How to map specific port inside docker container when using traefik?

Question

Here's my docker-compose.yml:

version: '3'
services:
  website:
    build: ./website
    expose: [3000]
    labels:
      - "traefik.frontend.rule=Host:localhost"
  blog:
    build: ./blog
    expose: [4000]
    labels:
      - "traefik.frontend.rule=Host:localhost;PathPrefix:/blog"
  docs:
    build: ./docs
    expose: [3000]
    labels:
      - "traefik.frontend.rule=Host:localhost;PathPrefix:/docs"
  proxy:
    image: traefik
    command: --api.insecure=true --providers.docker
    networks:
      - webgateway
    ports:
      - "80:80"
      - "8080:8080"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock

networks:
  webgateway:
    driver: bridge

What I want is access three different node.js websites via different routes. But these three node.js websites actually expose different ports. Now my treafik is running. I can config via localhost:8080 But localhost localhost/blog and localhost/docs are all 404 page not found

P.S: I'm not sure whether port is the issue I should investigate, because changing one node.js service to port 80 doesn't solve the puzzle. And I saw on traefik dashboard the rule is Host(blog-dev)

Answer 1

PathPrefix:/blog

When you have this as a routing rule, traefix won't automatically remove the prefix when sending to the container.

So unless you have a route /blog inside your container you will get a 404.

So what you normally do is also add a middleware to strip this -> https://docs.traefik.io/middlewares/stripprefix/

Also you appear not to be setting your rules based on your service.

So as an example for your first service blog,

try->

labels:
    - "traefik.http.routers.blog.rule=Host(`localhost`) && PathPrefix(`/blog`)"
    - "traefik.http.routers.blog.middlewares=strip-blog"
    - "traefik.http.middlewares.strip-blog.stripprefix.prefixes=/blog"

And then do the same for your other routes, don't forget to replace routers.blog with routers.docs etc..

Answer 2

labels: 
- traefik.http.services.<YOUR-SERVICE-NAME>.loadbalancer.server.port=9763

EG:

services:
  wso:
    image: "my-custom-wso-image"
    volumes:
      - .....
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.wso.tls=true"
      - "traefik.http.routers.wso.rule=Host(`my.nice.url`)"
      - "traefik.http.services.wso.loadbalancer.server.port=9763" #<-----