我刚刚开始使用Node.js而我现在正试图让我的脚本每隔10秒在后台运行，就像一个守护进程等待某事做，当有从数据库运行的东西时它会从中读取输出程序并根据输出执行某些任务。
这是我迄今为止所能做到的，它按照我的意图工作，但即使在后台也只能运行一次。如何让它每隔10秒就像守护进程一样运行？
代码：
var spawn = require('child_process').spawn;
var mysql = require('mysql');
var JSFtp = require('jsftp');
var check = require('node-validator').check;
var sanitize = require('node-validator').sanitize;
//Setup the db connection
var db = mysql.createConnection({
host : 'db',
port : 3306,
database: 'db',
user : 'db',
password : 'db'
});
//Make the connection
db.connect(function(err){
if(err != null) {
res.end('Error connecting to mysql:' + err+'\n');
}
});
var die = function(msg){
console.error(msg);
process.exit(1);
}
function ip2long ( ip_address ) {
var output = false;
var parts = [];
if (ip_address.match(/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/)) {
parts = ip_address.split('.');
output = ( parts[0] * 16777216 +
( parts[1] * 65536 ) +
( parts[2] * 256 ) +
( parts[3] * 1 ) );
}
return output;
}
db.query("SELECT * FROM queue WHERE cooldown > UNIX_TIMESTAMP(NOW()) AND simulated=0 ORDER BY cooldown DESC LIMIT 1", function(err, rows){
if(err != null){
die("Query error: " + err);
}
if(rows < 1){
die("No rows");
}
//Set the vars from the query
var name = rows[0]['name'];
var ip = rows[0]['ip'];
var iterations = rows[0]['runs'];
var bin = "/home/hoar/sum/run"
var args = ['arg='+name, 'arg2='+iterations, 'path=/var/www/upload/'+name+'.html', 'output=log.log'];
var proc = spawn(bin, args);
var time = "/.*/";
var pct = "/^\d/";
var name = rows[0]['name'];
var ip = rows[0]['ip'];
var iterations = rows[0]['runs'];
proc.stdout.setEncoding('utf8');
proc.stdout.on('data', function(data) {
var str = data.toString();
var s = str.split("|");
var p = s[0].split("/");
var t = (s[1] == null) ? "" : s[1];
if(p != null && s[0] != "@"){ //Needed to check for @ because the program prints this as first line, which is good then we can do the query further done only once.
//Check the return numbers from simc to see how many sims it has done
if(parseInt(p[0]) < parseInt(p[1])){
//Check if the 6th match is a number and the 7th only contains letters
if(t != null){
var time = t.replace(/(\r\n|\n|\r)/gm,""); //Remove any line disturbers for db
//Update the database with the amount of time left on the simulation
db.query("UPDATE `queue` SET `status`=" + db.escape(time) + " WHERE (`name`=" + name + ")");
//console.log(p[0]+"/"+p[1] + " - " + t + " left");
}
//console.log(p[0]+"/"+p[1] + " iterations done");
}
}else{
//If the stdout is null run this query since we don't want to run this more than once.
db.query("UPDATE `queue` SET `simulated`='2' WHERE (`name`=" + name + " AND simulated!='2')");
//console.log("Updated db to 2");
}
});
proc.stderr.on('data', function (data) {
var str = data.toString();
//If the program returns stderr we want to make sure it stops and we update the database to let the user know.
if(str.indexOf("ERROR! Setup failure...")){
//Update the database with the amount of time left on the simulation
db.query("UPDATE `queue` SET `simulated`='3' WHERE (`name`=" + name + ")");
//Kill the DB connection
db.destroy();
die("There was an error: " + data);
}
});
proc.on('exit', function (code) {
//Setup the ftp connection
var ftp = new JSFtp({
host: "ftp",
port: 21,
user: "ftp",
pass: "ftp"
});
//Simulation ended with success update the database and kill.
