VTFK Logger

A simple logger for node applications. Logs to console, papertrail (via token) and Azure Function.

Installation

npm install --save @vtfk/logger

Usage

Important

Version 5.x.x and above requires Nodejs 16 or higher

Config

All options are optional.

Logging to papertrail can be configured in logConfig() or as env variables.

Logging to Microsoft Teams can be configured in logConfig() or as env variable TEAMS_WEBHOOK_URL.

Azure Function logging can be configured in logConfig().

Note: logConfig() can be called multiple times to update the config throughout the program. And it will keep the previous config parameter if not specified in the next call.

const options = {
  remote: {                     // Options for remote logging.
    disabled: false,            // If true; disables logging to remote, even if remote config is set
    onlyInProd: true,           // If true; only log to remote aggregator when NODE_ENV === 'production' (default is true)
    host: '',                   // Host for the remote aggregator
    token: '',                  // Token for the remote aggregator
    level: ''                   // Lowest level for log to remote. If not set, all levels will log to remote
  },
  teams: {                      // Options for Microsoft Teams logging with webhook.
    disabled: false,            // If true; disables logging to Microsoft Teams, even if teams config is set
    onlyInProd: true,           // If true; only log to Microsoft Teams when NODE_ENV === 'production' (default is true)
    url: '',                    // Microsoft Teams channel webhook url
    level: ''                   // Lowest level for log to Microsoft Teams. If not set, all levels will log to Microsoft Teams
  },
  azure: {                      // Options for Azure
    context: context,           // The context object received from an Azure Function (see example further down)
    excludeInvocationId: false  // If true; do not append the invocationId from the context object
  },
  prefix: '',                   // A string that will be added in front of each log message (ex. UID for each run)
  suffix: '',                   // A string that will be added at the end of each log message
  error: {                      // Options for logging out Error object. If undefined; stack from Error object will be returned
    useMessage: true            // If true; use message from Error object instead of stack
  },
  localLogger: console.log      // Replace the local logger with a custom function (Default: console.log)
}

logConfig(options)

ENV Variables

NODE_ENV=production
PAPERTRAIL_HOST = papertrail.example.com/v1/log
PAPERTRAIL_TOKEN = jvkuvuyoufyofo8ygo8f609fo7ouyvcio7=
TEAMS_WEBHOOK_URL = https://<tenant>.webhook.office.com/blablabla

logConfig() options take priority.

How to get Microsoft Teams Webhook URL

Examples

Ex. Basic

The least amount of code to log to console or a remote aggregator (if options are set in enviroment variables)

const { logger } = require('@vtfk/logger')

logger('info', ['test', 'message'])

Ex. Basic (async)

The least amount of code to log to console or a remote aggregator asynchronous (if options are set in enviroment variables)

const { logger } = require('@vtfk/logger')

await logger('info', ['test', 'message'])

Ex. Basic with specifying Error property

Use logConfig to instruct that message property is used from Error objects

const { logConfig, logger } = require('@vtfk/logger')

logConfig({
  error: {
    useMessage: true
  }
})

logger('info', ['test', 'message'])

logger('warn', ['another', 'action', new Error('Ups. Something happend')])

// OUTPUT 
// NAME-OF-APP and VER-OF-APP is the value of "name" and "version" in your package.json
[ 2019.05.19 15:41:17 ] < INFO >  {NAME-OF-APP} - {VER-OF-APP}: test - message
[ 2019.05.19 15:41:17 ] < WARN >  {NAME-OF-APP} - {VER-OF-APP}: another - action - Ups. Something happend

Ex. Basic without specifying Error property

const { logger } = require('@vtfk/logger')

logger('info', ['test', 'message'])

logger('warn', ['another', 'action', new Error('Ups. Something happend')])

// OUTPUT 
// NAME-OF-APP and VER-OF-APP is the value of "name" and "version" in your package.json
[ 2019.05.19 15:41:17 ] < INFO >  {NAME-OF-APP} - {VER-OF-APP}: test - message
[ 2019.05.19 15:41:17 ] < WARN >  {NAME-OF-APP} - {VER-OF-APP}: another - action - Error: Ups. Something happend\n

Ex. Basic with prefix

Use logConfig to display a UID infront of each message

const { logConfig, logger } = require('@vtfk/logger')
const nanoid = require('nanoid')

logConfig({
  prefix: nanoid()
})

logger('info', ['test', 'message'])

logger('warn', ['another', 'action'])

// OUTPUT 
// NAME-OF-APP and VER-OF-APP is the value of "name" and "version" in your package.json
[ 2019.05.19 15:41:17 ] < INFO >  {NAME-OF-APP} - {VER-OF-APP}: V01k3pDpHCBkAHPyCvOOl - test - message
[ 2019.05.19 15:41:17 ] < WARN >  {NAME-OF-APP} - {VER-OF-APP}: V01k3pDpHCBkAHPyCvOOl - another - action

Ex. Logging in Azure Function with context object

module.exports = async function (context, req) {
  logger('info', ['New Request. Validating token'], context) // This will log to context instead of using console.log (it will still display)
}

