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Creating DDEV Add-ons

DDEV add-ons provide a powerful way to extend development environments. You can create add-ons using traditional Bash actions or the new PHP-based actions for complex configuration processing.

Quick Start

  1. Use the ddev-addon-template repository
  2. Click “Use this template” to create your own repository
  3. Customize the install.yaml file
  4. Test with tests.bats
  5. Create a release when ready
  6. Add the ddev-get label to your GitHub repository

See this screencast for a walkthrough.

Add-on Structure

Every add-on requires an install.yaml file with these sections:

name: my-addon
pre_install_actions: []
project_files: []
global_files: []
post_install_actions: []
removal_actions: []

Core Sections

  • name: The add-on name used in ddev add-on commands
  • pre_install_actions: Scripts executed before files are copied
  • project_files: Files copied to the project’s .ddev directory
  • global_files: Files copied to the global ~/.ddev/ directory
  • post_install_actions: Scripts executed after files are copied
  • removal_actions: Scripts executed when removing the add-on

Advanced Sections

  • ddev_version_constraint: Minimum DDEV version required
  • dependencies: Other add-ons this add-on depends on
  • yaml_read_files: YAML files to read for template processing

Action Types: Bash vs PHP

Traditional Bash Actions

Bash actions run directly on the host system and are suitable for:

  • File permissions and system commands
  • Environment setup and package installation
  • Direct command execution
  • Simple file operations
name: bash-example

post_install_actions:
  - |
    #ddev-description: Configure project settings
    echo "Setting up project: $DDEV_PROJECT"
    chmod +x .ddev/commands/web/mycommand

PHP-based Actions ✨ NEW

PHP actions provide powerful capabilities for:

  • Complex data processing and YAML manipulation
  • Conditional logic based on project configuration
  • Cross-platform compatibility
  • File content generation and template processing

Why Use PHP Actions?

  • Better YAML processing with the built-in php-yaml extension
  • Cross-platform compatibility (no shell scripting differences)
  • Rich string manipulation and data processing capabilities
  • Access to DDEV project configuration through environment variables
  • Familiar syntax for developers working with PHP projects

Basic PHP Action

name: php-example

post_install_actions:
  - |
    <?php
    #ddev-description: Process project configuration

    // Access DDEV environment variables
    $projectName = $_ENV['DDEV_PROJECT'];
    $projectType = $_ENV['DDEV_PROJECT_TYPE'];
    $docroot = $_ENV['DDEV_DOCROOT'];

    echo "Setting up $projectType project: $projectName\n";

    // Generate YAML configuration
    $config = [
        'services' => [
            'myservice' => [
                'image' => 'nginx:latest',
                'environment' => [
                    'PROJECT_TYPE' => $projectType
                ]
            ]
        ]
    ];

    file_put_contents('docker-compose.myservice.yaml',
        "#ddev-generated\n" . yaml_emit($config));
    ?>

Available Environment Variables

PHP actions have access to all standard DDEV environment variables:

<?php
// Project Information
$_ENV['DDEV_PROJECT']        // Project name
$_ENV['DDEV_PROJECT_TYPE']   // 'drupal', 'wordpress', 'laravel', etc.
$_ENV['DDEV_APPROOT']        // '/var/www/html' (project root)
$_ENV['DDEV_DOCROOT']        // 'web', 'public', or configured docroot
$_ENV['DDEV_TLD']            // 'ddev.site' or configured TLD

// Technology Stack  
$_ENV['DDEV_PHP_VERSION']    // '8.1', '8.2', '8.3', etc.
$_ENV['DDEV_WEBSERVER_TYPE'] // 'nginx-fpm', 'apache-fpm'
$_ENV['DDEV_DATABASE']       // 'mysql:8.0', 'postgres:16', etc.
$_ENV['DDEV_DATABASE_FAMILY'] // 'mysql', 'postgres'

// System Information
$_ENV['DDEV_VERSION']        // Current DDEV version
$_ENV['DDEV_MUTAGEN_ENABLED'] // 'true' or 'false'
?>

PHP Action Execution Environment

  • Working directory: /var/www/html/.ddev (your project’s .ddev directory)
  • Project access: Full read/write access to project repository at /var/www/html/
  • Error handling: Automatic strict error handling (equivalent to Bash set -eu)
  • Extensions: php-yaml extension for robust YAML processing

Advanced PHP Example: Conditional Configuration

name: conditional-config

pre_install_actions:
  - |
    <?php
    #ddev-description: Generate environment-specific configuration

    $projectType = $_ENV['DDEV_PROJECT_TYPE'];
    $services = [];

    // Different services based on project type
    switch($projectType) {
        case 'drupal':
            $services['redis'] = [
                'image' => 'redis:7-alpine',
                'ports' => ['6379:6379']
            ];
            break;
        case 'wordpress':
            $services['memcached'] = [
                'image' => 'memcached:alpine', 
                'ports' => ['11211:11211']
            ];
            break;
        default:
            $services['cache'] = [
                'image' => 'nginx:alpine'
            ];
    }

