Node.js 模块之 morgan中间件记录日志

NodeJs中Express框架使用morgan中间件记录日志

Express中的app.js文件已经默认引入了该中间件var logger = require(\'morgan\');

使用app.use(logger(\'dev\'));可以将请求信息打印在控制台，便于开发调试，但实际生产环境中，需要将日志记录在log文件里，可以使用如下代码

    var express = require(\'express\');  
    var fs = require(\'fs\');  
    var logger = require(\'morgan\');  
      
    var app = express();  
      
    var accessLog = fs.createWriteStream(\'../access.log\', {flags : \'a\'});  
    var errorLog = fs.createWriteStream(\'../error.log\', {flags : \'a\'});  
      
    app.use(logger(\'dev\'));     //打印到控制台  
    app.use(logger(\'combined\', {stream : accessLog}));      //打印到log日志  

 

这样便可以将请求信息打印在根目录下的access.log文件中（注意文件路径别填错，并不会自动创建该文件）

 

示例：

express/connect

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

Log出所有Apache请求（结合STTDOUT格式）

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

 

vanilla http server

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 (req, res) {
  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!\')
  })
})

 

write logs to a file

single file

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

Log列出所有Apache请求到access.log中

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

 

log file rotation

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

每天将所有Apache请求记录到log中

var express = require(\'express\')
var fs = require(\'fs\')
var morgan = require(\'morgan\')
var path = require(\'path\')
var rfs = require(\'rotating-file-stream\')
 
var app = express()
var logDirectory = path.join(__dirname, \'log\')
 
// ensure log directory exists
fs.existsSync(logDirectory) || fs.mkdirSync(logDirectory)
 
// create a rotating write stream
var accessLogStream = rfs(\'access.log\', {
  interval: \'1d\', // rotate daily
  path: logDirectory
})
 
// setup the logger
app.use(morgan(\'combined\', {stream: accessLogStream}))
 
app.get(\'/\', function (req, res) {
  res.send(\'hello, world!\')
})

 

split / dual logging

The morgan middleware can be used as many times as needed, enabling combinations like:

• Log entry on request and one on response
• Log all requests to file, but errors to console
• ... and more!

Sample app that will log all requests to a file using Apache format, but error responses are logged to the console:

Log所有Apache请求，错误Log到console中

var express = require(\'express\')
var fs = require(\'fs\')
var morgan = require(\'morgan\')
var path = require(\'path\')
 
var app = express()
 
// log only 4xx and 5xx responses to console
app.use(morgan(\'dev\', {
  skip: function (req, res) { return res.statusCode < 400 }
}))
 
// log all requests to access.log
app.use(morgan(\'common\', {
  stream: fs.createWriteStream(path.join(__dirname, \'access.log\'), {flags: \'a\'})
}))
 
app.get(\'/\', function (req, res) {
  res.send(\'hello, world!\')
})

 

use custom token formats

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

ID Token格式

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 (req, res) {
  res.send(\'hello, world!\')
})
 
function assignId (req, res, next) {
  req.id = uuid.v4()
  next()
}