API Call from backend to backend fail

Traefik Traefik v2
1

Hi,

First, thank you just for reading this and trying to help us.

We are migrating from v1 to v2 and have some issues on API calls from back to back.
We used to have 2 networks (front and back), and our backend used to communicate via back network using aliases.

With v2, we struggle to understand how to do it.

The context :

  • VueJs Front that calls our php API (works well)
  • VueJs Front calls php WS (works well)
  • php WS that calls php API (doesn't work)

Here are the interesting sample of our docker-compose files

Traefik

version: "3"

services:
  traefik:
    env_file: ./.env
    container_name: app-traefik
    image: ${TRAEFIK_IMAGE}
    command:
      - "--log.level=DEBUG"
      - "--api.insecure=true"
      - "--providers.docker=true"
      - "--providers.docker.exposedbydefault=false"
      - "--entrypoints.web.address=:80"
    ports:
      - 8181:8080
      - 80:80
      - 443:443
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock:ro
    networks:
      - "proxy"

networks:
  proxy:

WS

version: "3"

services:
  php:
    env_file: ./.env
    image: app/ws/php
    container_name: app-ws-php
    build: ./.docker/ws/local
    volumes:
      - ./:/var/www
    labels:
      traefik.enable: true

      traefik.http.routers.websocket.rule: Host(`ws.${URL}`)
      traefik.http.routers.websocket.entrypoints: web
      traefik.http.routers.websocket.service: websocket

      traefik.http.services.websocket.loadbalancer.server.port: ws.${URL}
      traefik.http.services.websocket.loadbalancer.server.port: 8080
      providers.docker.network: proxy
    networks:
      - proxy

networks:
  proxy:
    external:
      name: "traefik_proxy"

API

version: "3"

services:
  nginx:
    env_file: ./.env
    image: app/api/nginx
    container_name: app-api-nginx
    build: ./.docker/nginx/local
    volumes:
      - ./:/var/www
    labels:
      traefik.enable: true

      traefik.http.routers.api.rule: Host(`api.${URL}`)
      traefik.http.routers.api.entrypoints: web
      traefik.http.routers.api.service: api

      traefik.http.services.api.loadbalancer.server.url: api.${URL}
      traefik.http.services.api.loadbalancer.server.port: 80
      providers.docker.network: proxy
    environment:
      NGINX_PORT: 80
    depends_on:
      - php
      - db
    networks:
      - proxy

  php:
    env_file: ./.env
    image: app/api/php
    container_name: app-api-php
    build: ./.docker/php/local
    volumes:
      - ./:/var/www
    depends_on:
      - db
    labels:
      traefik.enable: false
    networks:
      - proxy

  db:
    env_file: ./.env
    image: mysql:8.0.19
    container_name: app-api-db
    environment:
      - MYSQL_DATABASE=app
      - MYSQL_ROOT_PASSWORD=root
      - MYSQL_USER=app
      - MYSQL_PASSWORD=app
    volumes:
      - app-api-db:/var/lib/mysql:cached
    ports:
      - 3311:3306
    networks:
      - proxy

volumes:
  app-api-db:

networks:
  proxy:
    external:
      name: "traefik_proxy"

Here is our WS logs when trying to call API :

cURL error 6: Could not resolve host: api.dev.app.com

It works well if I use the container_name since they are on the same network (proxy), but I can't find how to set a backend URL (from back to back).
If anyone can enlight me.

Thanks in advance to anyone who have read that :slight_smile:
Have a nice day,