    $composeContent = ['services' => $services];
    file_put_contents('docker-compose.conditional.yaml',
        "#ddev-generated\n" . yaml_emit($composeContent));

    echo "Generated configuration for $projectType project\n";
    ?>

Separate PHP Script Files (Best Practice)

For complex logic, create separate PHP script files using your add-on’s namespace:

File structure:

.ddev/
├── install.yaml
└── myservice/
    └── scripts/
        ├── setup.php
        └── configure.php

Clean install.yaml:

name: myservice

project_files:
  - myservice/scripts/setup.php
  - myservice/scripts/configure.php

post_install_actions:
  - |
    <?php
    #ddev-description: Configure project
    require 'myservice/scripts/setup.php';
  - |
    <?php
    #ddev-description: Apply optimizations
    require 'myservice/scripts/configure.php';

myservice/scripts/setup.php:

<?php
#ddev-generated

$projectType = $_ENV['DDEV_PROJECT_TYPE']; 
$docroot = $_ENV['DDEV_DOCROOT'];

// Exit early if not applicable
if ($projectType !== 'drupal') {
    echo "Not a Drupal project, skipping\n";
    exit(0);
}

// Perform Drupal-specific setup
$settingsFile = "/var/www/html/{$docroot}/sites/default/settings.ddev.php";
$settings = "<?php\n// DDEV-generated settings\n";
file_put_contents($settingsFile, $settings);

echo "Drupal settings configured\n";

Real-world example: ddev-redis structure

.ddev/
├── install.yaml
├── docker-compose.redis.yaml
└── redis/
    └── scripts/
        ├── setup-drupal-settings.php
        ├── setup-redis-optimized-config.php
        └── settings.ddev.redis.php

Mixed Bash and PHP Actions

You can combine both approaches in a single add-on:

name: mixed-actions

pre_install_actions:
  - |
    #ddev-description: Set file permissions
    chmod +x .ddev/commands/web/mycommand

  - |
    <?php
    #ddev-description: Process configuration
    $projectName = $_ENV['DDEV_PROJECT'];
    echo "Processing config for: $projectName\n";
    ?>

Advanced Features

Version Constraints

Specify minimum DDEV version requirements:

ddev_version_constraint: '>= v1.24.8'

Dependencies

Declare add-on dependencies that will be automatically installed:

dependencies:
  - ddev/ddev-redis        # GitHub repository
  - https://example.com/addon.tar.gz  # Direct tarball URL

Dependencies are automatically installed when the add-on is installed. If a dependency is missing, DDEV will:

  1. Automatically install it using the same formats supported by ddev add-on get
  2. Detect circular dependencies and prevent infinite loops
  3. Install recursively - dependencies of dependencies are also installed

To skip automatic dependency installation, use the --skip-deps flag:

ddev add-on get --skip-deps my-addon

This does not install dependencies. Ensure required dependencies are present if your add-on relies on them.

Runtime Dependencies (Advanced)

Advanced Feature

Runtime dependencies are an advanced, rarely-used feature for sophisticated add-ons that need to dynamically discover dependencies during installation. Most add-ons should use static dependencies declared in install.yaml instead.

Runtime dependencies allow add-ons to dynamically discover and install dependencies during the installation process, rather than declaring them statically. This enables complex scenarios like:

  • Service detection - Analyzing project configuration to determine needed services
  • Conditional dependencies - Installing different add-ons based on project analysis
  • Dynamic configuration processing - Dependencies determined by parsing external files

How Runtime Dependencies Work

  1. Detection Phase: During pre-install or post-install actions, your add-on analyzes the project
  2. Creation Phase: Your add-on creates a .runtime-deps-<addon-name> file listing discovered dependencies
  3. Processing Phase: After installation completes, DDEV automatically processes runtime dependencies
  4. Installation Phase: DDEV installs any missing dependencies and cleans up the runtime dependencies file

Creating Runtime Dependencies

Create a .runtime-deps-<addon-name> file in the project’s .ddev directory with one dependency per line:

Example: Dynamic service detection in post-install action
name: my-dynamic-addon

post_install_actions:
  - |
    <?php
    #ddev-description: Detect required services dynamically

    $services = [];

    // Analyze project configuration
    if (file_exists('/var/www/html/.platform.yaml')) {
        $config = yaml_parse_file('/var/www/html/.platform.yaml');

        // Check for Redis usage
        if (isset($config['services']['cache']['type']) && 
            strpos($config['services']['cache']['type'], 'redis') !== false) {
            $services[] = 'ddev/ddev-redis';
        }

        // Check for Elasticsearch usage
        if (isset($config['services']['search']['type']) && 
            strpos($config['services']['search']['type'], 'elasticsearch') !== false) {
            $services[] = 'ddev/ddev-elasticsearch';
        }
    }

    // Create runtime dependencies file if services were found
    if (!empty($services)) {
        $runtimeDepsFile = '.runtime-deps-my-dynamic-addon';
        file_put_contents($runtimeDepsFile, implode("\n", $services) . "\n");
        echo "Created runtime dependencies for " . count($services) . " service(s)\n";
    }
    ?>

