commit | 49b983da4aa538a076f55b1844a2e525166eec51 | [log] [tgz] |
---|---|---|
author | Jason Aguilon <jason.aguilon+github@workiva.com> | Mon Apr 18 11:00:23 2016 -0600 |
committer | sigmundch <sigmund@google.com> | Mon Apr 18 10:00:23 2016 -0700 |
tree | 852d1b557828dc09566f58a27d2fa792a60839c0 | |
parent | 9920fb665f28f3d69f5e556d70cc87254f9711fb [diff] |
save non-string object on LogRecord (#28) Save non-string object on `LogRecord` so that a handler can access the original object instead of just its `toString()`
By default, the logging package does not do anything useful with the log messages. You must configure the logging level and add a handler for the log messages.
Here is a simple logging configuration that logs all messages via print
.
Logger.root.level = Level.ALL; Logger.root.onRecord.listen((LogRecord rec) { print('${rec.level.name}: ${rec.time}: ${rec.message}'); });
First, set the root [Level]. All messages at or above the level are sent to the [onRecord] stream.
Then, listen on the [onRecord] stream for [LogRecord] events. The [LogRecord] class has various properties for the message, error, logger name, and more.
Create a [Logger] with a unique name to easily identify the source of the log messages.
final Logger log = new Logger('MyClassName');
Here is an example of logging a debug message and an error:
var future = doSomethingAsync().then((result) { log.fine('Got the result: $result'); processResult(result); }).catchError((e, stackTrace) => log.severe('Oh noes!', e, stackTrace));
When logging more complex messages, you can pass a closure instead that will be evaluated only if the message is actually logged:
log.fine(() => [1, 2, 3, 4, 5].map((e) => e * 4).join("-"));
See the [Logger] class for the different logging methods.