// origin author :fengyin <[email protected]>
// modified by : sumory <[email protected]>

var fs = require('fs');
var config = require('../config.js').config;

var FILE_SPLIT_INTERVAL = 'DAY';// 1d
var BUFFER_CHECK_INTERVAL = 2000;// 2s
var BUFFER_FLUSH_LEN = 512;
var LOG_DIRECTORY = config.logDirectory;

var fileMap = {
    'info' : {
        pathPrefix : 'info.log.'
    },
    'error' : {
        pathPrefix : 'error.log.'
    },
    'exception' : {
        pathPrefix : 'exception.log.'
    }
};

// initial setting
var curDay = (new Date()).getDate();

function genFilePostfix() {
    var dnow = new Date();
    return dnow.format('yyyy-mm-dd');
}

function genTimeStamp() {
    var dnow = new Date();
    return dnow.format('HH:MM:ss');
}

function debug(str) {
    console.log(str);
}

function inspect(obj) {
    console.log(require('util').inspect(obj, false, 10));
}

function LogFile(options) {
    this.pathPrefix = options.pathPrefix;

    this.buffers = [];
    this.bufferCheckInterval = options.bufferCheckInterval
            || BUFFER_CHECK_INTERVAL;

    this.init();
}

LogFile.prototype.push = function(str) {
    this.buffers.push(str);
    if (this.buffers.length >= BUFFER_FLUSH_LEN) {
        this._flush();
    }
};

LogFile.prototype._flush = function() {
    if (this.buffers.length > 0 && this.stream) {
        this.buffers.push('');
        var str = this.buffers.join('\n');
        this.stream.write(str);
        // debug('buffers length: ' + this.buffers.length);
        this.buffers = [];
    }
};

LogFile.prototype.destroy = function() {
    this._flush();

    if (this.bufferCheckTimer) {
        clearInterval(this.bufferCheckTimer);
        this.bufferCheckTimer = null;
    }
    if (this.stream) {
        this.stream.end();
        this.stream.destroySoon();
        this.stream = null;
    }
};

LogFile.prototype.init = function() {
    // debug('log init ' + this.pathPrefix);
    var self = this;
    var path = LOG_DIRECTORY + this.pathPrefix + genFilePostfix();
    // debug(path);
    // inspect(conf);
    this.stream = fs.createWriteStream(path, {
        flags : 'a'
    });

    this.bufferCheckTimer = setInterval(function() {
        self._flush();
    }, this.bufferCheckInterval);
};

LogFile.prototype.restart = function() {
    this.destroy();
    this.init();
};

var logMap = {};

// exports.init = function(){
for ( var id in fileMap) {
    logMap[id] = new LogFile(fileMap[id]);
}
// }

function push2File(str, id) {
    var logFile = logMap[id];

    var dnow = new Date();
    if (dnow.getDate() != curDay) {
        // if(dnow.getMinutes() != curMinute){
        logFile.restart();
        curDay = dnow.getDate();
        // curMinute = dnow.getMinutes();
    }
    logFile.push(dnow.format('HH:MM:ss') + '\t' + str);
}

exports.info = function(str) {
    push2File(str, 'info');
};

exports.error = function(str) {
    push2File(str, 'error');
};

exports.exception = function(str) {
    push2File(str, 'exception');
};

文件是按天记录的，按自己的业务稍微改下就可以用了，

var log = require('log.js');
log.error('...');
log.exception('...');
log.info('...');

@baryon 这个基本上是我从itier上挖的，然后根据需要改造了下（具体与业务联系的已经被我删了才粘上来的），已经标明原作者了。代码本来就是开放的，小东西，随便用。