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.\

Answer 1

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!

Answer 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
}

Answer 3

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.

Answer 4

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

Answer 5

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(...);

Answer 6

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');