olog

Opinionated Logging for Node.js - forces prescriptive, disciplined, structured logging.

Install

Install with:

npm install olog --save

Usage

To get started require olog passing your module var. This will automatically use your module to include the component name in your logs.

const log = require('olog')(module)

To configure logging for your application, call the config function in the top-level module.

log.config({
  application: 'product-service',
  environment: 'dev'
})

To log a server informational log, pass in a log record (javascript object) with fields.

let productId = '123'

log.info({
  message: `Db Update on Product ${productId}`,
  category: 'Catalog'
  transaction: 'CreateProduct',
  trace: 'e45dc587-3516-489f-9487-391a119889c0'
  annotations: {
    productId: productId
  }
})

Outputs:

{
  "time": "2016-11-01T23:00:35.181Z",
  "message": "[SERVER-Info] Db Update on Product 123",
  "level": "Info",
  "schema": "SERVER-Info",
  "version": 3,
  "host": "i-a38273",
  "pid": "28393",
  "component": "lib/mymodule",
  "category": "Catalog",
  "transaction": "CreateProduct",
  "trace": "e45dc587-3516-489f-9487-391a119889c0",
  "annotations": {
    "productId": "123"
  }
}

API

• olog (options)
• log.config (options)
• log.debug (record)
• log.info (record)
• log.warn (record)
• log.error (record)
• log.serverDebug (record)
• log.serverInfo (record)
• log.serverWarn (record)
• log.serverError (record)
• log.clientDebug (record)
• log.clientInfo (record)
• log.clientWarn (record)
• log.clientError (record)
• log.httpApiStart (record)
• log.httpApiStop (record)
• log.httpUiStart (record)
• log.httpUiStop (record)
• log.httpApiSend (record)
• log.httpApiReceive (record)
• log.eventStart (record)
• log.eventStop (record)

olog (module[, defaults])

Factor function that creates a new logger. It makes it easy to require and create a logger for a module.

module

Type: String or Object

If module is a String, it will be component in log records. If module is an Object, it should be Node's module Object. The the component will be generated based on its properties.

defaults

Type: Object

Allows you to provide module-level defaults for any of the log record properties (i.e. category, transaction, etc).

Examples

// component name
const log = require('my-module')  

or

// generates component name
const log = require(module)

or

// applies record defaults
const log = require(module, {
  category: 'Shopping Cart',
  transaction: 'UpdateCart'
})

log.config (options)

Configure application-wide settings for logging.

options

Type: Object

options.application

Type: String Environment Variable: OLOG_APPLICATION

options.environment

Type: String Environment Variable: OLOG_ENVIRONMENT

options.level (process.env.OLOG_LEVEL)

Type: String Environment Variable: OLOG_LEVEL

options.stream

Type: Stream

options.messageTemplates

Type: Object

log.debug (record)

Alias for log.serverDebug (record).

log.info (record)

Alias for log.serverInfo (record).

log.warn (record)

Alias for log.serverWarn (record).

log.error (record)

Alias for log.serverError (record).

log.serverDebug (record)

log.serverInfo (record)

log.serverWarn (record)

log.serverError (record)

log.clientDebug (record)

log.clientInfo (record)

log.clientWarn (record)

log.clientError (record)

log.httpApiStart (record)

log.httpApiStop (record)

log.httpUiStart (record)

log.httpUiStop (record)

log.httpApiSend (record)

log.httpApiReceive (record)

log.eventStart (record)

log.eventStop (record)