MOTIS utl module documentation

MOTIS is an open-source software platform for efficient planning and routing in multi-modal transportation systems. GitHub main repository: https://github.com/motis-project/motis

This is the documentation for the utl (utility) module.

Logging

The simplest way to produce log lines is to use the utl:log() function, or the wrapping functions for the various log levels, utl::log_debug(), utl::log_info() and utl::log_error():

#include "utl/logging.h"

utl::log_info("MyCtx", "Simple message");

The first parameter is the context, that provides an information of the origin of the log line inside MOTIS code.

The following log levels are supported:

debug: Messages that contain information only useful when debugging MOTIS
info: Important information about a normal behavior of the program
error: Details on an abnormal behavior of the application

Advanced usage

You can insert variables in the message by using {} and passing them as extra arguments (formatting is performed by the fmt library):

utl::log_info("MyCtx", "String={} Int={}", "Hello", 42);

You can specify metadata using .attrs():

utl::log_info("MyCtx", "Message").attrs({{"key1", "value1"}, {"key2", "value2"}});

API details

template<log_level LogLevel, typename ...Args> struct log

Produce a new log line at the given level.

Public Functions

inline void attrs(std::initializer_list<std::pair<std::string_view, std::string_view>> &&attrs): Add key-values metadata.

template<typename ...Args> struct log_debug : public utl::log<log_level::debug, Args...>: Produce a new DEBUG log line.

template<typename ...Args> struct log_info : public utl::log<log_level::info, Args...>: Produce a new INFO log line.

template<typename ...Args> struct log_error : public utl::log<log_level::error, Args...>: Produce a new ERROR log line.

Note

Those logging function are an exception to the rule that, in MOTIS, we use Aggregate Initialization wherever possible, but here we do not want to use utl::log_info{...}.