg) {
+        // Read template group
+        if (boost::iequals(val.first, "template_" + _groupName)) {
+            LOG(debug) << "Template " << _groupName << " \"" << val.second.data() << "\"";
+            if (!val.second.empty()) {
+                ProcfsSensorGroup* group = new ProcfsSensorGroup(val.second.data());
+                if (readSensorGroup(*group, val.second)) {
+                    auto ret = _templateSensorGroups.insert(std::pair<std::string, ProcfsSensorGroup*>(val.second.data(), group));
+                    if(!ret.second) {
+                        LOG(warning) << "Template " << _groupName << " " << val.second.data() << " already exists! Omitting...";
+                    }
+                } else {
+                    LOG(warning) << "Template " << _groupName << " \"" << val.second.data() << "\" has bad values! Ignoring...";
+                }
+            }
+        // Read sensor group
+        } else if (boost::iequals(val.first, _groupName)) {
+            LOG(debug) << _groupName << " \"" << val.second.data() << "\"";
+            if (!val.second.empty()) {
+                ProcfsSensorGroup* group = new ProcfsSensorGroup(val.second.data());
+                if (readSensorGroup(*group, val.second)) {
+                    storeSensorGroup(group);
+                } else {
+                    LOG(warning) << _groupName << " \"" << val.second.data() << "\" has bad values! Ignoring...";
+                }
+            }
+        }
+    }
+    return true;
+}
+
+/**
+ * Configures a ProcfsSensorGroup object instantiated by the readSensorGroup method.
+ *
+ * For simplicity, the assignment of MQTT topics to sensors is done here and not in readConfig(),
+ * unlike in ConfiguratorTemplate.
+ *
+ * @param sGroup: the ProcfsSensorGroup object to be configured
+ * @param config: the BOOST property (sub-)tree containing configuration options for the sensor group
+ *
+ */
+void ProcfsConfigurator::sensorGroup(ProcfsSensorGroup& sGroup, CFG_VAL config) {
+    // Read additional configuration parameters supported by the Procfs plugin
+    std::string filePath="", fileType="", mqttStart="00";
+    BOOST_FOREACH(boost::property_tree::iptree::value_type &val, config) {
+        if (boost::iequals(val.first, "type")) {
+            fileType = val.second.data();
+        } else if (boost::iequals(val.first, "path")) {
+            filePath = val.second.data();
+        } else if (boost::iequals(val.first, "mqttStart")) {
+            mqttStart = val.second.data();
+        }
+    }
+    
+    ProcfsParser *parser;
+    // The "type" parameter must refer to either vmstat, procstat or meminfo. If not, the sensor group is not initialized
+    // The only other case is when an empty string is found, which can happen for template groups
+    if(fileType == "")
+        return;
+    else if(fileType == "vmstat")
+        parser = new VmstatParser(filePath);
+    else if(fileType == "procstat")
+        parser = new ProcstatParser(filePath);
+    else if(fileType == "meminfo")
+        parser = new MeminfoParser(filePath);
+    else {
+        LOG(warning) << _groupName << " " << sGroup.getGroupName() << "::" << "Unspecified or invalid type! Available types are vmstat, meminfo, procstat";
+        return; }
+    
+    // Probing the target file to be monitored and counting the available metrics
+    parser->init();
+    std::vector<std::string> *availableMetrics = parser->readNames();
+    int numMetrics = parser->getNumMetrics();
+    // If no metrics were found in the file (or the file is unreadable) the configuration aborts
+    if(numMetrics == 0) {
+        LOG(warning) << _groupName << " " << sGroup.getGroupName() << "::" << "Unable to parse file " << filePath << "!";
+        return;
+    }
+    
+    LOG(debug) << "  Number of metrics found: " << numMetrics;
+    
+    // Vector that keeps track of the current number of metrics for each CPU core for which a MQTT topic has been assigned
+    // All core-independent metrics refer to position 0 in the vector
+    std::vector<unsigned int> *metricsCounter = new std::vector<unsigned int>(parser->getNumCPUs() + 1);
+    // Reading the number of CPU cores present in the system (if needed by the sensor group)
+    std::vector<short> *metricsCores = parser->readCPUs();
+    for(int i=0;i < metricsCounter->size(); i++) metricsCounter->at(i) = 0;
+
+    // Adding the sensors corresponding to availablMetrics
+    for(int i=0;i < numMetrics; i++) {
+        ProcfsSensorBase* sensor = new ProcfsSensorBase(availableMetrics->at(i));
+        // If the metric does not refer to a specific CPU core, the topic is prefix + default mqttPart + suffix
