otel_logger

OpenTelemetry instrumentation for package:logger — the popular pretty-print logger by leisim.

import 'package:logger/logger.dart';
import 'package:otel_logger/otel_logger.dart';

final logger = Logger(
  output: MultiOutput([
    ConsoleOutput(),   // keep the pretty terminal output
    OTelLogOutput(),   // mirror every event into OTel logs
  ]),
);

logger.i('user signed in');
// → terminal: prettified line
// → OTel logs: structured record with severity_number=INFO,
//   body="user signed in", trace_id/span_id from the active span

Each OutputEvent becomes one OTel log record:

• body — joined output lines (prettified prefixes preserved)
• severity_number — logger.Level → OTel Severity: trace→TRACE, debug→DEBUG, info→INFO, warning→WARN, error→ERROR, fatal→FATAL
• severity_text — event.level.name
• timestamp — from event.origin.time
• exception.type / .message / .stacktrace — when LogEvent.error / .stackTrace are non-null

Span correlation

Log calls inside a Tracer.startActiveSpan block automatically carry the surrounding span's trace_id / span_id via Context.current — no extra plumbing needed.

await tracer.startActiveSpanAsync('checkout', (span) async {
  logger.i('starting cart validation');
  // ... this record will be correlated to the checkout span
});

Knobs

Suppression

runWithoutLoggerInstrumentation(() {
  logger.i('this one will not reach OTel');
});

Inside the zone, OTelLogOutput.output short-circuits. The ConsoleOutput half (if you set up MultiOutput) still runs.

License

Apache 2.0