Simple Logger

This package allows to see how it is possible to use the ROS2 C++ logger API and its features.

Usage

You can run the example with:

ros2 run simple_logger logger_main

The example will create a node, which is automatically associated to a logger with the same name.

The logger is used to log messages with different levels. The default verbosity level is INFO for all loggers.

It is possible to change the verbosity level of each logger at runtime.

Moreover, we show how to create a logger that is not connected to any node.

rosout Topic

A new feature introduced in January 2019, is the possibility of publishing all the logs to a rosout topic. You can try it by buildin the master branch of ROS2 or any distribution successive to Crystal.

The interface for Log messages is defined here.

In order to see all the published log messages, you can open a new terminal and run

ros2 topic echo /rosout

This feature is automatically enabled. You can disable it through a command line argument

ros2 run simple_logger logger_main __log_disable_rosout:=true

NOTE: This feature will only work for loggers associated with a node. According to the ROS documentation:

Because of the way ROS 2 associates DDS concepts with ROS Nodes, there didn’t seem to be a clean way to setup a general topic on a process that wasn’t associated with an existing Node. Since a process can also contain multiple ROS Nodes, we didn’t think it would be good design to just pick one to have everything published to.