Console logging

During development, combining SimpleLineSink and DefaultSink covers most cases.

Recommended setup

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

final logger = StructureLogger();

void setupLogging() {
  if (kDebugMode) {
    logger.addSink(SimpleLineSink());
    logger.addSink(DefaultSink());
  }
}

• SimpleLineSink — quick reading in the terminal (flutter run).
• DefaultSink — inspection in Flutter DevTools and the IDE log panel.

Log levels

Use LogLevel to classify events:

await logger.log('App started', level: LogLevel.info);
await logger.log('Cache miss for {key}', level: LogLevel.debug, data: {'key': 'user_prefs'});
await logger.log('Retry {attempt} of {max}', level: LogLevel.warning, data: {'attempt': 2, 'max': 5});
await logger.log('Request failed: {error}', level: LogLevel.error, data: {'error': 'timeout'});
await logger.log('Frame {n} rendered', level: LogLevel.verbose, data: {'n': 1204});

Level	Typical use
verbose	Fine-grained trace, high volume
debug	Development diagnostics
info	Normal application flow
warning	Recoverable or unexpected situation
error	Failure that deserves attention

Tips

• Register sinks once at app startup (e.g. in main() after WidgetsFlutterBinding.ensureInitialized()).
• In release builds, consider removing SimpleLineSink to avoid print in production.
• For production, prefer SinkSeq or a custom sink that sends to your observability backend.