Inserting data into mongodb using time comparison - node.js

Question

Suppose I have this code running on 3 different servers and every server is using a single database.
setInterval(function(){
if(userArray) {
var report = mongoose.connection.db.collection('report');
report.insert({datenow:new Date(),userlist:userArray},function(err,doc) {
if(err) throw err;
});
}
},600000);
So, this piece of code is running every 10 minutes on every server but I want only one of them to insert the data into the database. Since the data is same it is getting inserted 3 times.
How do I check if the data is already inserted into the database by any one of the servers.
I tried making an incrementing count variable and insert it into the database and use it as a unique ID to check if it exists in the database. If it exists then I won't insert the data. But what if I have to restart the server for some reason, then the count will be reset to its initial value and this doesn't seem a viable solution.
So, how do I approach this problem? I am guessing I have to compare time somehow?

Answer 1

IMO, you should use a Cron expression instead of interval and use the execution time as primary key of your report when you perform the insertion in the database.
Explanation
Cron expression can garantee that the execution of your script will occur at an accurate time. If you use this Cron expression : 00 */10 * * * * (every 10 minutes), your script will execute at exactly 11:00:00, 11:10:00, 11:20:00, so on.. for every server you have.
So you can use this execution time as key for your reports and it will prevent multiple insertion of the same report.
Libs
You can use this lib to use Cron with Node.js : node-cron
Example
var CronJob = require('cron').CronJob;
new CronJob('* * * * * *', function() {
console.log('You will see this message every second');
}, null, true, 'America/Los_Angeles');
I hope this will help you.

Answer 2

So I had to end up comparing timestamps and checking it anything is inserted in the last 10 minutes. This is the solution I came up with.
setInterval(function(){
var currDate = new Date().getTime();
if(keyPairNameArray) {
var overallreport = mongoose.connection.db.collection('overallreport');
overallreport.find({}).sort({_id:-1}).limit(1).toArray(function(err, res){
if(res.length > 0){
var dbDate = new Date(res[0].datenow).getTime();
var diffDate = currDate - dbDate;
if(diffDate < 600000){
} else {
overallreport.insert({datenow:new Date(),userlist:keyPairNameArray},function(err,doc) {
if(err) throw err;
});
}
} else {
overallreport.insert({datenow:new Date(),userlist:keyPairNameArray},function(err,doc) {
if(err) throw err;
});
}
});
}
},610000);