Datadog custom metrics from app (docker container) inside host

Question

I have a datadog agent in my host machine, CentOS. I have a nodeJS application, where I want to send custom metrics from it.

Config from app:

var StatsD = require('hot-shots');
var dogstatsd = new StatsD({
    port: 8125,
    globalTags: { env: process.env.NODE_ENV },
    errorHandler: function (error) {
        console.log("Socket errors caught here: ", error);
    }
});

module.exports = dogstatsd;

Not sure what I'm doing wrong, but no custom metrics are sent. How I can make my app (inside docker) able to use the host dogstatsd UDP server to send packets to datadog?