How to omit the port number when running a Node.js Docker container

Theo Itzaris 0
Viewed 23

I have a simple Node.js server application which I have containerized.

The Node.js server runs on port 3000 so it answers at URL http://localhost:3000.

In another application I have a docker-compose.yml file which pull the Node.js app image and run it, like this:

version: '3'

services:
  myserver:
    container_name: myserver_nodejs
    image: registry.gitlab.com/cs-repos/work/myserver:v1.0.2-latest
    ports:
      - 3000:3000

It pulls the image from GitLab container registry, locally, and runs the container.

Issue:

In order to make a request to the server I need to add the port number like this: localhost:3000, then the path.

I wonder, is there a way so that the docker-compose.yml handles the port for me, so that I don't have to use it in my requests?

So to make a request like this: http://localhost/sales, and internally the request goes to port 3000.

Also i added a record in the /etc/hosts:

  • 127.0.0.1 my.server.com.

Instead of using the localhost, I can use the mapped address my.server.com but I need the port number at the end as well.

The ports property just makes a mapping between the host and the container, it is needed but it's not solving the issue:

 ports:
     - 3000:3000
url http docker-compose docker
1 Answers

Albeit the question is phrased in terms of docker-compose.yml, the standard answer actually has not much to do with Docker:

HTTP → 80

If you're relying on the HTTP protocol, which has 80 as default port, you will be able to connect to the server with a "port-free" URL if it listens to port 80.

Then, in terms of Docker Compose, one could write:

ports:
  - "80:3030"

then browsing http://localhost should work.

HTTPS → 443

If you're relying on HTTPS / TLS, which has 443 as default port, you will be able to connect to the server with a "port-free" URL if it listens to port 443.

So, one could write:

ports:
  - "443:3030"

then browsing https://localhost should work (assuming the container can serve resources in HTTPS).

Remark on HTTPS

Note that if your Docker Compose service is not TLS-aware, a typical solution amounts to completely removing the ports: invocation for that service, make it serve in HTTP, and put in front of this service a (dockerized) TLS termination proxy.

For more details on this architecture, see e.g. these two older answers of mine:

ErikMD0
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