一个简单的日志module

  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);}, }; }