logging 0.11.3+1

Initializing

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.

Logging messages

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.

0.11.3+1

  • Fixed several documentation comments.

0.11.3

  • Added optional LogRecord.object field.

  • Logger.log sets LogRecord.object if the message is not a string or a function that returns a string. So that a handler can access the original object instead of just its toString().

0.11.2

  • Added Logger.detached - a convenience factory to obtain a logger that is not attached to this library's logger hierarchy.

0.11.1+1

  • Include default error with the auto-generated stack traces.

0.11.1

  • Add support for automatically logging the stack trace on error messages. Note this can be expensive, so it is off by default.

0.11.0

  • Revert change in 0.10.0. stackTrace must be an instance of StackTrace. Use the Trace class from the stack_trace package to convert strings.

0.10.0

  • Change type of stackTrace from StackTrace to Object.

0.9.3

  • Added optional LogRecord.zone field.

  • Record current zone (or user specified zone) when creating new LogRecords.

1. Depend on it

Add this to your package's pubspec.yaml file:

dependencies:
  logging: "^0.11.3+1"

2. Install it

You can install packages from the command line:

$ pub get

Alternatively, your editor might support 'pub get'. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:

import 'package:logging/logging.dart';

About

Provides APIs for debugging and error logging. This library introduces abstractions similar to those used in other languages, such as the Closure JS Logger and java.util.logging.Logger.

Author

Email misc@dartlang.org Dart Team

Homepage

github.com/dart-lang/logging

Documentation

www.dartdocs.org/documentation/logging/0.11.3%2B1/

Source code (hyperlinked)

www.crossdart.info/p/logging/0.11.3%2B1/

Uploader

dgrove@google.com
jmesserly@google.com
sigmund@google.com
kevmoo@google.com
jakemac@google.com
kustermann@google.com

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