一个简单的日志module, 功能如下
- 时间显示
- 调用log的文件名与行号显示
- 不同日志级别使用不同颜色输出
- 支持stdout输出的同时写入文件日志
- 文件日志使用缓存以降低io次数
使用示例
var log = require(‘./log’),
logWithoutFile = log.create();
logWithFile = log.create(log.WARNING, ‘my.log’),
logWithoutFile.info(‘info msg’);
logWithoutFile.debug(‘debug msg’);
logWithoutFile.warning(‘warning msg’);
logWithoutFile.error(‘error msg’);
logWithoutFile.trace(‘trace msg’);
logWithFile.info(‘info msg’);
logWithFile.debug(‘debug msg’);
logWithFile.warning(‘warning msg’);
logWithFile.error(‘error msg’);
logWithFile.trace(‘trace msg’);
输出效果
源码如下
var fs = require(‘fs’);
var cwd = process.cwd() + '/’,
INFO = 0;
DEBUG = 1;
WARNING = 2;
ERROR = 3;
TRACE = 4;
INIT = 6;
type = ['INFO’, 'DEBUG’, 'WARNING’, 'ERROR’, 'TRACE’, '’, ‘LOG_INIT’];
colors = [38, 34, 35, 31, 32, 36, 33];
bufferSize = 20000;
writeSize = 16384;
exports.INFO = INFO;
exports.DEBUG = DEBUG;
exports.WARNING = WARNING;
exports.ERROR = ERROR;
exports.TRACE = TRACE;
function getPos() {
try {
throw new Error();
} catch(e) {
var pos = e.stack.split(‘\n’)[4].split('(')[1].split(')')[0].split(‘:’);
return pos[0].replace(cwd, ‘’) + ‘:’ + pos[1];
}
}
function pad2(num) {
return num > 9 ? num : ‘0’ + num;
}
function getTime() {
var t = new Date();
return [t.getFullYear(), '-', pad2(t.getMonth() + 1) , '-', pad2(t.getDate()), ' ',
pad2(t.getHours()), ':’, pad2(t.getMinutes()), ':’, pad2(t.getSeconds())].join(‘’);
}
function formatLog(log, color) {
var tag = head = foot = '’;
if (color) {
head = '\x1B[';
foot = '\x1B[0m’;
tag = colors[5]+’m’;
color = colors[log.type]+’m’;
}
return [log.time, ' [', head, color, type[log.type], foot, '] [', head, tag, log.pos, foot, '] ', log.msg].join(‘’);
}
exports.create = function(level, file) {
if (!level) {
level = INFO;
}
if (file) {
var buffer = new Buffer(bufferSize);
var pos = 0;
var fd = fs.openSync(file, ‘a’);
process.on('exit’, function(){
fs.writeSync(fd, buffer, 0, pos, null);
})
}
function log(type, msg) {
if (type < level){
return;
}
var log = {type:type, msg:msg, time:getTime(), pos:getPos()};
console.log(formatLog(log, true));
if (file) {
if (pos >= writeSize) {
fs.writeSync(fd, buffer, 0, pos, null);
pos = 0;
}
pos += buffer.write(formatLog(log) + "\r\n", pos);
}
}
console.log(formatLog({type:INIT, pos:file, time:getTime(), msg: 'log init with level ' + type[level]}, true));
return {
info : function(msg) {log(INFO, msg);},
debug : function(msg) {log(DEBUG, msg);},
warning : function(msg) {log(WARNING, msg);},
error : function(msg) {log(ERROR, msg);},
trace : function(msg) {log(TRACE, msg);},
};
}
