@intellihr/lambda-logger

Lambda Logger

A logger which complies with our logging standard (see Logging Format)

Get Started

1. Install

   yarn add @intellihr/lambda-logger
   # or
   npm i @intellihr/lambda-logger

2. Usage

   import { logger } from '@intellihr/lambda-logger'

Environment Variables

Logger uses environment variables to set default values. These are optional.

Available variables:

Name	Default	Available Values	Description
LOGGING_LEVEL	null	emerg,alert,crit, err, warning, notice, info, debug	If set, log only if level less than or equal to this level (see: Logging Level)
LOGGING	console	console, file	This is where the logger puts its output.
LOG_FILE_LOCATION	./output/log.txt	Any valid path in string	Only used when LOGGING=file. The path where the output log is stored
SERVICE	null	string	Set default value for service
STAGE	null	string	Set default value for environment
HOST	null	string	Set default value for host
REGION	null	string	Set default value for region
IS_OFFLINE	null	string	If not set, it will output the log using stdout to avoid extra prefix in AWS Lambda

For serverless, you can set the environment variables in the serverless.yml

provider:
  environment:
    LOGGING_LEVEL: ${env:LOGGING_LEVEL, 'info'}
    LOGGING: ${env:LOGGING, 'console'}
    SERVICE: ${self:service}
    STAGE: ${self:custom.stage}
    REGION: ${self:custom.region}

Logging Level

const levelMap = {
  emerg: 0,
  alert: 1,
  crit: 2,
  err: 3,
  warning: 4,
  notice: 5,
  info: 6,
  debug: 7
}

Logger Options

These are accepted as part of our standard (see Logging Format)

const {
  level,
  service,
  environment,
  region,
  host,
  timestamp,
  user,
  path,
  tags,
  status,
  message,
  data,
  tenant
} = options

logger.log(options)
// or
logger(options).log()

Logger Methods

See Logger Options for all the accepted options

import { logger } from '@intellihr/lambda-logger'

logger.emergency('message', options)
logger.alert('message', options)
logger.critical('message', options)
logger.error('message', options)
logger.warning('message', options)
logger.notice('message', options)
logger.info('message', options)
logger.debug('message', options)
logger.log(options)

Usage

See Logger Options for all the accepted options

See Logger Methods for all the available methods

Simple:

import { logger } from '@intellihr/lambda-logger'

// The belows are printing the same log
// case 1
const myLogger = logger({ tags: ['test'] })
myLogger.info('This is info')

// case 2
logger.info('This is info', { tags: ['test'] })

// case 3
logger.log({ level: 'info', tags: ['test'], message: 'This is info'})

// case 4
const myLogger = logger({ tags: ['test'] })
myLogger.log({ level: 'info', message: 'This is info'})

Advanced:

import { logger } from '@intellihr/lambda-logger'

const testLog = logger({ tags: ['test'] })

const logInfo = testLog.info
const logError = testLog.error

// Both with tags: ['test']
logInfo('This is info')
logError('This is error')

Example to create your own logger:

import { logger } from '@intellihr/lambda-logger'

class MyLogger {
  constructor (options) {
    this._logger = logger({
      service: 'my-service',
      ...options
    })
  }

  info (options) {
    this._logger.info(options)
  }
}

// This will attach both service and tags
const myLogger = newLogger({ tags: ['oh-my'] })
myLogger.info('This is an info')

Local Development

Run inside docker

docker-compose run --rm code /bin/sh
# or without mounting node_module
docker-composer run --rm code-mac /bin/sh

Test

yarn test

Lint

yarn lint