+        // The suffix is increased automatically through the metricsCounter vector
+        if( metricsCores == NULL || ( metricsCores != NULL && metricsCores->at(i) == -1 )) {
+            sensor->setMqtt(_mqttPrefix + sGroup.getMqttPart() + this->increaseMqtt(mqttStart, metricsCounter->at(0)));
+            metricsCounter->at(0)++;
+        }
+        // If the metrics refers to a specific CPU core, the topic is prefix + CPU core ID + suffix
+        // The suffix is automatically increased for each core through the metricsCounter vector
+        else {
+            // setMqtt is used twice for readability
+            sensor->setMqtt(this->increaseMqtt(mqttStart, metricsCounter->at(metricsCores->at(i) + 1)));
+            sensor->setMqtt(_mqttPrefix + this->formatMqttCPU(sGroup.getMqttPart(), metricsCores->at(i)) + sensor->getMqtt());
+            metricsCounter->at(metricsCores->at(i) + 1)++;
+        }
+        sGroup.pushBackSensor(sensor);
+    }
+    
+    // De-allocating memory and restoring the parser to its default state
+    delete metricsCounter;
+    parser->close();
+    // Assigning the parser to the sensor group
+    sGroup.setParser(parser);
+    sGroup.setType(fileType);
+    }

src/sensors/procfs/ProcfsConfigurator.h

+/*
+ * ProcfsConfigurator.h
+ *
+ *  Created on: 17.10.2018
+ *      Author: Alessio Netti
+ */
+
+#ifndef PROCFSCONFIGURATOR_H_
+#define PROCFSCONFIGURATOR_H_
+
+#include <iostream>
+#include <sstream>
+#include <iomanip>
+#include <vector>
+#include "ProcfsSensorGroup.h"
+#include "../../includes/ConfiguratorTemplate.h"
+
+/**
+ *  Class used to configure and instantiate Procfs plugins, using config files.
+ *
+ */
+class ProcfsConfigurator : public ConfiguratorTemplate<ProcfsSensorBase, ProcfsSensorGroup> {
+    
+public:
+    // Constructor and destructor
+    ProcfsConfigurator();
+    virtual ~ProcfsConfigurator();
+
+protected:
+    // There are no sensor or sensor entities to be read from the config file, only groups
+    // Therefore, we only deal with the sensorGroup method from ConfiguratorTemplate
+    void sensorGroup(ProcfsSensorGroup& sGroup, CFG_VAL config) override;
+    void sensorBase(ProcfsSensorBase& s, CFG_VAL config) override {}
+    // The readConfig method has to be overridden as the MQTT topic logic is custom
+    bool readConfig(std::string cfgPath) override;
+    
+    // Copy-paste of the method in the perfevent plugin, used to increase MQTT topics
+    const std::string increaseMqtt(const std::string& mqtt, int val);
+    // Similar to the above, formats a numerical CPU core ID into an hex string
+    const std::string formatMqttCPU(const std::string& mqttPart, unsigned int val);
+};
+
+// Functions required to correctly generate Configurator objects from linked libraries
+
+extern "C" ConfiguratorInterface* create() {
+	return new ProcfsConfigurator;
+}
+
+extern "C" void destroy(ConfiguratorInterface* c) {
+	delete c;
+}
+
+#endif /* PROCFSCONFIGURATOR_H_ */

src/sensors/procfs/ProcfsParser.cpp

+//
+//  ProcfsParser.cpp
+//  dcdbpusher
+//
+//  Created by Netti, Alessio on 15.10.18.
+//  Copyright © 2018 LRZ. All rights reserved.
+//
+
+#include "ProcfsParser.h"
+
+// Definitions for the ProcfsParser abstract class
+
+/**
+ * Class constructor.
+ *
+ * @param path: string containing the path to the file to be parsed
+ *
+ */
+ProcfsParser::ProcfsParser(std::string path) {
+    this->_path = path;
+    this->_numMetrics = 0;
+    this->_numCPUs = 0;
+    this->_metricsNames = NULL;
+    this->_metricsReadings = NULL;
+    this->_metricsCores = NULL;
+    this->_initialized = false;
+    this->_metricsFile = NULL;
+    this->_stringBuffer = NULL;
+    this->_chars_read = 0;
+}
+
+/**
+ * Class destructor.
+ *
+ */
+ProcfsParser::~ProcfsParser() { this->close(); }
+
+/**
+ * Initializes the parser.
+ *
+ * If a file can be opened at the specified path, and metrics can be successfully parsed and read, the parser is flagged as initialized.
+ * If any of this fails, the parser remains in its un-initialized state.
+ *
+ * @return true if initialization was successful, false otherwise
+ */
+bool ProcfsParser::init() {
+    if( this->_initialized == true )
+        return true;
+    if ((this->_metricsFile = fopen(this->_path.c_str(), "r")) == NULL)
+        return false;
+    // For the parser to be initialized, the metrics' names must be successfully read, together with the corresponding initial readings
+    this->_initialized = this->_readNames() != NULL && this->_readMetrics() != NULL;
+    return this->_initialized;
+}
+
+/**
+ * Closes the parser.
