morgan

HTTP request logger middleware for node.js

morgan

HTTP request logger middleware for node.js

Named after Dexter, a show you should not watch until completion.

var morgan = require('morgan')

Create a new morgan logger middleware function using the given format and options. The format argument may be a string of a predefined name (see below for the names), a string of a format string, or a function that will produce a log entry.

Morgan accepts these properties in the options object.

Write log line on request instead of response. This means that a requests will be logged even if the server crashes, but data from the response (like the response code, content length, etc.) cannot be logged.

Function to determine if logging is skipped, defaults to false. This function will be called as skip(req, res).

// EXAMPLE: only log error responses 
morgan('combined', {
  skipfunction (reqres) { return res.statusCode < 400 }
})

Output stream for writing log lines, defaults to process.stdout.

There are various pre-defined formats provided:

Standard Apache combined log output.

:remote-addr - :remote-user [:date[clf]] ":method :url HTTP/:http-version" :status :res[content-length] ":referrer" ":user-agent"

Standard Apache common log output.

:remote-addr - :remote-user [:date[clf]] ":method :url HTTP/:http-version" :status :res[content-length]

Concise output colored by response status for development use. The :status token will be colored red for server error codes, yellow for client error codes, cyan for redirection codes, and uncolored for all other codes.

:method :url :status :response-time ms - :res[content-length]

Shorter than default, also including response time.

:remote-addr :remote-user :method :url HTTP/:http-version :status :res[content-length] - :response-time ms

The minimal output.

:method :url :status :res[content-length] - :response-time ms

To define a token, simply invoke morgan.token() with the name and a callback function. This callback function is expected to return a string value. The value returned is then available as ":type" in this case:

morgan.token('type', function(reqres){ return req.headers['content-type']; })

Calling morgan.token() using the same name as an existing token will overwrite that token definition.

The current date and time in UTC. The available formats are:

  • clf for the common log format ("10/Oct/2000:13:55:36 +0000")
  • iso for the common ISO 8601 date time format (2000-10-10T13:55:36.000Z)
  • web for the common RFC 1123 date time format (Tue, 10 Oct 2000 13:55:36 GMT)

If no format is given, then the default is web.

The HTTP version of the request.

The HTTP version of the request.

The Referrer header of the request. This will use the standard mis-spelled Referer header if exists, otherwise Referrer.

The remote address of the request. This will use req.ip, otherwise the standard req.connection.remoteAddress value (socket address).

The user authenticated as part of Basic auth for the request.

The given header of the request.

The given header of the response.

The time between the request coming into morgan and when the response headers are written, in milliseconds.

The status code of the response.

The URL of the request. This will use req.originalUrl if exists, otherwise req.url.

The contents of the User-Agent header of the request.

Simple app that will log all request in the Apache combined format to STDOUT

var express = require('express')
var morgan = require('morgan')
 
var app = express()
 
app.use(morgan('combined'))
 
app.get('/', function (reqres) {
  res.send('hello, world!')
})

Simple app that will log all request in the Apache combined format to STDOUT

var finalhandler = require('finalhandler')
var http = require('http')
var morgan = require('morgan')
 
// create "middleware" 
var logger = morgan('combined')
 
http.createServer(function (reqres) {
  var done = finalhandler(req, res)
  logger(req, res, function (err) {
    if (err) return done(err)
 
    // respond to request 
    res.setHeader('content-type', 'text/plain')
    res.end('hello, world!')
  })
})

Simple app that will log all requests in the Apache combined format to the file access.log.

var express = require('express')
var fs = require('fs')
var morgan = require('morgan')
 
var app = express()
 
// create a write stream (in append mode) 
var accessLogStream = fs.createWriteStream(__dirname + '/access.log', {flags: 'a'})
 
// setup the logger 
app.use(morgan('combined', {stream: accessLogStream}))
 
app.get('/', function (reqres) {
  res.send('hello, world!')
})

Simple app that will log all requests in the Apache combined format to one log file per date in the log/ directory using the file-stream-rotator module.

var FileStreamRotator = require('file-stream-rotator')
var express = require('express')
var fs = require('fs')
var morgan = require('morgan')
 
var app = express()
var logDirectory = __dirname + '/log'
 
// ensure log directory exists 
fs.existsSync(logDirectory) || fs.mkdirSync(logDirectory)
 
// create a rotating write stream 
var accessLogStream = FileStreamRotator.getStream({
  filename: logDirectory + '/access-%DATE%.log',
  frequency: 'daily',
  verbose: false
})
 
// setup the logger 
app.use(morgan('combined', {stream: accessLogStream}))
 
app.get('/', function (reqres) {
  res.send('hello, world!')
})

Sample app that will use custom token formats. This adds an ID to all requests and displays it using the :id token.

var express = require('express')
var morgan = require('morgan')
var uuid = require('node-uuid')
 
morgan.token('id', function getId(req) {
  return req.id
})
 
var app = express()
 
app.use(assignId)
app.use(morgan(':id :method :url :response-time'))
 
app.get('/', function (reqres) {
  res.send('hello, world!')
})
 
function assignId(reqresnext) {
  req.id = uuid.v4()
  next()
}

MIT