xdebug.md

Using Xdebug

The default development image is shipped with Xdebug, a popular debugger and profiler for PHP.

Because it has a significant performance overhead, the step-by-step debugger is disabled by default. It can be enabled by setting the XDEBUG_MODE environment variable to debug.

On Linux and Mac:

XDEBUG_MODE=debug docker compose up -d

On Windows:

set XDEBUG_MODE=debug&& docker compose up -d&set XDEBUG_MODE=

Debugging with Xdebug and PHPStorm

First, create a PHP debug remote server configuration:

1. In the Settings/Preferences dialog, go to PHP | Servers
2. Create a new server:
   • Name: symfony (or whatever you want to use for the variable PHP_IDE_CONFIG)
   • Host: localhost (or the one defined using the SERVER_NAME environment variable)
   • Port: 443
   • Debugger: Xdebug
   • Check Use path mappings
   • Absolute path on the server: /app

You can now use the debugger!

1. In PHPStorm, open the Run menu and click on Start Listening for PHP Debug Connections

2. Add the XDEBUG_SESSION=PHPSTORM query parameter to the URL of the page you want to debug, or use other available triggers

   Alternatively, you can use the Xdebug extension for your preferred web browser.

3. On command line, we might need to tell PHPStorm which path mapping configuration should be used, set the value of the PHP_IDE_CONFIG environment variable to serverName=symfony, where symfony is the name of the debug server configured higher.

   Example:

   XDEBUG_SESSION=1 PHP_IDE_CONFIG="serverName=symfony" php bin/console ...

Debugging with Xdebug and VScode

1. Install necessery PHP extension for VScode.

2. Add debug configuration into your .vscode\launch.json file.

   Example:

   {
       "name": "Listen for Xdebug",
       "type": "php",
       "request": "launch",
       "port": 9003,
       "pathMappings": {
           "/app": "${workspaceFolder}"
       }
   }
   

3. Use Run and Debug options and run Listen for Xdebug command to listen for upcomming connections with the Xdebug extension installed and active.

Troubleshooting

Inspect the installation with the following command. The Xdebug version should be displayed.

$ docker compose exec php php --version

PHP ...
    with Xdebug v3.x.x ...