@livy/logger

The Livy logger factory is at the heart of every logger, as it creates a new logger instance.

Basic Example

const { createLogger } = require('@livy/logger')

const logger = createLogger('app-logger')

Installation

Install it via npm:

npm install @livy/logger

Options

The createLogger function takes a mandatory channel name as its first parameter. A second argument may be provided with object of options:

autoClose

Type: boolean

Default: true

Description: Whether to automatically run the logger's close method when the Node.js process exits / the browser page closes.

handlers

Type: Iterable<HandlerInterface | SyncHandlerInterface>

Default: []

Description: Handlers of the logger.

mode

Type: 'sync' | 'async' | 'mixed'

Default: 'mixed'

Description: The concurrency mode of the logger.

processors

Type: Iterable<ProcessorInterfaceOrFunction>

Default: []

Description: Processors of the logger.

timezone

Type: string (IANA name)

Default: The runtime's time zone, determined by the Intl API.

Description: The time zone the logger should use.

Logging

Logs can be created with the log() method. It takes a log level, a message and an optional context object:

logger.log('info', 'This is the logged message')

Note that the log method returns a Promise in async mode, so it should be awaited to avoid unexpected failures:

await logger.log('info', 'This is the logged message')

For each log level, there is a convenience method which allows omitting the level parameter:

logger.debug('This is a debug message')
logger.info('This is an info message')
logger.notice('This is a notice message')
logger.warning('This is a warning message')
logger.error('This is an error message')
logger.alert('This is an alert message')
logger.critical('This is a critical message')
logger.emergency('This is an emergency message')

Public API

reset()

Resetting a logger will reset all its handlers and processors which implement the ResettableInterface.

name (read-only)

The logger's channel name.

withName(name)

Clone the logger with a new name.

timezone (read-only)

The logger's IANA time zone name.