Attaching to iex and phoenix in a container?

[mvkvc]

Hello,

I am running a phoenix app with docker compose and I would like to connect to it in livebook when I set the command to be: iex --sname test --cookie mycookie -S mix phx.server. However it is unclear what I should put for the node in this case of it is possible. Any help would be appreciated.

Thank you!

[josevalim]

Hi @mvkvc! If Livebook and the Phoenix server is running on two different nodes: one outside and another inside Docker, then you need to start Livebook with the LIVEBOOK_DISTRIBUTION=name flag and use --name in your Phoenix app too. When connecting, you need to pass the name with the hosts. Similar to the ideas here: https://fly.io/docs/elixir/advanced-guides/connect-livebook-to-your-app/

[mvkvc]

Hi Jose, thank you for your answer. I will try this and then update this if I can get it working.

[gtaranti]

Hey, did you manage to make it work?
I'm still trying to do this.
I've followed the fly.io tutorial for connecting Livebook to an app in production with success, but connecting to a dockerized phoenix app on a remote host is still not working for me.

[matheuscamarques]

I'm using this docker compose file but not working

version: '3.8'  # Use the desired version of Docker Compose

services:
  postgresql:
    image: 'bitnami/postgresql:10'
    ports:
      - 5432:5432
    environment:
      - POSTGRESQL_USERNAME=postgres
      - POSTGRESQL_PASSWORD=postgres
      - POSTGRESQL_DATABASE=hive_dev
    volumes:
      - 'postgresql_data:/bitnami/postgresql'
    networks:
      - hive_livebook_network  # Use the custom network
      - hive_default

  meilisearch:
    image: getmeili/meilisearch
    command: ./meilisearch
    ports:
      - 7700:7700

  livebook:
    image: ghcr.io/livebook-dev/livebook
    ports:
      - "8080:8080"
      - "8081:8081"
    volumes:
      - ".:/livebook_data"
    environment:
      - ERL_AFLAGS="-proto_dist inet6_tcp"
    restart: always
    networks:
      - hive_livebook_network  # Use the custom network
      - hive_default

  hive:
    build: .
    # map the port of phoenix to the local dev port
    ports:
      - "4000:4000"
    environment:
      - HIVE_REPO_DATABASE_URL=postgres://postgres:postgres@postgresql:5432/hive_dev
    depends_on:
      - livebook  # Now hive depends on livebook
      - postgresql
      - meilisearch
    # mount the code folder inside the running container for easy development
    volumes:
      - .:/app
    networks:
      - hive_livebook_network  # Use the custom network
      - hive_default

volumes:
  postgresql_data:
    driver: local
networks:
  hive_livebook_network:
    driver: bridge  # Use 'bridge' as the driver for the custom network
  hive_default:
    driver: bridge

[jonatanklosko]

Looks like if both Livebook and the app runs via docker-compose, it's actually possible with short names distribution, that's the minimal config that works for me:

version: "3.8"

services:
  livebook:
    image: ghcr.io/livebook-dev/livebook
    ports:
      - "8080:8080"
      - "8081:8081"
    environment:
      - RELEASE_NODE=livebook@livebook

  app:
    # Any Elixir release app
    image: ghcr.io/livebook-dev/livebook
    environment:
      - RELEASE_NODE=app@app
      - RELEASE_COOKIE=verylongpass

Then in a Livebook session you can connect to the app with:

Node.set_cookie(:app@app, :verylongpass)
Node.connect(:app@app)

---

Here's a version using long names distribution. Note that we need to know the proper IP, I used what seems to be the default for the default network, perhaps we could determine it dynamically in env.sh.exs of the release app:

version: "3.8"

services:
  livebook:
    image: ghcr.io/livebook-dev/livebook
    ports:
      - "8080:8080"
      - "8081:8081"
    environment:
      - LIVEBOOK_DISTRIBUTION=name
      - RELEASE_NODE=livebook@127.0.0.1

  app:
    image: ghcr.io/livebook-dev/livebook
    environment:
      - LIVEBOOK_DISTRIBUTION=name
      - RELEASE_NODE=app@172.20.0.2
      - RELEASE_COOKIE=verylongpass

Then in Livebook:

Node.set_cookie(:"app@172.20.0.2", :verylongpass)
Node.connect(:"app@172.20.0.2")