bitnacle-express

bitnacle-express is a dead simple middleware logger to use with Express apps.

It is compatible with request-ip and express-request-id, if you are using them make sure to use bitnacle-express after them.

Installation

npm i bitnacle-express

Quick start

const app = require('express')();
const bitnaclExpress = require('bitnacle-express');

app.use(bitnaclExpress.logger()); // use default "simple" format 

Usage

• Log incoming HTTP requests using logger:

  You can specify 3 different formats: simple (default), json and extended

  app.use(bitnaclExpress.logger({
      format: 'json' // optional: default is "simple"
  }));  

  These are the outputs for the 3 different formats, simple, json and extended respectively:

  [2020-05-28T00:53:13:658+0200] [INFO] [GET] [/] [::1] [Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.61 Safari/537.36] [cd820302-740b-4f30-8a68-a4348c68bdd9] [304] [9ms]

  {"time":"2019-08-25T17:04:47:603+0200","level":"INFO","method":"GET","endpoint":"/","remoteAddress":"::1","id":"6c09133d-ffa3-4ad3-af3b-8e5c78ee73ad","statusCode":304,"elapsedTime":"18ms"}

  { 
      time: '2019-08-25T17:13:52:079+0200',
      level: 'INFO',
      hostname: 'localhost',
      req: { 
          method: 'GET',
          endpoint: '/',
          headers: { 
              host: 'localhost:3100',
              connection: 'keep-alive',
              'cache-control': 'max-age=0',
              'upgrade-insecure-requests': '1',
              'user-agent':
              'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36',
              'sec-fetch-mode': 'navigate',
              'sec-fetch-user': '?1',
              accept:
              'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3',
              'sec-fetch-site': 'none',
              'accept-encoding': 'gzip, deflate, br',
              'accept-language': 'es-ES,es;q=0.9,en;q=0.8',
              cookie: 'io=ohrfY8fxk-ZqSXbYAAAC',
              'if-none-match': 'W/"424-gtDsLN/eQBxV76fISNK6wSdFMmY"' 
          },
          remoteAddress: '::1',
          params: 0,
          query: 0,
          id: '9ff20b68-f46d-4eb5-9ef3-9cb077de1677' 
      },
      statusCode: 200,
      elapsedTime: '2ms' 
  }

  IMPORTANT: As noted before, if you are using request-ip and/or express-request-id in your app, you must use bitnacle-express after them:

  const app = require('express')();
  
  ... 
  
  app.use(requestIp.mw())
  app.use(addRequestId())
  app.use(bitnaclExpress.logger())

• Log errors using errorLogger

  The errorLogger only supports the simple and json formats. Your app must use it after the routes declaration.

  const router = require('./router');
  
  app.use(router);
  
  app.use(bitnaclExpress.errorLogger({
      format: 'json' // optional: default is "simple"
  }));

  IMPORTANT: errorLogger doesn't handle the errors/exceptions, it only logs them, so place it before your error handlers.

  I personally recommend to try/catch your routes and handle errors locally unless you have a general handler for some or all of your routes. You can use Bitnacle logger along with bitnacle-express to log your errors on the catch block of your routes.

Log levels

bitnacle-express.logger will use predefined log levels based on the response.statusCode.

• statusCode >= 500 will use [ERROR] level
• statusCode >= 400 will use [WARNING] level
• statusCode >= 100 will use [INFO] level

Log to stream files

In order to log to files, you must create streams and pass them to bitnacle. You can add as many streams as you want:

const router = require('./router');

const writableStream = fs.createWriteStream('./access.log', { flags: 'a' });

app.use(router);

app.use(bitnaclExpress.errorLogger({
    streams: [
        writableStream
    ]
}));