+ *
+ * The open file handle is closed, all memory is released, and the parser returns to a un-initialized state.
+ *
+ */
+void ProcfsParser::close() {
+    if( !this->_initialized )
+        return;
+    if( this->_metricsFile != NULL) fclose(this->_metricsFile);
+    this->_metricsFile = NULL;
+    this->_metricsNames->clear();
+    this->_metricsReadings->clear();
+    if( this->_stringBuffer != NULL ) free(this->_stringBuffer);
+    if( this->_metricsNames != NULL ) delete this->_metricsNames;
+    if( this->_metricsReadings ) delete this->_metricsReadings;
+    if( this->_metricsCores != NULL ) delete this->_metricsCores;
+    this->_stringBuffer = NULL;
+    this->_metricsNames = NULL;
+    this->_metricsReadings = NULL;
+    this->_metricsCores = NULL;
+    this->_numMetrics = 0;
+    this->_numCPUs = 0;
+    this->_initialized = false;
+}
+
+/**
+ * Returns the vector of strings representing the name of each metric in the target file.
+ *
+ * The parser must have been initialized earlier through the init() method.
+ *
+ * @return    Pointer to a vector of strings if the parser is initialized, NULL otherwise
+ */
+std::vector<std::string> *ProcfsParser::readNames() {
+    if( !this->_initialized )
+        return NULL;
+    return this->_readNames();
+}
+
+/**
+ * Returns the vector of values for the readings of metrics in the target file.
+ *
+ * The parser must have been initialized earlier through the init() method.
+ *
+ * @return    Pointer to a vector of reading_t structures if the parser is initialized and no errors are encountered, NULL otherwise
+ */
+std::vector<reading_t> *ProcfsParser::readMetrics() {
+    if( !this->_initialized )
+        return NULL;
+    return this->_readMetrics();
+}
+
+/**
+ * Returns the vector of values representing the CPU core associated to each metric (if any).
+ *
+ * Unlike in readNames() and readMetrics(), here we return directly the vector of CPU core IDs instead of calling a private method.
+ * The reading of CPU IDs is done in _readNames(), if necessary. Where not required, NULL is returned.
+ *
+ * @return    Pointer to a vector of short integers containing the CPU core of each metric, if any, and NULL otherwise
+ */
+std::vector<short> *ProcfsParser::readCPUs() {
+    if( !this->_initialized )
+        return NULL;
+    return this->_metricsCores;
+}
+
+// **************************************************************
+// Definitions for the VmstatParser class
+
+/**
+ * Returns the vector of strings representing the name of each metric in the target vmstat (or meminfo) file.
+ *
+ * This private method does not perform any check on the status of the parser, and is meant to only contain the parsing logic.
+ * As vmstat and meminfo do not contain CPU-related information, the _metricsCores vector is left NULL.
+ *
+ * @return    Pointer to a vector of strings
+ */
+std::vector<std::string> *VmstatParser::_readNames() {
+    if ( this->_metricsNames == NULL ) {
+        this->_metricsNames = new std::vector<std::string>();
+        char *lineToken, *savePtr;
+        fseek(this->_metricsFile, 0, SEEK_SET);
+        // Reading the target file line by line
+        while( getline(&_stringBuffer, &_chars_read, this->_metricsFile) > 0 ) {
+            savePtr = NULL;
+            // strtok splits the line in delimiter-separated tokens
+            lineToken = strtok_r(this->_stringBuffer, this->LINE_SEP, &savePtr);
+            if( lineToken == NULL ) {
+                // Found a malformed line, aborting
+                this->_metricsNames->clear();
+                break;
+            }
+            this->_metricsNames->push_back(std::string(lineToken));
+        }
+        this->_numMetrics = this->_metricsNames->size();
+    }
+    return this->_metricsNames;
+}
+
+/**
+ * Returns the vector of values for the readings of metrics in the target vmstat (or meminfo) file.
+ *
+ * This private method does not perform any check on the status of the parser, and is meant to only contain the parsing logic.
