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()
}