How to pass a Proton VPN port forward from Gluetun to Transmission (via LinuxServer.io)

[hozza]

Can anyone help? I'm looking for someone more savvy with this sort of inter-container config setup or maybe someone has done something similar already.

Once gluetun has got a forwarded port from Proton VPN, it's saved into the /tmp/gluetun/forwarded_port file.

How could docker-compose read the content of this file, after it's written, and then pass it along to the Transmission container as an environment variable (PEERPORT=) or config modification.

I'm thinking volume mount /tmp/gluetun/forwarded_port to the host, then delay starting transmission starting by using depends on with a health check (?) then using another container (maybe alpine?) to run a bash/sh script to copy the content from the file and provide as an environment variable to linuxserver.io's transmission container as the env var PEERPORT.

It's also mentioned in issue 53 (specifically this comment) to use sed to modify transmissions settings.json with the port directly but this would require transmission to be restarted maybe? I also spotted somewhere that linuxserver.io images allow you to run scripts at boot.

Example compose.yml...

version: "3"

services:
  gluetun:
    container_name: gluetun
    restart: unless-stopped
    image: docker.io/qmcgaw/gluetun
    ports:
      # Built-in VPN HTTP Control Server
      # - 127.0.0.1:8000:8000
      # Transmission WebUI
      - 127.0.0.1:9091:9091
    cap_add:
      - NET_ADMIN
    devices:
      - /dev/net/tun:/dev/net/tun
    environment:
      - PUID=1000
      - PGID=1000
      - BLOCK_SURVEILLANCE=on
      - UPDATER_PERIOD=24h
    env_file: 
      - gluetun.env
      # - VPN_SERVICE_PROVIDER=protonvpn # or other port forwarding vpn provider
      # - OPENVPN_USER= # (append `+f2+pmp`)
      # - OPENVPN_PASSWORD=
      # - SERVER_COUNTRIES=
      # - VPN_PORT_FORWARDING=on

  transmission:
    container_name: transmission
    restart: unless-stopped
    network_mode: "service:gluetun"
    image: lscr.io/linuxserver/transmission
    volumes:
      - /media/containers/transmission:/config
      - /media/downloads:/downloads
      - /media/downloads/watch:/watch
    environment:
      - PGID=1000
      - PUID=1000
      - DOCKER_MODS=linuxserver/mods:transmission-floodui
    env_file:
      - transmission.env
      # - USER=
      # - PASS=
      # - PEERPORT= # get this from gluetun somehow?

Opening a port would make downloading slightly faster with more peers. e.g. linux iso's and other such legit content...

[Michsior14]

You can use my docker mod for transmission that will handle port updating automatically.

In your example it's as easy as adjusting DOCKER_MODS in the following way:

DOCKER_MODS=michaukrieg/docker-mods:transmission-gluetun-port-update|linuxserver/mods:transmission-floodui

[DennisGaida]

How do you deal with port forwarding on the gluetun docker container itself? Or do you use host network not bridged?

[Michsior14]

I've never had the need to expose a forwarded port on gluetun container. I do nothing else than this.

[socketbox]

There are also these solutions:

• https://gist.github.com/fizzxed/958d8cdfa4dad8a97651afce4d74efce
• https://codeberg.org/TechnoSam/qbittorrent-gluetun-port-update
• https://github.com/AlbyGNinja/port-sync