Can't connect to container using network_mode: "service:gluetun"

[chrisbanes]

Describe the bug

I use multiple Docker Compose files. In the first is tsdproxy using a network called tailscale.

services:
  tsdproxy:
    image: almeidapaulopt/tsdproxy:latest
    container_name: tsdproxy
    networks:
      - tailscale
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - /foo:/data
      - /bar:/config
    restart: unless-stopped
    ports:
      - "8080:8080"

networks:
  tailscale:
    external: true

In the second I use gluetun, to allow services to connect outwards over a VPN:

services:
  vpn:
    image: qmcgaw/gluetun
    container_name: vpn
    cap_add:
      - NET_ADMIN
    networks:
      vpn:
      tailscale:
    sysctls:
      - net.ipv4.ip_forward=1
      - net.ipv6.conf.all.forwarding=1
    restart: unless-stopped
    devices:
      - /dev/net/tun:/dev/net/tun
    ports:
      - 9696:9696 # prowlarr
    volumes:
      - /foo:/gluetun

  prowlarr:
    container_name: prowlarr
    image: lscr.io/linuxserver/prowlarr:latest
    network_mode: "service:vpn"
    labels:
      tsdproxy.enable: "true"
      tsdproxy.name: "prowlarr"
      tsdproxy.container_port: 9696

networks:
  tailscale:
    external: true

Unfortunately I'm not able to connect to the any of the containers using network_mode: "service:vpn". Using a Tailscale sidecar has been working fine for me previously.

Send config
The tsdproxy.yaml is very basic:

defaultproxyprovider: default
docker:
  local:
    host: unix:///var/run/docker.sock
tailscale:
  providers:
    default:
      authKey: "foo"
  datadir: /data/
http:
  hostname: 0.0.0.0
  port: 8080
log:
  level: trace
  json: false
proxyaccesslog: true

Logs

On tsdproxy startup:

9:49AM DBG trying to connect to internal port container=/deluge docker=local hostname=172.31.0.1 module=proxymanager port=58946
9:49AM DBG Error connecting to internal port error="no valid target found for internal ports " container=/prowlarr docker=local module=proxymanager
9:49AM DBG trying to connect to internal port container=/prowlarr docker=local hostname=172.31.0.1 module=proxymanager port=9696

When trying to connect:

9:50AM ERR error host=prowlarr.foo-bar.ts.net method=GET module=proxymanager proxyname=prowlarr status=502 url=/

[MadManMcIvor]

Having this same issue as well! Sadly nothing to add, just wanted to follow the issue.