Docker not expose ports for node and webpack dev-server

Question

I have MacOS High Sierra and my goal is to run node web-applications without installation node on macos (I wanna use docker to do it). That web-application is usually angular-webpack (compilation + run dev serwer).

Dockerfile:

FROM node
WORKDIR /work
CMD while true; do sleep 10000; done
EXPOSE 3002

The line CMD while ... makes that container will be not killed by docker after run it - this allow us to "login" into container (by docker exec -it...).

Bash script run.cmd which run container:

set -e
docker build -t node-cmd .
docker rm -f node-cmd |:
docker run -d --name node-cmd -p 3002:3002 -v /Volumes/work:/work node-cmd
docker exec -it node-cmd /bin/bash

Where /Volumes/work is directory on my MacOs which contains angular projects.

Here is example application in file /work/tmp/example.js (mapped in container) for which problem is visible (however them main goal is to find proper configuration of webpack dev-server):

var http = require('http');

http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    res.end('Hello World\n'+new Date);
}).listen(3002, '127.0.0.1');

console.log('Server running at http://127.0.0.1:3002/');

So first I run run.cmd - here is what docker ps write:

CONTAINER ID        IMAGE               COMMAND                   CREATED             STATUS              PORTS                    NAMES
e22188d8e136        node-cmd            "/bin/sh -c 'echo \"R…"   16 seconds ago      Up 15 seconds       0.0.0.0:3002->3002/tcp   node-cmd

Inside container I type commands:

root@5cd3773e7815:/work# cd tmp
root@5cd3773e7815:/work# node example.js & 
[1] 18
root@5cd3773e7815:/work/tmp# Server running at http://127.0.0.1:3002/

So serwer was start. Now I test:

root@5cd3773e7815:/work/tmp# curl 127.0.0.1:3002
Hello World

So inside docker everything works fine. Now when I go to my macos Chrome browser http://127.0.0.1:3002 i get

This page isn’t working 127.0.0.1 didn’t send any data.

ERR_EMPTY_RESPONSE

If I remove -p 3002:3002 from run.cmd file the browser response change to

127.0.0.1 refused to connect. Try: Checking the connection Checking the proxy and the firewall

ERR_CONNECTION_REFUSED

I also try tu use docker run --ip=127.0.0.1... but I get message that

docker: Error response from daemon: user specified IP address is supported on user defined networks only.

When i try to use docker run --net=host ... it doesn't change anything

I alswo wanna mention that when I run mysql image by docker run -p 3306:3306 ... I works properly (!) - so may be the problem is with node image (?)

Questions:

1. How to "unblock" port 3002 in container to allow host browser to connect with service inside container?
2. How to use subdomains like subdomain.local:3002 too?
3. How to use subdomains using webpack devServer (used in angular) instead above example.js (i need to have run many angular web-application each on different port with individual subdomain) ?

Answer 1

I think this issue might be related to the fact that you are specifying 127.0.0.1 as host. Try to use 0.0.0.0 instead:

var http = require('http');

http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    res.end('Hello World\n'+new Date);
}).listen(3002, '0.0.0.0');

For subdomains you will most likely have to edit the /etc/hosts file on your local machine.

Answer 2

Rob Helps me to find main part solution of problem. I make tests and investigation and find out that when we set .listen(3002, '0.0.0.0') and edit /etc/hosts by add line like

127.0.0.1 node-test.local

And when we type in browser node-test.local:3002 it will works. However if we use webpack dev starter, in browser we get error:

Invalid Host header

So we need reconfugre webpack.js file (e.g. in angular-starter framework (ASF) it is in ./config/webpack.dev.js) by adding disableHostCheck: true - here is egzample of configuration:

devServer: {
  port: "3002",            // in ASF is METADATA.port,
  host: "0.0.0.0",         // in ASF is METADATA.host,     
  public: "0.0.0.0:3002",  // in ASF is METADATA.public,
  disableHostCheck: true,
  //...
}

After that http://node-test.local:3002 should works on MacOs Browsers.

If we need to have many subdomains on one port number (which is out of frame of this question) then probably we must use reverse-proxy (which is probably standard solution for docker multi-webapps(subdomains) over port 80)