在运行带端口转发的容器时，没有从node.js代码获取docker容器的IP地址

Question

I write a basic node.js code to get the IP of the Host. code looks like this:

var express = require('express');
var os = require('os');
var app = express();
var interfaces = os.networkInterfaces();


app.get('/',function(req,res){
var addresses = [];
for (var k in interfaces) {
    for (var k2 in interfaces[k]) {
        var address = interfaces[k][k2];
        if (address.family === 'IPv4' && !address.internal) {
            addresses.push(address.address);
        }
    }
}
  res.send("IP address of container  :  " + addresses);
});

app.listen(3000);

When I run this code on my local machine I will the correct IP

But when I containerize my application using Docker file :

FROM centos:7

MAINTAINER Vaibhav Jain <vaibhavjain882@gmail.com>

RUN yum -y install curl

RUN curl --silent --location https://rpm.nodesource.com/setup_4.x | bash -

RUN yum -y install nodejs

RUN mkdir "/ecsTest"
WORKDIR /ecsTest

ADD node_modules node_modules
ADD app.js package.json ./

CMD ["node","app.js"]

and run the container with port forwarding I am not getting the IP

command used for running the container:

docker run -d -p 3000:3000 image_name

appreciate the any lead. Thanks

Answer 1

Finally I find the solution for that. I tried IP npm module and use its function address() and it works fine for me.

Answer 2

You need to expose port 3000 in your Dockerfile:

EXPOSE  3000
CMD ["node","app.js"]