add error event for server???

[stableShip]

using mosca-v1.2.0, when I start a mosca server with mongodb as persistence,rabbitmq as backend, my mongodb did not start , I started my mosca server , it did't show any error and the ready message. I try to listen "error" event, nothing log.How can I get the error when I start the server??

server.on('error', function(err){
    console.log(err);
});

server.on('ready', function(){
    console.log('Mosca server is up and running');
});

my settting:

var pubsubsettings = {
    type: 'amqp',
    json: false,
    amqp: require('amqp'),
    exchange: 'ascolatore5672'
};

var moscaSettings = {
    port: 1883,
    backend: pubsubsettings,
    persistence: {
        factory: mosca.persistence.Mongo,
        url: "mongodb://localhost:27017/mosca"
    }
};

[mcollina]

I'm sorry but I don't understand what your issue is.

[stableShip]

when my persistence config seted, but it can not connect to the mongodb.I hope the server will show me the connnect error message ，but there is nothing show

[mcollina]

You are right, currently Mosca is swallowing the error at startup, a callback when this async.series completes is missing.

Would you like to send a PR?

[stableShip]

I will try , this is my first time to make a PR to a project like this, please don't bet on me, but I will try my best.