How to bind docker container ports to the host using helm charts

Question

I am writing a simple docker file for a golang and I'm still getting familiar with docker so I know what I want to do just don't know how to do it:

What I have right now (below) is exposing port 8080, but I want to expose port 80 but forward that to port 8080.

I know that I can do it via docker run -p but I'm wondering if there's a way I can set it up in Dockerfile or something else. I'm trying to find how I can do that through Helm.

Dockerfile:

FROM scratch

COPY auth-service /auth-service

EXPOSE 8080

CMD ["/auth-service","-logtostderr=true", "-v=-1"]

Answer 1

EXPOSE informs Docker that the container listens on the specified network ports at runtime but does not actually make ports accessible. only -p as you already mentioned will do that:

docker run -p :$HOSTPORT:$CONTAINERPORT

Or you can opt for a docker-compose file, extra file but also do the thing for you:

version: "2"
services:
  my_service:
    build: .
    name: my_container_name
    ports:
      - 80:8080
    .....

Edit:

If you are using helm you have just to use the exposed docker port as your targetPort :

apiVersion: v1
kind: Service
metadata:
  name: {{ template "fullname" . }}
  labels:
    chart: "{{ .Chart.Name }}-{{ .Chart.Version | replace "+" "_" }}"
spec:
  type: {{ .Values.service.type }}
  ports:
  - port: {{ .Values.service.externalPort }}
    targetPort: {{ .Values.service.internalPort }} #8080
    protocol: TCP
    name: {{ .Values.service.name }}
  selector:
    app: {{ template "fullname" . }}