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Devilbox

Docker on Linux: Xdebug for Sublime Text 3

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Docker on Linux: Xdebug for Sublime Text

Use this guide to debug Devilbox projects with Sublime Text 4, the xdebug-client package, PHP 8.3 or 8.4, and Xdebug 3 on Docker Engine for Linux.

Prerequisites

  • A running Devilbox checkout on Linux.
  • Sublime Text 4 with Package Control installed.
  • The xdebug-client package installed from Package Control.
  • A project below ./data/www or the directory configured for HTTPD data.

See also: Xdebug options explained.

Assumptions

SettingExample
Devilbox directory/home/cytopia/repo/devilbox
Local project path/home/cytopia/repo/devilbox/data/www/myapp
Container project path/shared/httpd/myapp
PHP version8.4
Xdebug client hosthost.docker.internal
Xdebug client port9003

The local project path is where Sublime opens your files. The container path is what PHP reports to the debug client.

Configure Sublime Text 4

  1. Install xdebug-client with Package Control.
  2. Open Preferences | Package Settings | Xdebug Client | Settings.
  3. Configure the listener and path mapping for your project.
{
  "path_mapping": {
    "/shared/httpd/myapp": "/home/cytopia/repo/devilbox/data/www/myapp"
  },
  "url": "http://myapp.lvh.me/",
  "ide_key": "sublime.xdebug",
  "host": "0.0.0.0",
  "port": 9003
}

Start the Sublime debug listener before loading the page in your browser.

Configure Xdebug 3

Create cfg/php-ini-8.4/xdebug.ini in your Devilbox checkout. Use cfg/php-ini-8.3/xdebug.ini if your project runs on PHP 8.3.

Terminal window
host> cd /home/cytopia/repo/devilbox
host> vi cfg/php-ini-8.4/xdebug.ini

Add the current Xdebug 3 settings:

zend_extension=xdebug.so


xdebug.mode=debug
xdebug.client_host=host.docker.internal
xdebug.client_port=9003
xdebug.start_with_request=yes
xdebug.idekey=sublime.xdebug


; Optional, useful while testing connections
xdebug.log=/var/log/php/xdebug.log

If host.docker.internal is not available in your custom Linux setup, replace it with the host IP address reachable from the PHP container.

Restart Devilbox

Restart the PHP container so the new ini file is loaded:

Terminal window
host> cd /home/cytopia/repo/devilbox
host> docker-compose stop php
host> docker-compose rm -f php
host> docker-compose up php httpd bind

Open your project URL with the Sublime listener active. Sublime should stop at breakpoints once the path mapping matches the container path.