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Quick start

This guide covers the minimum flow: create the logger, register sinks, and emit an event.

1. Create the logger​

final logger = StructureLogger();

2. Register sinks​

Sinks define where logs go. For local development, combine readable terminal output with the Dart developer log:

logger.addSink(SimpleLineSink());
logger.addSink(DefaultSink());

3. Emit a log​

await logger.log(
  'Welcome {name}, your level is {level}',
  level: LogLevel.info,
  data: {'name': 'John Doe', 'level': 12},
);

What happens​

  1. StructureLogger builds a LogModel with an ISO-8601 timestamp, template, level, and data.
  2. Each registered sink receives the same event via write(LogModel).
  3. SimpleLineSink interpolates placeholders and prints a readable line.
  4. DefaultSink serializes the CLEF map and sends it to dart:developer.

Expected output​

Welcome John Doe, your level is 12
[log] {@t: 2026-06-25T10:00:00.000, @mt: Welcome {name}, your level is {level}, @l: info, data: {name: John Doe, level: 12}}

Full example​

import 'package:flutter/widgets.dart';
import 'package:structured_logger/structured_logger.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();

  final logger = StructureLogger();
  logger.addSink(SimpleLineSink());
  logger.addSink(DefaultSink());

  await logger.log(
    'Welcome {name}, your level is {level}',
    level: LogLevel.info,
    data: {'name': 'John Doe', 'level': 12},
  );
}

Next step​