Make MonLogger independet from InfoLogger

Author: awegrzyn

src/Backends/InfoLoggerBackend.cxx

@@ -28,7 +28,7 @@ inline unsigned long InfoLoggerBackend::convertTimestamp(const std::chrono::time
 
 InfoLoggerBackend::InfoLoggerBackend()
 {
-  MonLogger::Get() << "InfoLogger backend initialized" << InfoLogger::endm;
+  MonLogger::Get() << "InfoLogger backend initialized" << MonLogger::End();
 }
 
 void InfoLoggerBackend::addGlobalTag(std::string name, std::string value)

src/Exceptions/MonitoringInternalException.cxx

@@ -18,7 +18,7 @@ MonitoringInternalException::MonitoringInternalException(const std::string& sour
 MonitoringInternalException::MonitoringInternalException(int code, const std::string& source, const std::string& message)
 : message(message)
 {
-  MonLogger::Get() << "MonitoringInternalException["
+  MonLogger::Get(Severity::Warn) << "MonitoringInternalException["
                        << source << "] (" << code << "): " << message << MonLogger::End();
 }
 

src/MonLogger.h

@@ -6,6 +6,8 @@
 #ifndef MONITORING_MONINFOLOGGER_H
 #define MONITORING_MONINFOLOGGER_H
 
+#include <chrono>
+#include <iomanip>
 #include <iostream>
 
 namespace AliceO2
@@ -14,40 +16,66 @@ namespace AliceO2
 namespace Monitoring
 {
 
+/// List of possible log severities
+enum class Severity { Error = 31, Warn = 33, Info = 49 };
+
 /// Simple Monitoring logging class
 class MonLogger
 {
   public:
+    /// Appends value/message to the log
+    /// \param log - message
+    /// \return - this to allow chaining
     template <typename T>
     MonLogger &operator<<(const T &log) {
-        mStream << log;
-        return *this;
+      mStream << log;
+      return *this;
     }
 
-    MonLogger &operator<<(std::ostream& (*log) (std::ostream&)) {
-        mStream << log;
-        return *this;
-    }
-    static MonLogger &Get()
+    /// Singleton
+    /// Returns Logger instance with current date and given severity
+    /// \param severity - severity level
+    /// \return - logger instance
+    static MonLogger &Get(Severity severity = Severity::Info)
     {
       static MonLogger loggerInstance;
+      loggerInstance.setDate();
+      loggerInstance.setSeverity(severity);
       return loggerInstance;
     }
-    static auto End() -> decltype("\n")
+
+    /// Terminates log line
+    /// return - string with color termination and new line
+    static auto End() -> decltype("\033[0m\n")
     {
-      return "\n";
+      return "\033[0m\n";
     }
 
   private:
+    /// Log stream
     std::ostream &mStream;
-    MonLogger(std::ostream &oStream = std::cout): mStream(oStream) {};
+
+    /// Sets cout as a log stream
+    MonLogger(std::ostream &oStream = std::cout) : mStream(oStream)
+    {}
+
+    /// Appends current datetime to log stream
+    void setDate() {
+       auto now = std::chrono::system_clock::to_time_t(std::chrono::system_clock::now());
+       mStream << std::put_time(std::localtime(&now), "%Y-%m-%d %X") << "\t";
+    }
 
+    /// Sets log color based on severity
+    /// \param severity - log severity
+    void setSeverity(Severity severity) {
+      mStream << "\033[1;" << static_cast<int>(severity) << "m";
+    }
+ 
     /// Delete copy and move constructors
     MonLogger &operator=(const MonLogger &) = delete;
     MonLogger(const MonLogger &) = delete;
     MonLogger(MonLogger &&) = delete;
     MonLogger &operator=(MonLogger&&) = delete;
-
 };
 
 } // Monitoring