node如何应对sql查询导致的进程终止

zhangsheng_1992 2016-07-01 06:30:42

楼主最近在学习node开发web

基本环境如下
os centos6.5
webservice nginx port 80 前端代理
nodeservice port 9000
database mysql
frame express
view engine jade

今天在做一个列表查询的时候发现如果sql查询语句错误将会导致node进程挂掉试着用了下keepalived监控了下node的端口挂掉后重新启动有如下问题:
1.如果监听的间隔设置的太长应用可用性比较差重启前将有一段空白期
2.如果设置间隔小比如每秒都去监控的话会导致keepalived的监听进程压力过高容易导致监听进程挂掉
3.试着用了下try catch 结果不是很好

主要代码如下 router/index.js



var express = require('express');

var router = express.Router();

var model =  require('../model/model');



router.get('/', function(req, res, next) {

      res.render('index', { title: 'Express' });

});



router.get('/mysql',function(req,res,next){

    //此处的参数为requset中请求的参数

    model.query({type:'select',table: 'filmplan',where: ' versions = \'2D\'',order: 'id desc',limit: '10'},function(data,sql){

        res.render('list/list', { data: data });

    });

});

module.exports = router;

model.js



var mysql=require('mysql');

var connection = mysql.createConnection({

    host : '127.0.01',

    user : 'root',

    password : '426759',

    database : 'test',

    port:'3306'

});



connection.connect();



var query = function (condition,callback){

    var sql = createSql(condition);

    if(sql === false){

       callback(false); 

    }

    connection.query(sql,function(err,rows,fields){

        if (err) {

            connection.rollback(function() {

                throw err;

            });

        }

        callback(rows,sql);

    });

};



function createSql(condition){

    if(typeof(condition.type) == 'undefined'){

        return false;

    }

    var sql;

    switch(condition.type){

        case 'select':

            sql = select(condition);

            break;

        case 'delete':

            sql = del(condition);

            break;

        case 'update':

            sql = update(condition);

            break;

        case 'insert':

            sql = insert(condition);

            break;

        

    }

    return sql;

}



function select(condition){

    var sql = 'SELECT ';

    if(typeof(condition.filed) == 'undefined'){

        sql += '*';

    }else{

        sql += condition.filed;

    }

    if(typeof(condition.table) == 'undefined'){

        return false;

    }

    sql += ' from '+condition.table;

    if(typeof(condition.where) != 'undefined'){

        sql += ' where '+condition.where;

    }

    if(typeof(condition.group) != 'undefined'){

        sql += ' group by '+condition.order;

    }

    if(typeof(condition.order) != 'undefined'){

        sql += ' order by '+condition.order;

    }

    if(typeof(condition.limit) != 'undefined'){

        sql += ' limit '+condition.limit;

    }

    return sql;

}



exports.query = query;

list.js 模版解析一般不会出问题但还是贴出来吧



html

    title 

    body

        table.table#mytable

            tr

                td

                td

                td

                td

            each item in data

                tr

                    td= item.id

                    td= item.cenimaName

                    td= item.filmName

                    td= item.versions