Traefik basic auth on path

I'm trying to password protect a specific path for an app, but it seems I am missing something and the traefik documentation is not helpful:

Paste from docker-compose:

traefik:

command:
  - "--log.level=INFO"
  - "--providers.docker=true"
  - "--providers.docker.exposedbydefault=false"
  - "--entrypoints.web.address=:80"
  - "--entrypoints.websecure.address=:443"
  - "--entrypoints.web.http.redirections.entryPoint.to=websecure"
  - "--entrypoints.web.http.redirections.entryPoint.scheme=https"
  - "--certificatesresolvers.letsencrypt.acme.httpchallenge=true"
  - "--certificatesresolvers.letsencrypt.acme.httpchallenge.entrypoint=web"
  - "--certificatesresolvers.letsencrypt.acme.email=email@email.com"
  - "--certificatesresolvers.letsencrypt.acme.storage=/etc/traefik/acme.json"

service:

labels:
  - "traefik.enable=true"
  - "traefik.http.routers.service.middlewares=service"
  - "traefik.http.routers.service.rule=Host(`domain.example.com`)"
  - "traefik.http.middlewares.service.headers.stsSeconds=31536000"
  - "traefik.http.middlewares.service.headers.forceSTSHeader=true"
  - "traefik.http.middlewares.service.headers.stsIncludeSubdomains=true"
  - "traefik.http.middlewares.service.headers.stsPreload=true"
  - "traefik.http.middlewares.service.headers.referrerPolicy=no-referrer"
  - "traefik.http.middlewares.service.headers.browserXssFilter=true"
  - "traefik.http.middlewares.service.headers.customRequestHeaders.X-Forwarded-Proto=https"
  - "traefik.http.routers.service.tls.certresolver=letsencrypt"

If I add the following labels basic auth is working but it's enabled on the whole website:

"traefik.http.middlewares.service-auth.basicauth.usersfile=/etc/traefik/auth"
"traefik.http.routers.service.middlewares=service,service-auth"

I played around with adding a second router like so, but that doesn't seem to work:

"traefik.http.routers.service-admin.rule=Host(domain.example.com) && PathPrefix(/somepath)"
"traefik.http.middlewares.service-auth.basicauth.usersfile=/etc/traefik/auth"
"traefik.http.routers.service-admin.middlewares=service-auth"

What am I missing?

Solution

I managed to figure it out with some "educated" guesses. It seems the order of the labels and the spacing between them plays a vital role. Adding a second router (without a service) was indeed the correct way of accomplishing this but separating the routers and middlewares code blocks was important:

  - "traefik.enable=true"

  - "traefik.http.routers.service.rule=Host(`example.example.com`)"
  - "traefik.http.routers.service-admin.rule=Host(`example.example.com`) && PathPrefix(`/somepath`)"
  - "traefik.http.routers.service.tls.certresolver=letsencrypt"
  - "traefik.http.routers.service-admin.tls.certresolver=letsencrypt"
  - "traefik.http.routers.service.middlewares=service"
  - "traefik.http.routers.service-admin.middlewares=service-admin"

  - "traefik.http.middlewares.service.headers.stsSeconds=31536000"
  - "traefik.http.middlewares.service.headers.forceSTSHeader=true"
  - "traefik.http.middlewares.service.headers.stsIncludeSubdomains=true"
  - "traefik.http.middlewares.service.headers.stsPreload=true"
  - "traefik.http.middlewares.service.headers.referrerPolicy=no-referrer"
  - "traefik.http.middlewares.service.headers.browserXssFilter=true"
  - "traefik.http.middlewares.service.headers.customRequestHeaders.X-Forwarded-Proto=https"
  - "traefik.http.middlewares.service-admin.basicauth.usersfile=/etc/traefik/auth"

Note: traefik version used is 2.2.1