Adding the Log tool

CMakeLists.txt

@@ -10,7 +10,7 @@ if( DEFINED PROJECT_NAME )
 endif()
 
 project( tools
-  VERSION 0.1.0
+  VERSION 0.2.0
   LANGUAGES CXX
 )
 

cmake/unit_testing.cmake

@@ -25,3 +25,5 @@ endfunction()
 #######################################################################
 # Unit testing directories
 #######################################################################
+
+add_subdirectory( src/tools/Log/test )

src/tools/Log.hpp

@@ -0,0 +1,132 @@
+#ifndef NJOY_TOOLS_LOG
+#define NJOY_TOOLS_LOG
+
+// system includes
+
+// other includes
+#include "spdlog/spdlog.h"
+#include "spdlog/sinks/stdout_color_sinks.h"
+#include "spdlog/sinks/basic_file_sink.h"
+
+namespace njoy {
+namespace tools {
+
+/**
+ *  @brief A singleton logger for njoy components
+ */
+class Log {
+
+  static auto initialize_logger() {
+
+    auto instance = spdlog::stdout_color_st( "njoy" );
+    instance->set_pattern( "[%^%l%$] %v" );
+    #ifndef NDEBUG
+    instance->set_level( spdlog::level::debug );
+    #endif
+    return instance;
+  }
+
+  static auto& logger() {
+
+    static auto instance = initialize_logger();
+    return instance;
+  }
+
+  /* constructors */
+  Log() {}; // private to avoid creation of Log instances
+
+public:
+
+  Log( const Log& ) = delete;
+  void operator=( const Log& ) = delete;
+
+  /**
+   *  @brief Direct the logger output to the given file
+   */
+  static void add_sink( const std::string& filename ) {
+
+    auto sink_ptr = std::make_shared< spdlog::sinks::basic_file_sink_st >( filename );
+    sink_ptr->set_pattern( "[%^%l%$] %v" );
+    logger()->sinks().push_back( sink_ptr );
+  }
+
+  /**
+   *  @brief Flush the logger
+   */
+  static void flush() {
+
+    logger()->flush();
+  }
+
+  /**
+   *  @brief Print a message at the info level
+   *
+   *  For example:
+   *
+   *  int value = 10;
+   *  utility::Log::info( "Some message with a value {}", value );
+   */
+  template< typename... Args >
+  static void info( Args... args ) {
+
+    logger()->info( std::forward< Args >( args )... );
+  }
+
+  /**
+   *  @brief Print a message at the warning level
+   *
+   *  For example:
+   *
+   *  int value = 10;
+   *  utility::Log::warning( "Some message with a value {}", value );
+   */
+  template< typename... Args >
+  static void warning( Args... args ) {
+
+    logger()->warn( std::forward< Args >( args )... );
+  }
+
+  /**
+   *  @brief Print a message at the error level
+   *
+   *  For example:
+   *
+   *  int value = 10;
+   *  utility::Log::info( "Some message with a value {}", value );
+   */
+  template< typename... Args >
+  static void error( Args... args ) {
+
+    logger()->error( std::forward< Args >( args )... );
+  }
+
+  /**
+   *  @brief Print a message at the debug level
+   *
+   *  This only prints when NDEBUG is defined when compiling this code.
+   *
+   *  For example:
+   *
+   *  int value = 10;
+   *  utility::Log::debug( "Some message with a value {}", value );
+   */
+  #ifdef NDEBUG
+    template< typename... Args >
+    static void debug( Args... ) {}
+  #else
+    template< typename... Args >
+    static void debug( Args... args ) {
+
+      logger()->debug( std::forward< Args >( args )... );
+    }
+  #endif
+};
+
+} // tools namespace
+
+/* type alias - for backwards compatibility reasons */
+using Log = tools::Log;
+
+} // njoy namespace
+
+#endif

src/tools/Log/test/CMakeLists.txt

@@ -0,0 +1 @@
+add_cpp_test( Log Log.test.cpp )

src/tools/Log/test/Log.test.cpp

@@ -0,0 +1,57 @@
+// include Catch2
+#include <catch2/catch_test_macros.hpp>
+
+// what we are testing
+#include "tools/Log.hpp"
+
+// other includes
+#include <fstream>
+#include <sstream>
+#include <filesystem>
+
+// convenience typedefs
+using namespace njoy::tools;
+
+std::string getContent( std::string filename ) {
+
+  std::stringstream ss;
+  std::ifstream fs( filename, std::ifstream::in );
+  ss << fs.rdbuf();
+  return ss.str();
+}
+
+SCENARIO( "Log" ) {
+
+  GIVEN( "a file name" ) {
+
+    std::string filename = "output.txt";
+    std::filesystem::remove( filename ); // ensure the file is not there
+
+    WHEN( "the Log redirects to a file" ) {
+
+      Log::add_sink( filename );
+
+      THEN( "the file contains the log after flushing" ) {
+
+        Log::error( "Some error occurred" );
+        Log::warning( "Some warning was issued" );
+        Log::info( "Some info was printed" );
+        Log::debug( "Some debug info was given" );
+        Log::flush();
+
+        std::string content = getContent( filename );
+
+#ifdef NDEBUG
+        CHECK( "[error] Some error occurred\n"
+               "[warning] Some warning was issued\n"
+               "[info] Some info was printed\n" == content );
+#else
+        CHECK( "[error] Some error occurred\n"
+               "[warning] Some warning was issued\n"
+               "[info] Some info was printed\n"
+               "[debug] Some debug info was given\n"   == content );
+#endif
+      } // THEN
+    } // WHEN
+  } // GIVEN
+} // SCENARIO