Logging Framework - v1.0

Short usage guide to the logging framework (v1.0) by Moritz Höwer

Usage

To use logging framework, include logging/logging.h. To print a log message use the provided macros LOG_XXX like you would use std::cout (XXX is ERROR, WARNING, DEBUG or TRACE).

Set logfile

To set or change the logfile use the macro SET_LOGFILE() and pass it the filename.

Set default LogLevel

To set the default LogLevel for console output (std:cout) use macro SET_LOGLEVEL_COUT() and pass it a LogLevel (ERROR, WARNING, DEBUG, TRACE, OFF).
To set the default LogLevel for logfile use macro SET_LOGLEVEL_FILE().

std::cout / the logfile will contain all log messages with a LogLevel that is at least as severe as the one specified. LogLevel::ERROR will only print ERROR, LogLevel::WARNING will print WARNING and ERROR and so on.

Configuration

For the formatted output of file paths the relative path to Logger.cpp must be known. This can be configured in logging/config.h.

The following configurations can also be made in logging/config.h:

• default loglevel for console output and logfile
• first line of logfiles
• if the build date will be included in the logfile
• use of colors

Modules

With proper use of modules, we can say more specifically which log messages we want to see.

Set Module

For adding a file (or to be more precise for a compilation unit) to a module, #define LOG_MODULE <name> before you #include "logging/logging.h. This will put all following log messages into the module. If no module is specified, log messages are put into the global module.

Select which modules to display

Using LOGGING_SET_WHITELIST(...) or LOGGING_SET_BLACKLIST(...), you can whitelist/blacklist specific (comma seperated) modules.

Specify custom LogLevels for a module

Using SET_LOGLEVELS_MODULE(<module>, <LogLevel cout>, <LogLevel file> you can set specific LogLevels for a module.

Example

#include "util/logging/logging.h"

int main() {
	SET_LOGFILE("output.log");

	SET_LOGLEVEL_COUT(LogLevel::TRACE);
	SET_LOGLEVEL_FILE(LogLevel::WARNING);
	
	LOG_SCOPE
	
	LOG_ERROR << "Test error " << 2 << std::endl;
	LOG_WARNING << "Test warning " << 3.5 << std::endl;
	LOG_DEBUG << "Test debug " << to_string(false) << std::endl;
	LOG_TRACE << "Test trace" << std::endl;
}

will print something like

[2017-10-15 16:04:29][ TRACE ][GLOBAL][main.cpp:9 (main)]: Entering Scope (0)
[2017-10-15 16:04:29][ ERROR ][GLOBAL][main.cpp:11 (main)]: Test error 2
[2017-10-15 16:04:29][WARNING][GLOBAL][main.cpp:12 (main)]: Test warning 3.5
[2017-10-15 16:04:29][ DEBUG ][GLOBAL][main.cpp:13 (main)]: Test debug false
[2017-10-15 16:04:29][ TRACE ][GLOBAL][main.cpp:14 (main)]: Test trace
[2017-10-15 16:04:29][ TRACE ][GLOBAL][main.cpp:9 (main)]: Leaving Scope (0)

and output.log will contain something like

[2017-10-15 16:04:29][ ERROR ][GLOBAL][main.cpp:11 (main)]: Test error 2
[2017-10-15 16:04:29][WARNING][GLOBAL][main.cpp:12 (main)]: Test warning 3.5