How to see the output of Logger in dartlang (Dartium or command-line)

Question

I'd like to be able to log for debugging purpose from a package that could be either part of a web app or a command line application

Current I use

print('some text');

But I cannot control at runtime what is printed (DEBUG, INFO, ...) While I'm used to use java.util.logging.Logger in java, I could not find a way to use the Logger class in the logging package of dart, in either a web or command line application.

Logger logger = new Logger('test');
logger.info('some text');

The simple code above compiles fine but I cannot see any ouput in either the console of Dartium or the Output pane in the DartEditor.

Has anyone successfully used it (and see some text)?

Answer 1

In my Dart Bat-belt, I keep a function like this:

void printLogRecord(LogRecord r) {
  print("${r.loggerName} ${r.level} ${r.message}");
}

Then I'll add it to a Logger, typically the root logger:

Logger.root.level = Level.FINE;
Logger.root.onRecord.listen(printLogRecord);