Logs for trace and debug levels are not printed when using a custom formatters.level in Pino 9.5.0

[jenishk29]

I’m facing an issue with my current Pino logger setup where logs for trace and debug levels are not being printed. Here’s a quick summary of the setup and problem:

Initial Setup:
Create a logger module named @pino-logger.

import { randomUUID } from 'node:crypto';
import pino from 'pino';

export const logger = pino(
  {
    enabled: !process?.env?.NOLOG,
    base: {
      traceId: randomUUID(),
      userId: 'undefined',
      source: process?.env?.AWS_LAMBDA_FUNCTION_NAME,
      requestId: 'undefined',
    },
    level: process?.env?.LOG_LEVEL || 'trace',
    redact: {
      paths: process.env.PATHS_TO_MASK_DATA?.split(',') || [],
      censor: '******',
    },
    timestamp: () => `,"timestamp":"${new Date(Date.now()).toISOString()}"`,
  },
  pino.destination({ sync: true }),
);

Usage in AWS Lambda Function:
Import and use the logger in a Lambda function.

import { logger } from '@pino-logger';
logger.trace('getCustomerProfile %s', customerId);

This setup correctly prints all log levels, including trace. Sample log:

{
    "level": 10,
    "timestamp": "2024-11-19T07:00:06.685Z",
    "traceId": "b61e86c6-f067-44ca-82ec-f0b057db7940",
    "userId": "anonymous",
    "source": "get-customer-profile",
    "requestId": "b37109f1-353b-4e30-a649-fe38a22cea4d",
    "msg": "GetCustomerProfile: 1879999002"
}

Updated Setup with formatters.level:
Modify the logger to replace numerical levels (e.g., 10) with their string equivalents (e.g., 'TRACE').

export const logger = pino(
  {
    enabled: !process?.env?.NOLOG,
    base: {
      traceId: randomUUID(),
      userId: 'undefined',
      source: process?.env?.AWS_LAMBDA_FUNCTION_NAME,
      requestId: 'undefined',
    },
    level: process?.env?.LOG_LEVEL || 'trace',
    formatters: {
      level: (label) => ({
        level: label.toUpperCase(),
      }),
    },
    redact: {
      paths: process.env.PATHS_TO_MASK_DATA?.split(',') || [],
      censor: '******',
    },
    timestamp: () => `,"timestamp":"${new Date(Date.now()).toISOString()}"`,
  },
  pino.destination({ sync: true }),
);

After this update, logs for trace and debug levels are no longer printed. However, other levels, such as info and error, work as expected.

Example of working log:

{
    "level": "ERROR",
    "timestamp": "2024-11-18T21:04:51.312Z",
    "traceId": "292aa1db-a2d4-4949-8394-5e292f52081d",
    "userId": "undefined",
    "source": "get-customer-profile",
    "requestId": "undefined",
    "msg": "error"
}

1. Is there something wrong with my current logger configuration or formatters.level usage?
2. How can I modify the setup to ensure that trace and debug logs are printed while maintaining formatted log levels (e.g., 'TRACE', 'DEBUG')?