Do not use MonLogger in StdOut backend (#85)

Author: awegrzyn

src/Backends/StdOut.cxx

@@ -4,9 +4,8 @@
 ///
 
 #include "StdOut.h"
-
-#include <iostream>
 #include "../MonLogger.h"
+#include <iostream>
 
 namespace o2
 {
@@ -24,7 +23,7 @@ inline unsigned long StdOut::convertTimestamp(const std::chrono::time_point<std:
   ).count();
 }
 
-StdOut::StdOut()
+StdOut::StdOut() : mStream(std::cout)
 {
   setVerbosisty(backend::Verbosity::Debug);
   MonLogger::Get() << "StdOut backend initialized" << MonLogger::End();
@@ -57,9 +56,11 @@ void StdOut::sendMultiple(std::string measurement, std::vector<Metric>&& metrics
     if (!metricTags.empty()) {
       metricTags = "," + metricTags;
     }
-    MonLogger::Get() << "[METRIC] " << measurement << "/" << metric.getName() << "," << metric.getType() << " "
-      << metric.getValue() << " " << convertTimestamp(metric.getTimestamp()) << " " << tagString << metricTags
-      << MonLogger::End();
+    auto tStamp = std::chrono::system_clock::to_time_t(metric.getTimestamp());
+    mStream << std::put_time(std::localtime(&tStamp), "%Y-%m-%d %X") << "\t"
+      <<  "[METRIC] " << measurement << "/" << metric.getName() << "," << metric.getType() << " "
+      << metric.getValue() << " " << convertTimestamp(metric.getTimestamp()) << " " << tagString
+      << metricTags << "\n";
   }
 }
 
@@ -75,9 +76,11 @@ void StdOut::send(const Metric& metric)
   if (!metricTags.empty()) {
     metricTags = "," + metricTags;
   }
-  MonLogger::Get() << "[METRIC] " << metric.getName() << "," << metric.getType() << " " << metric.getValue()
+  auto tStamp = std::chrono::system_clock::to_time_t(metric.getTimestamp());
+  mStream << std::put_time(std::localtime(&tStamp), "%Y-%m-%d %X") << "\t"
+     << "[METRIC] " << metric.getName() << "," << metric.getType() << " " << metric.getValue()
     << " " << convertTimestamp(metric.getTimestamp()) << " " << tagString << metricTags
-    << MonLogger::End();
+    << "\n";
 }
 
 } // namespace backends

src/Backends/StdOut.h

@@ -49,6 +49,9 @@ class StdOut final : public Backend
     void addGlobalTag(std::string name, std::string value) override;
 
   private:
+    /// Metric stream
+    std::ostream &mStream;
+
     /// Converts timestamp to unsigned long (miliseconds from epoch)
     /// \param timestamp    timestamp in std::chrono::time_point format
     /// \return             timestamp as unsigned long (miliseconds from epoch)