commit | a8c206f246584e5601495f9cbed1a549f38b94b5 | [log] [tgz] |
---|---|---|
author | Nate Bosch <nbosch@google.com> | Thu Sep 20 09:17:54 2018 -0700 |
committer | Nate Bosch <nbosch@google.com> | Thu Sep 20 09:17:54 2018 -0700 |
tree | f131582292d04961f312335adffb7f7a3016ff8b | |
parent | 79978e5a668b4809d6cb1d34449d9425b7258ecd [diff] |
Update to best practices in README - Omit `new`. - Avoid an inferrable type on the listener function literal. - Avoid reduntant type when intializing logger. - Don't abbreviate "record". - Reflow to 80 characters. - Change the `[]` which were not links to backticks.
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((record) { print('${record.level.name}: ${record.time}: ${record.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 log = 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.