mongo-oplog

Watch mongodb oplog in a simple way

Mongo Oplog

Listening to MongoDB live changes using oplog.

$ npm install mongo-oplog
var MongoOplog = require('mongo-oplog');
var oplog = MongoOplog('mongodb://127.0.0.1:27017/local', 'test.posts').tail();
 
oplog.on('op', function (data) {
  console.log(data);
});
 
oplog.on('insert', function (doc) {
  console.log(doc.op);
});
 
oplog.on('update', function (doc) {
  console.log(doc.op);
});
 
oplog.on('delete', function (doc) {
  console.log(doc.op._id);
});
 
oplog.on('error', function (error) {
  console.log(error);
});
 
oplog.on('end', function () {
  console.log('Stream ended');
});
 
oplog.stop(function () {
  console.log('server stopped');
});
  • uri: Valid MongoDB uri or a MongoDB server instance.
  • ns: Namespace for emitting, namespace format is database + . + collection eg.(test.posts).
  • options MongoDB onnection options.

Start tailing.

oplog.tail(function(){
  console.log('tailing started');
})

Stop tailing and disconnect from server.

oplog.stop(function(){
  console.log('tailing stopped');
})

Filter by namespace.

oplog.filter('*.posts')
oplog.tail();

Filter by namespace.

oplog.filter()
.ns('*.posts')
.on('op', function(doc){
  console.log(doc);
});
 
// or 
oplog.filter()
.ns('test.*')
.on('op', function(doc){
  console.log(doc);
});
 
// or 
oplog.filter()
.ns('test.posts');
.on('op', function(doc){
  console.log(doc);
});
 
// start tailing 
oplog.tail();

Events supported by oplog and filter;

  • op: All bellow operations (oplog/filter).
  • insert: Document insert (oplog/filter).
  • update: Document update (oplog/filter).
  • delete: Document delete (oplog/filter).
  • end: Cursor stream ended (oplog).
  • error: Error (oplog).

Configure MongoDB for ac active oplog:

Start MongoDB with:

$ mongod --replSet test

Start a mongo shell and configure mongo as follows:

> var config = {_id: "test", members: [{_id: 0, host: "127.0.0.1:27017"}]}
> rs.initiate(config)

Once configuration is initiated then you can run the test:

$ npm install
$ make test

(The MIT License)

Copyright (c) 2013 Jonathan Brumley <cayasso@gmail.com>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.