CODEWITHSUNDEEP
dockerdocker-compose
BU0
BU0

Reputation: 762

Docker network error connecting containers

I am having trouble wrapping my head around how to configure what I consider to be a pretty basic network setup in Docker.

Containers:

I've got the Wordpress & MariaDB containers up and running and chatting with eachother, but for some reason my Node.js container is unable to perform a basic HTTP call out to the Wordpress server. I immediately receive an Error: connect ECONNREFUSED 192.168.128.4:3000 error from my Node script.

I am running Docker Desktop Community on Mac OS v2.3.0.3.

My docker-compose.yml file looks like this:

services:

  db:
    image: mariadb:10.5.4-focal
    container_name: db
    volumes:
      - ./cms/conf/mysql/data:/var/lib/mysql
      - ./cms/sql:/docker-entrypoint-initdb.d
    environment:
      - MYSQL_ROOT_PASSWORD=******
      - MYSQL_USER=******
      - MYSQL_PASSWORD=******
      - MYSQL_DATABASE=wordpress
    restart: always

  cms.mysite.local:
    container_name: cms.mysite.local
    build:
      context: ./cms
    image: mysite/cms:5.4.2
    ports:
      - '3000:80'
    volumes:
      - ./cms/conf/php/uploads.ini:/usr/local/etc/php/conf.d/uploads.ini
      - ./cms/conf/nginx:/etc/nginx/conf.d
      - ./cms/logs/nginx:/var/log/nginx
      - ./cms/app/public:/var/www/html
    environment:
      - WORDPRESS_DB_NAME=wordpress
      - WORDPRESS_TABLE_PREFIX=wp_
      - WORDPRESS_DB_HOST=db
      - WORDPRESS_DB_USER=root
      - WORDPRESS_DB_PASSWORD=password
    depends_on:
      - db
    restart: always

  node:
    container_name: node
    build:
      context: ./www
    image: mysite/gatsby:2.23.12
    user: 'node'
    working_dir: /home/node/www
    volumes:
      - ./www:/home/node/www
      - /home/node/www/node_modules
    ports:
      - '8000:8000'
    depends_on:
      - cms.mysite.local
    restart: "always"

The cms.mysite.local container has an open port specified at 3000. I modified my local Mac OS machine's /etc/hosts file to add a 127.0.0.1 cms.mysite.local entry, and I am able to hit the Wordpress site in my browser and get a valid response. So it looks like everything is working there.

Then I have the following script set up in the node container:

const axios = require('axios')
const url = 'http://cms.mysite.local:80'
console.log('URL=' + url)
axios.get(url).then( (response) => {
  console.log('response=' + JSON.stringify(response.data))
})
.catch(function (error) {
  console.log('error=' + error)
})

I have this script set up to execute when the container starts. Everytime it runs, I get the error: Error: connect ECONNREFUSED 192.168.128.4:3000. Sure enough, when I try to access 192.168.128.4:3000 manually in my MacOS browser, I do indeed get no connection.

Why is the Node.js script trying to access http://192.168.128.4:3000 instead of my written http://cms.mysite.local:3000/ URL?

How can I force it to use the URL that maps correctly to the Wordpress docker container? Or how can I set up my URL so that my node container can make HTTP calls to my cms.mysite.local container?

[Edit #1] I have also tried updating my Node.js script to call out to http://cms.mysite.local:80/. I added some logging to make the output a little more clear.

> node ./test.js
URL=http://cms.mysite.local:80
error=Error: connect ECONNREFUSED 192.168.128.4:80

[Edit 2: Urg. I did not appropriately stop & rebuild my docker image for edit. I do see the appropriate ports being used after restarting. #1]

[Solve: Thanks to Fernando and Shizzen83 for the port callout!] Here's what was happening. I had my Wordpress site configured for port 3000 so that I could access it on that port through the browser. But I had a nginx config serving the site on port 80 inside of Docker. So Wordpress was issuing 301 redirects on port 80 requests to port 3000 because the internal Docker port didn't match the external Wordpress port. I switched out nginx to listen on port 3000 directly, and updated my docker-compose file to map 3000:3000 instead of 3000:80. And now things all line up. Thanks all!

Upvotes: 1

Views: 4282

Answers (2)

Shizzen83
Shizzen83

Reputation: 3529

Your mistake comes from the port used by Node to reach Wordpress. When you set 3000:80 in ports section of a container, it means nothing more than a query sent onto host on port 3000 will be redirected to internal port 80 of Wordpress container. Though your Node container is not the host, so you have to directly reach port 80 instead.

Upvotes: 1

Fernando Mani
Fernando Mani

Reputation: 134

Seems to be the port of cms.mysite.local you are exposing

ports:
  - 3000:80

which means that this container is mapped to port 3000 to outside (your host) but inside the docker network the container still have the 80 for incoming connections.

For your node container must be something like

axios.get('http://cms.mysite.local:80').then( (response) => {
  console.log('response=' + response.data)
})
.catch(function (error) {
 // handle error
console.log('error=' + error);
})

And node shows you the IP beacause he is resolving the DNS of your wordpress container inside the docker network

Upvotes: 3

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