Logging is done using the Ros Singleton.


To log a message you can use one of the following methods debug, info, warn, error and fatal.

Button {
  // ...
  onClicked: Ros.info("Button clicked.")

This will produce the following output:

:: code-block:: bash

[ INFO] [1583062360.048922959]: Button clicked.

and publish the following on /rosout (unless NoRosout was specified in the RosInitOptions).

:: code-block:: bash


seq: 1 stamp:

secs: 1583062360 nsecs: 49001300

frame_id: ‘’

level: 2 name: “/qml_logging_demo” msg: “Button clicked.” file: “/home/stefan/qml_ros_plugin/examples/logging.qml” function: “onClicked” line: 130 topics: [/rosout]

The file, function and line info is automatically extracted when you call the log function.

Set Verbosity

You can change the verbosity, i.e., the minimal level of logging message that is printed (and published if enabled), using Ros.console.setLoggerLevel. By default the logging level is set to Info. To enable debug messages you can set it to Debug as follows:

Ros.console.setLoggerLevel(Ros.console.defaultName, RosConsoleLevels.Debug);

The first argument to that method is the name of the console to which the logging is printed. These are identifiers used by ros to enable you to change the verbosity of a submodule of your node using rqt_console.

You can optionally change to which console you’re writing by passing a second argument to the logging function, e.g., debug("Some message", "ros.my_pkg.my_submodule").
This name should contain only letters, numbers, dots and underscores.
Important: The name has to start with “ros.”.

By default the value of Ros.console.defaultName is used which evaluates to ros.qml_ros_plugin.

Possible values for the console level are: Debug, Info, Warn, Error and Fatal.