Unable to reach service running behind traefik

Hi!

I apologize in advance if this question is out of scope for this discussion forum, but I'm hoping that someone here has expertise with both traefik + seq and is able to point me in the right direction :slight_smile:

I'm currently trying to set up a small ASP.NET Core web application using docker compose. I want to use Seq to capture the log output from the various services, unfortunately I'm unable to reach the Seq UI. I'm suspecting that maybe certain env variables ( SEQ_API_LISTENURIS ? SEQ_API_CANONICALURI ?) have to be set for my setup to work, but I haven't been able to find the right combination.

Minimal reproduction

services:
  traefik:
    image: traefik:2.6
    container_name: traefik
    restart: unless-stopped
    command:
      - "--providers.docker=true"
      - "--api.dashboard=true"
      - "--log.level=DEBUG"
      - "--api.debug=true"
      - "--entrypoints.web.address=:80"
    ports:
      - 80:80
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock:ro
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.traefik.entrypoints=web"
      - "traefik.http.routers.traefik.service=api@internal"
      - 'traefik.http.routers.traefik.middlewares=strip'
      - 'traefik.http.middlewares.strip.stripprefix.prefixes=/traefik'
      # Dashboard
      - "traefik.http.routers.dashboard.rule=Host(`localhost`) && (PathPrefix(`/api`) || PathPrefix(`/dashboard`))"
      - "traefik.http.routers.dashboard.service=api@internal"
      - "traefik.http.routers.dashboard.middlewares=auth"

  whoami:
    image: traefik/whoami
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.whoami.rule=Host(`localhost`) && PathPrefix(`/whoami`)"
      - "traefik.http.routers.whoami.entrypoints=web"
      - "traefik.http.services.whoami.loadbalancer.server.port=80"
    
  seq:
    image: datalust/seq:latest
    restart: unless-stopped 
    environment:
      ACCEPT_EULA: "Y"
      SEQ_DIAGNOSTICS_INTERNALLOGGINGLEVEL: "Debug"
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.seq.rule=Host(`localhost`) && PathPrefix(`/seq`)"
      - "traefik.http.routers.seq.entrypoints=web"
      - "traefik.http.services.seq.loadbalancer.server.port=80"
    volumes:
      - ./seq_data:/data
    ports:
      - "5341:5341"
      - "8084:80"

After starting the services with docker compose up, the whoami service is reachable via localhost/whoami - but the seq web is NOT reachable via localhost/seq, the browser reports an 404 in the browser devtools. I can confirm that the service is running because it is reachable via the local port binding localhost:8084.

Does anybody have an idea what I could try next?

Thanks!

If somebody is interested, I also posted this question to the seq discussion forum: Docker compose: Unable to reach seq running behind traefik · Discussion #1446 · datalust/seq-tickets · GitHub

The author of the service kindly helped me to identify the issue.