+ *
+ * @return    Pointer to a vector of reading_t structures if no errors are encountered, NULL otherwise
+ */
+std::vector<reading_t> *VmstatParser::_readMetrics() {
+    if ( this->_metricsReadings == NULL )
+        this->_metricsReadings = new std::vector<reading_t>(this->_numMetrics);
+    fseek(this->_metricsFile, 0, SEEK_SET);
+    int ctr = 0;
+    char *lineToken, *savePtr;
+    // Reading the target file line by line
+    // Any changes in the file compared to when initialization was performed cause the method to return NULL
+    while( getline(&_stringBuffer, &_chars_read, this->_metricsFile) > 0 ) {
+        // Error: there are more lines/metrics than those counted with _readNames() upon initialization
+        if( ctr >= this->_numMetrics )
+            return NULL;
+        savePtr = NULL;
+        lineToken = strtok_r(this->_stringBuffer, this->LINE_SEP, &savePtr);
+        // First token is discarded, represents the metric's name
+        if(lineToken == NULL) return NULL;
+        // Second token is the actual metric
+        lineToken = strtok_r(NULL, this->LINE_SEP, &savePtr);
+        if(lineToken == NULL) return NULL;
+        try { this->_metricsReadings->at(ctr++).value = std::stoll(lineToken); }
+        catch (const std::invalid_argument& ia) { return NULL; }
+        catch (const std::out_of_range& oor) { return NULL; }
+    }
+    // Error: the number of read metrics is lower than the number of counted metrics upon initialization
+    if( ctr < this->_numMetrics ) return NULL;
+    return this->_metricsReadings;
+}
+
+// **************************************************************
+// Definitions for the ProcstatParser class
+
+/**
+ * Returns the vector of strings representing the name of each metric in the target stat file.
+ *
+ * This private method does not perform any check on the status of the parser, and is meant to only contain the parsing logic.
+ * Additionally, this method computes for each metric the associated CPU core (if any), which can be inferred from the metric name iself.
+ *
+ * @return    Pointer to a vector of strings
+ */
+std::vector<std::string> *ProcstatParser::_readNames() {
+    if ( this->_metricsNames == NULL ) {
+        this->_metricsNames = new std::vector<std::string>();
+        this->_metricsCores = new std::vector<short>();
+        char *lineToken, *savePtr;
+        short currCPU = -1;
+        
+        fseek(this->_metricsFile, 0, SEEK_SET);
+        // Reading the target file line by line
+        while( getline(&_stringBuffer, &_chars_read, this->_metricsFile) > 0 ) {
+            savePtr = NULL;
+            // First token in the line is the metric's name
+            lineToken = strtok_r(this->_stringBuffer, this->LINE_SEP, &savePtr);
+            if( lineToken == NULL ) {
+                // Found a malformed line, aborting
+                this->_metricsNames->clear();
+                this->_metricsCores->clear();
+                this->_numCPUs = 0;
+                break;
+            }
+            // We check whether the line is cpu core-related or not through a regular expression
+            // If the name contains the "cpu" keyword, then it is cpu-related
+            if( std::regex_search(lineToken, this->_match, this->reg_exp) ) {
+                // If a match to an integer number is found within the name, the metric is related to a specific core. Otherwise,
+                // it is considered as a system-wide metric
+                try { currCPU = !std::regex_search(lineToken, this->_match, reg_exp_num) ? -1 : (short)std::stol(this->_match.str(0)); }
+                catch (const std::invalid_argument& ia) { return NULL; }
+                catch (const std::out_of_range& oor) { return NULL; }
+                // The number of CPU cores in the system is inferred from the maximum CPU ID found while parsing
+                if( currCPU >= this->_numCPUs ) this->_numCPUs = currCPU + 1;
+                std::string cpuName(lineToken);
+                this->_actualMetrics = 0;
+                while( (lineToken = strtok_r(this->_stringBuffer, this->LINE_SEP, &savePtr)) != NULL && this->_actualMetrics < this->DEFAULTMETRICS ) {
+                    this->_metricsNames->push_back(cpuName + "_" + this->DEFAULT_NAMES[this->_actualMetrics]);
+                    this->_metricsCores->push_back(currCPU);
+                    // This variable counts the number of metrics for each CPU that are effectively parsed from the stat file
+                    // Current maximum allowed is 10 metrics, any additional metrics are discarded
+                    this->_actualMetrics++;
+                }
+            }
+            // If the metric is not cpu core-related, it is simply pushed to the _metricsNames vector
+            else {
+                currCPU = -1;
+                this->_metricsNames->push_back(std::string(lineToken));
+                this->_metricsCores->push_back(currCPU);
+            }
+        }
+        this->_numMetrics = this->_metricsNames->size();
+    }
+    return this->_metricsNames;
+}
+
+/**
+ * Returns the vector of values for the readings of metrics in the target stat file.
+ *
+ * This private method does not perform any check on the status of the parser, and is meant to only contain the parsing logic.
+ *
+ * @return    Pointer to a vector of reading_t structures if no errors are encountered, NULL otherwise
+ */
+std::vector<reading_t> *ProcstatParser::_readMetrics() {
+    if ( this->_metricsReadings == NULL )
+        this->_metricsReadings = new std::vector<reading_t>(this->_numMetrics);
+    fseek(this->_metricsFile, 0, SEEK_SET);