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autotel

Logging

Pino is the recommended first-class logger for autotel. Bunyan and Winston also work via OpenTelemetry auto-instrumentation.

Section titled “Pino (Recommended)”

Pino is first-class: pass a single instance to init() for both autotel internal logs and app logs.

import pino from 'pino';
import { init, trace } from 'autotel';


const logger = pino({
  name: 'my-app',
  level: 'info',
  transport: {
    target: 'pino-pretty',
    options: { colorize: true },
  },
});


// One logger for autotel + app logs
init({
  service: 'my-app',
  logger,
  endpoint: process.env.OTLP_ENDPOINT,
});


const createUser = trace((ctx) => async (name: string) => {
  logger.info({ name }, 'Creating user');
  // trace_id, span_id automatically injected into log output
  const user = await db.users.create({ name });
  logger.info({ userId: user.id }, 'User created');
  return user;
});

Log Output

Section titled “Log Output”
{
  "level": 30,
  "time": 1700000000000,
  "msg": "Creating user",
  "name": "Alice",
  "trace_id": "a1b2c3d4e5f6",
  "span_id": "1234567890ab"
}

Bunyan

Section titled “Bunyan”

Use auto-instrumentation for trace context injection:

instrumentation.ts
import { init } from 'autotel';


init({
  service: 'my-app',
  autoInstrumentations: ['bunyan'],
});
import bunyan from 'bunyan';


const logger = bunyan.createLogger({ name: 'my-app' });


// trace_id, span_id automatically added to every log record
logger.info({ userId: '123' }, 'Processing request');

Winston

Section titled “Winston”
instrumentation.ts
import { init } from 'autotel';


init({
  service: 'my-app',
  autoInstrumentations: ['winston'],
});
import winston from 'winston';


const logger = winston.createLogger({
  transports: [new winston.transports.Console()],
});


// trace_id, span_id automatically added
logger.info('Processing request');

Request Logger vs Pino

Section titled “Request Logger vs Pino”

They serve different purposes:

| Feature | getRequestLogger() | Pino/Bunyan/Winston | | -------- | --------------------------------- | ----------------------------- | | Purpose | One wide event per request | Continuous structured logging | | Output | Attributes on the span | Log stream (stdout/files) | | When | .emitNow() at end of request | Throughout request | | Use case | Canonical log lines / wide events | Debugging, audit trails |

Use both together: Pino for continuous logging + getRequestLogger() for the one snapshot at the end of each request.

Examples

Section titled “Examples”