Node.js in Example: Using log4js in your project...

永遠的Console Log不會是一個聰明程式設計師的選擇

Node.js的一套log套件，可以讓程式裡面的Log機制表達更完整

他包含可以針對log分等級、分類、建立不同形式的log(console, file, mail...)、幫你切割log大小、幫你House Keeping...

其中等級部分：

TRACE > DEBUG > INFO > WARN > ERROR > FATAL

其中，TRACE為最囉唆模式，顯示的LOG會包含Debug, Info, Warn, Error, Fatal等，越往右邊，所包含顯示項目越少...

下面是使用上的一些紀錄：

Install:

# npm install log4js
npm http GET https://registry.npmjs.org/log4js
npm http 304 https://registry.npmjs.org/log4js
npm http GET https://registry.npmjs.org/async/0.1.15
npm http 304 https://registry.npmjs.org/async/0.1.15
log4js@0.5.6 ../node_modules/log4js
└── async@0.1.15

File: logger.js

/**
* Usage:
* var logger = require('./logger').getInstance();
* logger.debug('TEST...123');
*/
var log4js = require('log4js')
, logger = log4js.getLogger()
, logFile = process.env.LOGPATH ? process.env.LOGPATH : '/tmp/node.log'
, logCategory = process.env.LOGCATG ? process.env.LOGCATG : 'normal'
, logLevel = process.env.LOGLEVEL ? process.env.LOGLEVEL : 'DEBUG'
, logMaxSize = process.env.LOG_MAX_SIZE ? process.env.LOG_MAX_SIZE : 20480
, logBackup = process.env.LOG_BACKUP ? process.env.LOG_BACKUP : 7;
log4js.configure(
{
"appenders": [
{ type: 'console' },
{
"type": "file",
"filename": logFile,
"maxLogSize": logMaxSize,
"backups": logBackup,
"category": logCategory
}
]
}
);
var logger = log4js.getLogger(logCategory);
logger.setLevel(logLevel);
exports.getInstance = function() {
return logger;
}

File: test.js

var logger = require('./logger').getInstance();
logger.trace('[trace]....');
logger.debug('[debug]....');
logger.info('[info]....');
logger.warn('[warn]....');
logger.error('[error]....');
logger.fatal('[fatal]....');