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

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" #<-----

Answer 3

Thanks to #Keith I found the solution
version: '3'
services:
website:
build: ./website
expose: [3000]
networks: # It's essential to specify the same network in every service
- webgateway
labels:
- "traefik.http.routers.website.rule=Host(`localhost`)" # Use the right format
- "traefik.port=3000" # Let traefik find the right port
blog:
build: ./blog
expose: [4000]
networks:
- webgateway
labels:
- "traefik.http.routers.blog.rule=Host(`localhost`) && PathPrefix(`/blog`)" # blog has a root as `/blog` so no need to strip otherwise too many redirects
- "traefik.port=4000"
docs:
build: ./docs
expose: [3000]
networks:
- webgateway
labels:
- "traefik.http.routers.docs.rule=Host(`localhost`) && PathPrefix(`/docs`)"
- "traefik.http.routers.docs.middlewares=strip-docs" # Necessary as Keith mentioned
- "traefik.http.middlewares.strip-docs.stripprefix.prefixes=/docs"
- "traefik.port=3000"
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