ackee-node-logger

Simple pino-based logger setup for Ackee purposes

How to use

First step is to create a root logger. Its configuration can be specified on creation and it will be used for all other loggers created.

Create root logger with default configuration

const logger = require('ackee-node-logger');
// or
const logger = require('ackee-node-logger')();

Create root logger with custom configuration

const logger = require('ackee-node-logger')({
    disableFields: ['error.stack'],
    enableFields: ['req.protocol']
});

Note: If you want to specify custom configuration it must be done in the first require of ackee-node-logger. Otherwise, default configuration will be used.

See Options for a list of possible options.

After you create a root logger, you may use it or you can create a child logger.

const databaseLogger = require('ackee-node-logger')('database')

The only difference between root logger and a child logger is that the child logger will print its name in each log message.

Logger usage

Logger itself is an enhanced and specifically configured pino instance, so you may use all basic pino log methods

logger.info('hello world')
logger.error('this is at error level')
logger.info('the answer is %d', 42)
logger.info({ obj: 42 }, 'hello world')
logger.info({ obj: 42, b: 2 }, 'hello world')
logger.info({ obj: { aa: 'bbb' } }, 'another')

All pino levels are supported and additionaly there is a warning level which is equivalent to warn level.

Default minimal log level is debug.

All loglevels up to warning (exclusive) - trace, debug and info - are logged to stdout only.

All loglevels from warning up (inclusive) - warning, error, fatal - are logged to stderr only.

Express middleware

ackee-node-logger contains an express middleware which you can use to log all requests and responses of your express application.

Usage:

const express = require('express');
const logger = require('ackee-node-logger');

const app = express();
// or
const router = express.Router();

app.use(logger.express)
// or
router.use(logger.express)

By default, it will log all incoming requests in debug level, all outcoming responses with out property in debug level and all outcoming responses without out property on info level.

If you use it together with logger's error express middleware, it will also log all errors in error level.

app.use(logger.expressError)

All those log messages will contain request and possibly response, error, time from request to response and status code.

Environment-specific behavior

ackee-node-logger is meant to be used throughout different environments (development, testing, production) and some of its configuration is setup differently based on the environment it runs in.

Testing

If the NODE_ENV environment variable is set to test, all logs are turned off (minimal loglevel is set to silent which effectively turns logging off).

Otherwise

Standard pino log is used and it's optimized for Google Stackdriver logging. That means that default log level is debug, pretty print is turned off and pino's messageKey option is set to message.

Options

Options override both default logger configuration and environment-specific configuration. However, do not forget to specify it during the first ackee-node-logger. During it, root logger is created and it cannot be changed later.

• defaultLevel - set logger's minimal loglevel (default is debug)
• disableFields - list of paths which will be omitted from the objects being logged (if any)
• enableFields - list of paths which will not be omitted by default serializers from objects being logged
• streams - list of stream objects, which will be passed directly to pino-multistream's multistream function instead of default ackee-node-logger stream
• pretty - if set to true, logger will use pino pretty human-readable logs. This option can be overriden by streams
• config - object, which will be passed to underlying logger object. Right now, underlying logger is pino, so for available options see pino API docs

Default serializers

ackee-node-logger defines some pino serializers on its own

• error - logs message, code, stack and data fields
• processEnv - logs NODE_PATH and NODE_ENV
• req - logs body, query, url, method and omits password and passwordCheck from body and query
• res - logs out and time

Tips

VS Code debugging not showing log messages

This problem is caused by a way VS Code handles console output. Therefore it appears in Winston and pino (underlying library of ackee-node-logger) as well.

However, it can be easily solved by adding eithe

"console": "integratedTerminal",

or

"outputCapture": "std"

to the debug configuration in your launch.json file.