Replica Set not working as expected

Question

I have configured like below and my MongoDB don't need username or password:

mongo: {
    module: 'sails-mongo',
    url: "mongodb://127.0.0.1:27017/mydb",
    replSet: {
        servers: [
            {
                host: "127.0.0.1",
                port : 27018
            },
            {
                host: "127.0.0.1",
                port : 27019
            }
        ],
        options: {connectWithNoPrimary:true, rs_name:"rs0"}
    }      
}

It's working fine, meaning I do not get a connection error and I am able to do querying. But when I brought down 127.0.0.1:27017, 127.0.0.1:27018 becomes PRIMARY as if I did a rs.status(). After this, I am no longer able to do any query and keep getting the following:

Error: no open connections

I am sure that I setup replica-set in my local machine correctly as I used MongoDB native driver to test the above mentioned scenario (bring down PRIMARY and SECONDARY take over as PRIMARY) and there is no problem.

var url = 'mongodb://127.0.0.1:27017,127.0.0.1:27018,127.0.0.1:27019/mydb?w=0&wtimeoutMS=5000&replicaSet=sg1&readPreference=secondary';

mongodb.MongoClient.connect(url, function(err, result) {
    if(err || result === undefined || result === null) {
          throw err;
    } else {
          db = result;  
    } 
});

Answer 1

ok I found the answer. This message emitted because of session.js. I commented everything in the file and now it is working. The reason I guess is in session.js, it only pointing to a single host, which is the original PRIMARY. when you bring down this mongodb PRIMARY, session.js no longer can connect so it threw exception. I also tried the mongodb URL string in sessions.js by putting in also the hosts ip in the replica set (mongodb://127.0.0.1:27017,127.0.0.1:27018,127.0.0.1:27019/mydb) but failed to "sails lift". When put only single host then it is fine.

now if I need to store sessions info, I need to start another mongodb instance then session.js point to this new instant.