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phpdockerphpstormxdebug

PhpStorm multi-docker hostname resolution

I have a fully set up docker environment furnished with Xdebug, properly set up with PhpStorm. My environment has multiple containers running for different functions. All appears to work great. CLI/Web interaction both stop at breakpoints as they should, no problems. However ...

I have a code snippet as follows:

// test.php
$host = gethostbyname('db'); //'db' is the name of the other docker box, created with docker-compose
echo $host;

If I run this through bash in the 'web' docker instance:

php test.php
172.21.0.2

If I run it through the browser:

172.21.0.2

If I run it via the PhpStorm run/debug button (Shift+F9):

docker://docker_web:latest/php -dxdebug.remote_enable=1 -dxdebug.remote_mode=req -dxdebug.remote_port=9000 -dxdebug.remote_host=172.17.0.1 /opt/project/test.php
db

It doesn't resolve! Why would that be, and how can I fix it?

Solution

  • As it happens, my docker environment is built with docker-compose, and all the relevant containers are on the same network, and have a proper depends_on hierarchy.

    However. PHPStorm was actually set up to use plain docker, rather than docker-compose. It was connecting fine to the docker daemon, but because the container wasn't being build composer-aware, it wasn't leveraging the network layout that was defined in my docker-compose.yml. Once I told PHPStorm to use docker-compose, it worked fine.

    As an aside, I noticed that after I run an in-IDE debug session after already loading my container, and causes the container to exit when the script ends. To get around this, I had to create a mirror debug container for PHPStorm to use on demand. My config is as follows:

    version: '3'

services:
  web: &web
    build: ./web
    container_name: dev_web
    ports:
      - "80:80"
    volumes:
      - ${PROJECTS_DIR}/project:/srv/project
      - ./web/logs/httpd:/var/log/httpd
    depends_on:
      - "db"
    networks:
      - backend

  web-debug:
    << : *web
    container_name: dev_web_debug
    ports:
      - "8181:80"
    command: php -v

  db:
    image: mysql
    container_name: dev_db
    ports:
      - "3306:3306"
    volumes:
      - ./db/conf.d:/etc/mysql/conf.d
      - ./db/data:/var/lib/mysql
    environment:
      MYSQL_ROOT_PASSWORD: root
    networks:
      - backend

networks:
  backend:
    driver: bridge

    This allows me to be able to do in-IDE spot debuging on the fly without killing my main web container.