Logging

Logging is done using the Ros2 Singleton.

Output

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

Button {
  // ...
  onClicked: Ros2.info("Button clicked.")
  // or using a named logger
  onClicked: Ros2.getLogger("my_logger").info("Button clicked.")
}

This will produce the following output:

[ INFO] [1583062360.048922959] [qml_logging_demo]: Button clicked.

and publish the following on /rosout (unless NoRos2out was specified in the Ros2InitOptions).

header:
  seq: 1
  stamp:
    secs: 1583062360
    nsecs:  49001300
  frame_id: ''
level: 2
name: "/qml_logging_demo"
msg: "Button clicked."
file: "/home/stefan/qml_ros2_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 Ros2.getLogger().setLoggerLevel. You can also use Ros2.getLogger() to obtain a named logger instance. By default the logging level is set to Info. To enable debug messages you can set it to Debug as follows:

Ros2.getLogger().setLoggerLevel(Ros2LoggerLevel.Debug);
// or
Ros2.getLogger("my_logger").setLoggerLevel(Ros2LoggerLevel.Warn)

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 create named loggers using the Ros2.getLogger(QString) method.

This name should contain only letters, numbers, dots and underscores.

By default the logger name is the node name passed to Ros2.init().

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