How to listen for changes to a MongoDB collection?

Question

I\'m creating a sort of background job queue system with MongoDB as the data store. How can I \"listen\" for inserts to a MongoDB collection before spawning workers to proce

Answer 1

MongoDB version 3.6 now includes change streams which is essentially an API on top of the OpLog allowing for trigger/notification-like use cases.

Here is a link to a Java example: http://mongodb.github.io/mongo-java-driver/3.6/driver/tutorials/change-streams/

A NodeJS example might look something like:

 var MongoClient = require('mongodb').MongoClient;
    MongoClient.connect("mongodb://localhost:22000/MyStore?readConcern=majority")
     .then(function(client){
       let db = client.db('MyStore')

       let change_streams = db.collection('products').watch()
          change_streams.on('change', function(change){
            console.log(JSON.stringify(change));
          });
      });