darto_logger

Structured logging for the Darto web framework — JSON or pretty output, levels, bound fields, and a request-logging middleware with request-id correlation.

Install

dependencies:
  darto_logger: ^1.0.0

Usage

import 'package:darto/darto.dart';
import 'package:darto/request_id.dart';
import 'package:darto_logger/darto_logger.dart';

final log = Logger(minLevel: LogLevel.debug);

void main() {
  final app = Darto();

  app.use(requestId());        // adds X-Request-Id
  app.use(requestLogger(log)); // logs each request with that id

  app.get('/', [], (c) => c.ok({'ok': true}));
  app.listen(3000, () => log.info('listening', {'port': 3000}));
}

Each request logs one structured line:

{"ts":"2026-05-27T12:00:00.000Z","level":"info","msg":"request","requestId":"…","method":"GET","path":"/","status":200,"durationMs":2}

Logger

final log = Logger(minLevel: LogLevel.info, pretty: false);

log.debug('cache miss', {'key': k});
log.info('user created', {'id': id});
log.warn('slow query', {'ms': 820});
log.error('db failed', error: e, stackTrace: s);

// Bind fields onto every subsequent line
final reqLog = log.child({'requestId': id});
reqLog.info('handled', {'status': 200});

Member	Description
`Logger({minLevel, pretty, output})`	Create a logger. `pretty` → human line; `output` → custom sink (defaults to stdout)
`debug / info / warn / error(msg, [fields])`	Log at a level; `error` also takes `error` / `stackTrace`
`child(fields)`	A logger that binds `fields` to every line
`LogLevel`	`debug` · `info` · `warn` · `error`

requestLogger(logger)

Middleware that logs method, path, status and durationMs per request. When requestId() ran before it, the id is bound to the line.

Support 💖

If you find Darto Logger useful, please consider supporting its development 🌟Buy Me a Coffee.🌟 Your support helps us improve the package and make it even better!