I just started using Node.js and I'm now trying to make my script run in the background every 10 seconds like a daemon waiting for something to do, when there is something to run from the database It reads the output from the program and does certain tasks depending on the output.
This is what I've been able to do so far, It works just as I intended but can only run once even in the background. How can I make it run like a daemon every 10 seconds?
Code:
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
I just started using Node.js and I'm now trying to make my script run in the background every 10 seconds like a daemon waiting for something to do, when there is something to run from the database It reads the output from the program and does certain tasks depending on the output.
This is what I've been able to do so far, It works just as I intended but can only run once even in the background. How can I make it run like a daemon every 10 seconds?
Code:
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
-
Not sure you care - but your IP regex is not very accurate - it'll gladly accept
999.999.999.999for example. – Benjamin Gruenbaum Commented Jan 30, 2014 at 15:53 -
So you want to execute the
db.query("SELECT * FROM queue ...with it's success callback every 10 sec? – t.niese Commented Jan 30, 2014 at 15:54 - Thanx for the tip Benjamin! – user3246446 Commented Jan 30, 2014 at 16:59
3 Answers
Reset to default 11Put your db query in a function with callback, and make the callback fire the function again 10sec later:
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
So it will do your query, then wait 10sec before firing another.
Just have your program run continuously and use setTimeout to re-execute the main logic on a timer. There is also setInterval which is tempting but you risk starting a run before the prior run pletes. Here's the basic pattern.
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();
run this script by forever package - https://npmjs/package/forever
$ forever script.js
This fill run this script in background, detached from console.
For 10 seconds timeuout you can use
setInterval(function(){...}, 10*1000);
More info is there - http://www.w3schools./jsref/met_win_setinterval.asp