Mongoose Trying to open unclosed connection

Question

This is a simplified version of the problem, but basically I'm trying to open 2 mongodb connections with mongoose and it's giving me "Trying to open unclosed connection." error.

Code sample:

var db1 = require('mongoose');
db1.connect('my.db.ip.address', 'my-db');

var db2 = require('mongoose');
db2.connect('my.db.ip.address', 'my-db');

db2.connection.close();
db1.connection.close();

Any idea how to make it work?

@NilsH: use case: DB connections decided by config file using different sections for different environments (prod, staging, dev) to create loose coupling between the application and the environment it is running in. In dev all databases are on localhost so that it's easy to manage; in production databases are on separate machines with different replication settings, etc. — robbrit, Jun 12 '13 at 16:10

score 46 · Accepted Answer · answered Apr 07 '13 at 13:25

46

connect() opens the default connection to the db. Since you want two different connections, use createConnection().

API link: http://mongoosejs.com/docs/api.html#index_Mongoose-createConnection

answered Apr 07 '13 at 13:25

Raghuveer

1,737
20
27

This doesn't work on mongolab creating multiple connection for 2 database will result to `MongoError: database names cannot contain the character '.'` in mongolab – jofftiquez Feb 27 '16 at 08:04

score 2 · Answer 2 · answered Jul 19 '13 at 15:21

To add on Raghuveer answer :

I would also mention that instead of using mongoose directly (you are probably using it this way you end up on this post) :

require('mongoose').model(...);

You would use the returned connection :

var db = require('mongoose').connect('xxx', 'yyy');
db.model(...);

score 2 · Answer 3 · answered Dec 31 '16 at 12:30

2

I get this issue while running my tests.

This is what I did to solve it.

//- in my app.js file.
try {
    mongoose.connect('mongodb://localhost/userApi2'); //- starting a db connection
}catch(err) {
    mongoose.createConnection('mongodb://localhost/userApi2'); //- starting another db connection
}

answered Dec 31 '16 at 12:30

ArchNoob

3,946
5
32
59

2

I'm still using this method, and it works! Would like someone to comment what's wrong about it after downvote. – ArchNoob Feb 17 '17 at 06:27
I can attest that this actually works especially for testing – gbozee Apr 11 '17 at 23:09

score 2 · Answer 4 · answered May 24 '17 at 01:45

I had this problem doing unit test with mocha.

The problem came when I added a second test because beforeEach is called twice.

I've solved this with this code:

const mongoose = require('mongoose');
describe('Your test suite', () => {
    beforeEach( () => {
        if (mongoose.connection.db) {
            return; // or done();
        } else {
            // connect to mongodb
    });

    describe('GET /some-path', () => {
       it('It should...', () => {

       });
    });

    describe('POST /some-path', () => {
       it('It should...', () => {

       });
    });
});

Hope it helps you!

score 0 · Answer 5 · answered Jul 23 '16 at 11:44

You are attempting to open the default connection ( which is not yet closed ) a 2nd time.

do the following instead

var db = require('mongoose'); //note only one 'require' needed.
var connectionToDb1 = db.createConnection('my.db1.ip.address', 'my-db1');
var connectionToDb2 = db.createConnection('my.db2.ip.address', 'my-db2');

score 0 · Answer 6 · answered Feb 17 '17 at 15:42

Using mongoose.disconnect(fn):

mongoose.disconnect(() => {

  // here it would be possible "reset" models to fix 
  // OverwriteModelError errors
  mongoose.models = {};

  // here comes your logic like registering Hapi plugins
  server.register(somePlugin, callback);
});

I found this question typing the error message and despite my problem is a bit different I believe it could be useful for those using Hapi. More specifically Hapi + rest-hapi + mocha.

When running mocha with --watch option I was facing both: OverwriteModelError and Error: Trying to open unclosed connection errors.

score 0 · Answer 7 · answered May 26 '21 at 12:56

0

Simple Solution -

 Use mongoose.createConnection() instead of  mongoose.connect()
    
    Its occurs because of version issue

answered May 26 '21 at 12:56

Shashwat Gupta

5,071
41
33

Mongoose Trying to open unclosed connection

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