MongoCDC

MongoCDC (Change Data Capture)

Configure MongoDB with replica set

To enable MongoDB with a replica set on your local instance, follow these steps:

1. Shutdown Existing MongoDB Instance:

   • Ensure that your existing MongoDB instance is not running. If it is, shut it down.

2. Modify mongod.conf File:

   • Open your MongoDB configuration file, usually located at /etc/mongod.conf.
   • Add or uncomment the following lines to configure replication:

       replication:
         replSetName: rs0
         oplogSizeMB: 1024
   

3. Start MongoDB Instance:

   • Restart your MongoDB instance to apply the configuration changes.

     sudo service mongod restart

4. Check MongoDB Status:

   • Verify the status of MongoDB and ensure there are no errors.

     sudo chown -R mongodb:mongodb /var/lib/mongodb
     sudo chown mongodb:mongodb /tmp/mongodb-27017.sock
     
     sudo service mongod restart
     

How to use MongoCDC

Integrate MongoCDC into your project to capture and react to MongoDB operations using Change Data Capture (CDC). Follow the code example below:

import MongoCDC from "./index";

const mongoCDC = new MongoCDC("mongodb://127.0.0.1:27017/local", { ns: "databaseName.*" });

// Start listening to oplogs
mongoCDC.listen();

// Event for all oprations
mongoCDC.on('op', (doc) => {
    console.log(JSON.stringify(doc, null, 2));
});

// Event for insert
mongoCDC.on('insert', (doc) => {
    console.log(JSON.stringify(doc, null, 2));
});

// Event for update
mongoCDC.on('update', (doc) => {
    console.log(JSON.stringify(doc, null, 2));
});

// Event for delete
mongoCDC.on('delete', (doc) => {
    console.log(JSON.stringify(doc, null, 2));
});


// Registering a Filter for a Specific Collection (databaseName.user)
mongoCDC.filter('databaseName.user').on('op', (doc) => {
    console.log("filter :: ",JSON.stringify(doc, null, 2));
});

Feel free to customize the ns args

For enable MongoCDC logs

• set DEBUG='cdc:*'