Add option to enable json logging

CMakeLists.txt

@@ -27,6 +27,7 @@ if(WIN32 AND MSVC_VERSION LESS 1800)
   message(FATAL_ERROR "Building with Microsoft compiler needs Visual Studio 2013 or later (Express version works too)")
 endif()
 
+option(ENABLE_JSON_LOGGING "Adds additional JSON debug logging to the response" OFF)
 option(WITH_TOOLS "Build OSRM tools" OFF)
 option(BUILD_TOOLS "Build OSRM tools" OFF)
 
@@ -298,6 +299,11 @@ include_directories(${ZLIB_INCLUDE_DIRS})
 target_link_libraries(osrm-extract ${ZLIB_LIBRARY})
 target_link_libraries(osrm-routed ${ZLIB_LIBRARY})
 
+if (ENABLE_JSON_LOGGING)
+  message(STATUS "Enabling json logging")
+  add_definitions(-DENABLE_JSON_LOGGING)
+endif()
+
 if(WITH_TOOLS OR BUILD_TOOLS)
   message(STATUS "Activating OSRM internal tools")
   find_package(GDAL)

util/json_logger.hpp

@@ -48,11 +48,20 @@ class Logger
     {
         static Logger logger;
 
+        bool return_logger = true;
 #ifdef NDEBUG
-        return nullptr;
-#else
-        return &logger;
+        return_logger = false;
 #endif
+#ifdef ENABLE_JSON_LOGGING
+        return_logger = true;
+#endif
+
+        if (return_logger)
+        {
+            return &logger;
+        }
+
+        return nullptr;
     }
 
     void initialize(const std::string& name)