Docker - VSCode - XDebug - PHP 7.4

docker-compose.yml

services:
  app:
    volumes:
      - .docker/xdebug.ini:/usr/local/etc/php/conf.d/99-xdebug.ini
    extra_hosts:
      - 'host.internal.docker:host-gateway'

Dockerfile

FROM 7.4-fpm-alpine

RUN apk add php7-pecl-xdebug
RUN cp /usr/lib/php7/modules/xdebug.so /usr/local/lib/php/extensions/no-debug-non-zts-20190902

launch.json

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Listen for XDebug on Docker",
            "type": "php",
            "request": "launch",
            "port": 9000,
            "pathMappings": {
                "/var/www/html/": "${workspaceFolder}"
            }
        }
    ]
}

xdebug.ini

zend_extension=xdebug

[XDebug]

xdebug.client_host=host.internal.docker
xdebug.client_port=9000
xdebug.mode=debug,develop
xdebug.idekey=vsc
xdebug.start_with_request=yes

xdebug.md

In VSCode:

• Install extension: xdebug.php-debug
• Goto settings, update PHP › Debug: Ide Key: "php.debug.ideKey": "vsc"

If host.internal.docker not working, change xdebug.client_host by your IP address:

• macOS: ipconfig getifaddr en0
• Windows with WSL: grep nameserver /etc/resolv.conf | cut -d ' ' -f2
• Linux (Debian based distros): hostname -I | cut -d ' ' -f1

Use XDebug Wizard to get exact installation instructions, then update copy location in Dockerfile.