Ex. Logging to remote or Microsoft Teams

Configuration of remote options in the logConfig() function

const { logConfig, logger } = require('@vtfk/logger')

// logConfig() is optional
logConfig({
  remote: {
    onlyInProd: true,
    host: 'papertrail.example.com/v1/log',
    token: 'jvkuvuyoufyofo8ygo8f609fo7ouyvcio7='
  },
  teams: {
    url: 'https://<tenant>.webhook.office.com/blablabla'
  }
  prefix: 'prefixedValue',
  suffix: 'suffixedValue'
})

logger('info', ['test', 'message'])

const error = Error('Error in process')
logger('error', ['Error in app', error])

// OUTPUT
// NAME-OF-APP and VER-OF-APP is the value of "name" and "version" in your package.json
[ 2019.05.19 15:13:35 ] < INFO >  {NAME-OF-APP} - {VER-OF-APP}: prefixedValue - test - message - suffixedValue
[ 2019.05.19 15:13:35 ] < ERROR >  {NAME-OF-APP} - {VER-OF-APP}: prefixedValue - Error in app - Error: Error in process - suffixedValue

Ex. Logging to remote with a lowest level for remote or Microsoft Teams

Configuration of remote options in the logConfig() function

const { logConfig, logger } = require('@vtfk/logger')

// logConfig() is optional
logConfig({
  remote: {
    onlyInProd: true,
    host: 'papertrail.example.com/v1/log',
    token: 'jvkuvuyoufyofo8ygo8f609fo7ouyvcio7=',
    level: 'warn'
  },
  teams: {
    url: 'https://<tenant>.webhook.office.com/blablabla',
    level: 'error'
  }
  prefix: 'prefixedValue',
  suffix: 'suffixedValue'
})

// this will NOT log to remote since this level is "info" and lowest remote level is set to "warn"
logger('info', ['test', 'message'])

// this will log to remote since this level is "error" and lowest remote level is set to "warn"
const error = Error('Error in process')
logger('error', ['Error in app', error])

// OUTPUT
// NAME-OF-APP and VER-OF-APP is the value of "name" and "version" in your package.json
[ 2019.05.19 15:13:35 ] < INFO >  {NAME-OF-APP} - {VER-OF-APP}: prefixedValue - test - message - suffixedValue
[ 2019.05.19 15:13:35 ] < ERROR >  {NAME-OF-APP} - {VER-OF-APP}: prefixedValue - Error in app - Error: Error in process - suffixedValue

Ex. Disable logging to remote or Microsoft Teams

Configuration of remote options in the logConfig() function

const { logConfig, logger } = require('@vtfk/logger')

// logConfig() is optional
logConfig({
  remote: {
    disabled: true,
    onlyInProd: true,
    host: 'papertrail.example.com/v1/log',
    token: 'jvkuvuyoufyofo8ygo8f609fo7ouyvcio7='
  },
  teams: {
    disabled: true,
    url: 'https://<tenant>.webhook.office.com/blablabla'
  }
  prefix: 'prefixedValue',
  suffix: 'suffixedValue'
})

logger('info', ['test', 'message'])

const error = Error('Error in process')
logger('error', ['Error in app', error])

// OUTPUT
// NAME-OF-APP and VER-OF-APP is the value of "name" and "version" in your package.json
[ 2019.05.19 15:13:35 ] < INFO >  {NAME-OF-APP} - {VER-OF-APP}: prefixedValue - test - message - suffixedValue
[ 2019.05.19 15:13:35 ] < ERROR >  {NAME-OF-APP} - {VER-OF-APP}: prefixedValue - Error in app - Error: Error in process - suffixedValue

Ex. Azure Function

Pass the context object from Azure Function to add a invocationId and use context.log[level](message).

Note: If the context object contains all log functions (context.log[levels]) then it will log using these instead of options.localLogger

const { logConfig, logger } = require('@vtfk/logger')

module.exports = async function (context, req) {
  logConfig({
      azure: { context }, // Pass in the context. (Shorthand for 'azure: { context: context }' )
      prefix: 'kittens'
  })
  logger('error', ['are too cute!'])
  logger('warn', ['can scratch'])
  logConfig({ azure: { excludeInvocationId: true } }) // Exclude the invocationId from now on
  logger('info', ['are cats'])

  context.res.body = '200 OK'
}

// OUTPUT 
// NAME-OF-APP and VER-OF-APP is the value of "name" and "version" in your package.json
[2020-11-19T11:47:43.735Z] {NAME-OF-APP} - {VER-OF-APP}: 786df5ec-e19b-4f94-a65f-b86eed8df405 - kittens - are too cute!
[2020-11-19T11:47:43.737Z] {NAME-OF-APP} - {VER-OF-APP}: 786df5ec-e19b-4f94-a65f-b86eed8df405 - kittens - can scratch
[2020-11-19T11:47:43.737Z] {NAME-OF-APP} - {VER-OF-APP}: kittens - are cats // invocationId is now excluded

Logging

Remote logging is only enabled in a production enviroment (NODE_ENV === 'production'), unless options.remote.onlyInProd === false.

License

MIT