Debugging

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# Xdebug

The default Docker stack is shipped without a Xdebug stage. It’s easy though to add Xdebug to your project, for development purposes such as debugging tests or remote API requests.

# Add a Development Stage to the Dockerfile

To avoid deploying API Platform to production with an active Xdebug extension, it’s recommended to add a custom stage to the end of the api/Dockerfile.

# api/Dockerfile
FROM api_platform_php as api_platform_php_dev

ARG XDEBUG_VERSION=3.1.3
RUN set -eux; \
 apk add --no-cache --virtual .build-deps $PHPIZE_DEPS; \
 pecl install xdebug-$XDEBUG_VERSION; \
 docker-php-ext-enable xdebug; \
 apk del .build-deps

# Configure Xdebug with Docker Compose Override

Using an override file named docker-compose.override.yml ensures that the production configuration remains untouched.

As an example, an override could look like this:

version: "3.4"

services:
  php:
    build:
      target: api_platform_php_dev
    environment:
      # See https://docs.docker.com/docker-for-mac/networking/#i-want-to-connect-from-a-container-to-a-service-on-the-host
      # See https://github.com/docker/for-linux/issues/264
      # The `remote_host` below may optionally be replaced with `remote_connect_back`
      # XDEBUG_MODE required for step debugging
      XDEBUG_MODE: debug
      # default port for Xdebug 3 is 9003
      # idekey=VSCODE if you are debugging with VSCode
      XDEBUG_CONFIG: >-
        client_host=host.docker.internal
        idekey=PHPSTORM         
      # This should correspond to the server declared in PHPStorm `Preferences | Languages & Frameworks | PHP | Servers`
      # Then PHPStorm will use the corresponding path mappings
      PHP_IDE_CONFIG: serverName=api-platform

Note for Mac environments use the following:

      XDEBUG_CONFIG: >-
        idekey=PHPSTORM
        client_host=docker.for.mac.localhost

In VSCode, alongside the default PHP configuration in launch.json, you’ll need path mappings for the Docker image.

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Listen for Xdebug",
            "type": "php",
            "request": "launch",
            "port": 9003,
            "log": true,
            "pathMappings": {
                "/srv/api": "${workspaceFolder}/api"
            },
        },
    ]
}

Note: For Linux environments, the client_host setting of host.docker.internal will not work, you will need the actual local IP address of your computer.

# Troubleshooting

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

$ docker-compose exec php \
    php --version

PHP …
    with Xdebug v3.1.3, Copyright (c) 2002-2021, by Derick Rethans
    …

Debugging

Table of Contents

# Xdebug

# Add a Development Stage to the Dockerfile

# Configure Xdebug with Docker Compose Override

# Troubleshooting