Runtime Dependencies File Format

The .runtime-deps-<addon-name> file uses the same dependency formats as static dependencies:

# One dependency per line
ddev/ddev-redis
ddev/ddev-elasticsearch
https://example.com/addon.tar.gz

# Comments and empty lines are ignored

Processing Timing

Runtime dependencies are processed after all installation phases complete:

  1. Pre-install actions execute
  2. Project files are copied
  3. Global files are copied
  4. Post-install actions execute
  5. Runtime dependencies are processed ← This happens last
  6. Cleanup occurs

This timing ensures that:

  • Add-ons can analyze the fully installed project state
  • Post-install actions can create runtime dependencies based on project configuration
  • Dependencies have access to all project files when they install

Real-world Example: Upsun Integration

The ddev-upsun add-on demonstrates runtime dependencies by:

  1. Analyzing .upsun/config.yaml during post-install
  2. Detecting services like Redis, Elasticsearch, Memcached
  3. Creating runtime dependencies for corresponding DDEV add-ons
  4. Automatically installing the required service add-ons
<?php
// Simplified example from ddev-upsun
$detectedServices = analyzeUpsunConfig('/var/www/html/.upsun/config.yaml');
$dependencies = [];

foreach ($detectedServices as $service) {
    switch ($service['type']) {
        case 'redis':
            $dependencies[] = 'ddev/ddev-redis';
            break;
        case 'opensearch':
            $dependencies[] = 'ddev/ddev-opensearch';
            break;
    }
}

if (!empty($dependencies)) {
    file_put_contents('.runtime-deps-upsun', implode("\n", $dependencies));
}
?>

When NOT to Use Runtime Dependencies

Use static dependencies instead if:

  • Dependencies are always required
  • Dependencies don’t change based on project analysis
  • You want simpler, more predictable behavior

Use runtime dependencies only if:

  • Dependencies must be determined by analyzing project files
  • Different projects need different dependencies
  • You’re integrating with external platform configurations

Debugging Runtime Dependencies

Add verbose logging to debug runtime dependency processing:

ddev add-on get --verbose your-addon

This will show:

  • When runtime dependencies files are created
  • What dependencies are discovered
  • Installation progress for each dependency

Limitations

  • Runtime dependencies cannot create circular dependency loops
  • The .runtime-deps-* file is automatically deleted after processing
  • Runtime dependencies are not processed when using --skip-deps
  • Cannot be used to conditionally install the add-on itself

Template Replacements (Advanced, Very Unusual)

Use environment variables in filenames and content:

project_files:
  - "settings.${DDEV_PROJECT}.php"

YAML File Processing

Read project YAML files for advanced templating:

yaml_read_files:
  config: "config.yaml"

post_install_actions:
  - |
    <?php
    // Access YAML data via templating: {{ .config.some_value }}
    ?>

Error Handling

Use proper exit codes and error messages:

<?php
#ddev-description: Validate requirements

if (empty($_ENV['DDEV_PROJECT'])) {
    echo "Error: DDEV environment not available\n";
    exit(1);
}

// Continue with setup...
echo "Requirements validated\n";
?>

Special Directives

Description Display

Add descriptions to your actions:

#ddev-description: Installing Redis configuration

<?php
#ddev-description: Processing project settings
?>

Warning Exit Codes

Treat specific exit codes as warnings instead of errors:

post_install_actions:
  - |
    #ddev-warning-exit-code: 2
    #ddev-description: Optional configuration
    some-command-that-might-fail

Testing Your Add-on

Bats Testing Framework

The add-on template includes a tests.bats file for testing:

#!/usr/bin/env bats

@test "install add-on" {
  ddev add-on get . --project my-test
  cd my-test
  ddev restart
  # Add your tests here
}

@test "verify service is running" {
  cd my-test
  ddev exec "curl -s http://myservice:8080/health"
}

Run tests with:

bats tests.bats

Manual Testing

  1. Create a test DDEV project
  2. Install your add-on locally:
ddev add-on get /path/to/your/addon
  1. Verify services start correctly
  2. Test configuration options
  3. Test removal process

Publishing Your Add-on

Repository Setup

  1. Test thoroughly using the test framework
  2. Create proper releases with semantic versioning
  3. Add the ddev-get label to your GitHub repository
  4. Write clear documentation in your readme
  5. Include examples and configuration options

Making it Official

To become an officially supported add-on:

  1. Open an issue in the DDEV repository
  2. Request upgrade to official status
  3. Commit to maintaining the add-on
  4. Subscribe to repository activity and be responsive

Best Practices

  • Follow semantic versioning for releases
  • Maintain backward compatibility when possible
  • Test with different DDEV versions
  • Update dependencies regularly
  • Respond to user issues promptly
  • Keep documentation up to date
  • Use namespaced directories (e.g., myservice/scripts/ not just scripts/)

Examples and References

Getting Help

Creating DDEV add-ons is a powerful way to contribute to the DDEV ecosystem. Whether you use traditional Bash actions or the new PHP-based actions, you can create sophisticated extensions that help developers worldwide.