db.query("UPDATE `queue` SET `simulated`='1' WHERE (`name`=" + name + " AND simulated='2')");
ftp.put('/var/www/upload/'+rows[0]['name']+'.html', 'public_html/mysite/'+ip2long(rows[0]['ip'])+'/'+rows[0]['name']+'.html', function(hadError) {
if (!hadError)
console.log("FTP error");
ftp.raw.quit();
});
db.destroy();
//die("Simulation is done");
});
});//end sql
答案 0 :(得分：8)
将您的数据库查询放入具有回调的函数中，并在10秒后再次触发该函数：
function mydbquery(callback) {
db.query("SELECT * FROM queue WHERE cooldown > UNIX_TIMESTAMP(NOW()) AND simulated=0 ORDER BY cooldown DESC LIMIT 1", function(err, rows){
if(err != null){
die("Query error: " + err);
}
if(rows < 1){
die("No rows");
}
//Set the vars from the query
var name = rows[0]['name'];
var ip = rows[0]['ip'];
var iterations = rows[0]['runs'];
var bin = "/home/hoar/sum/run"
var args = ['arg='+name, 'arg2='+iterations, 'path=/var/www/upload/'+name+'.html', 'output=log.log'];
var proc = spawn(bin, args);
var time = "/.*/";
var pct = "/^\d/";
var name = rows[0]['name'];
var ip = rows[0]['ip'];
var iterations = rows[0]['runs'];
proc.stdout.setEncoding('utf8');
proc.stdout.on('data', function(data) {
var str = data.toString();
var s = str.split("|");
var p = s[0].split("/");
var t = (s[1] == null) ? "" : s[1];
if(p != null && s[0] != "@"){ //Needed to check for @ because the program prints this as first line, which is good then we can do the query further done only once.
//Check the return numbers from simc to see how many sims it has done
if(parseInt(p[0]) < parseInt(p[1])){
//Check if the 6th match is a number and the 7th only contains letters
if(t != null){
var time = t.replace(/(\r\n|\n|\r)/gm,""); //Remove any line disturbers for db
//Update the database with the amount of time left on the simulation
db.query("UPDATE `queue` SET `status`=" + db.escape(time) + " WHERE (`name`=" + name + ")");
//console.log(p[0]+"/"+p[1] + " - " + t + " left");
}
//console.log(p[0]+"/"+p[1] + " iterations done");
}
}else{
//If the stdout is null run this query since we don't want to run this more than once.
db.query("UPDATE `queue` SET `simulated`='2' WHERE (`name`=" + name + " AND simulated!='2')");
//console.log("Updated db to 2");
}
});
proc.stderr.on('data', function (data) {
var str = data.toString();
//If the program returns stderr we want to make sure it stops and we update the database to let the user know.
if(str.indexOf("ERROR! Setup failure...")){
//Update the database with the amount of time left on the simulation
db.query("UPDATE `queue` SET `simulated`='3' WHERE (`name`=" + name + ")");
//Kill the DB connection
db.destroy();
die("There was an error: " + data);
}
});
proc.on('exit', function (code) {
//Setup the ftp connection
var ftp = new JSFtp({
host: "ftp",
port: 21,
user: "ftp",
pass: "ftp"
});
//Simulation ended with success update the database and kill.
db.query("UPDATE `queue` SET `simulated`='1' WHERE (`name`=" + name + " AND simulated='2')");
ftp.put('/var/www/upload/'+rows[0]['name']+'.html', 'public_html/mysite/'+ip2long(rows[0]['ip'])+'/'+rows[0]['name']+'.html', function(hadError) {
if (!hadError)
console.log("FTP error");
ftp.raw.quit();
});
db.destroy();
//die("Simulation is done");
//NEW CODE!!!
callback();
//END OF NEW CODE
});
});//end sql
}
//NEW CODE!!!
function wait10sec(){
setTimeout(function(){
mydbquery(wait10sec);
}, 10000);
}
mydbquery(wait10sec);
//END OF NEW CODE
所以它会进行你的查询，然后在发射另一个之前等待10秒。
答案 1 :(得分：3)
让程序连续运行并使用setTimeout重新执行计时器上的主逻辑。还有setInterval这很有诱惑力，但您可能会在之前的运行完成之前开始运行。这是基本模式。
function doMainStuff() {
//do all your stuff
lastAsyncThing(function (error) {
//When your final async thing is done, start the timer
if (error) {
//log error. Maybe exit if it's irrecoverable.
}
setTimeout(doMainStuff, 10 * 1000);
});
}
//when your program starts, do stuff right away.
doMainStuff();
答案 2 :(得分：0)
永远运行此脚本包 - https://npmjs.org/package/forever
$ forever script.js
此填充在后台运行此脚本，与控制台分离。
10秒钟时间你可以使用
setInterval(function(){...}, 10*1000);
有更多信息 - http://www.w3schools.com/jsref/met_win_setinterval.asp