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Detection

migetpacks detects a PHP application when any of the following files are present in the project root:
  • composer.json
  • index.php

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Version Detection

PHP version is resolved in the following priority order:
SourceExample
.php-version8.3
composer.json (require.php)"php": ">=8.2"
Default8.3
Version constraints from composer.json (e.g., >=8.2, ^8.3) are normalized to Docker-compatible versions.
FrankenPHP supports PHP 8.2, 8.3, and 8.4. Older versions will fall back to PHP 8.2 with a warning.

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Build Process

migetpacks generates a multi-stage Dockerfile using FrankenPHP (a modern PHP application server built on Go and Caddy): 
# Build stage
FROM dunglas/frankenphp:builder-php8.3 AS builder
WORKDIR /build

# Install PHP extensions detected from composer.json
RUN apt-get update && apt-get install -y ... \
    && docker-php-ext-install pdo_pgsql gd ...

# Layer caching: copy dependency files first
COPY composer.json composer.lock* ./

# Install Composer and dependencies (cached if lockfiles unchanged)
RUN curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer \
    && composer install --no-dev --optimize-autoloader --no-scripts

# Copy source code
COPY . .

# Runtime stage
FROM dunglas/frankenphp:php8.3
WORKDIR /app
COPY --from=builder --chown=1000:1000 /build /app

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PHP Extension Detection

Extensions declared in composer.json under require with the ext- prefix are automatically installed: 
{
  "require": {
    "ext-pdo_pgsql": "*",
    "ext-gd": "*",
    "ext-intl": "*"
  }
}

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Web Root Detection

migetpacks automatically detects the web root directory by checking for these directories (in order):
  1. web/
  2. public/
  3. html/
  4. www/
  5. . (project root, fallback)

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Run Command

The default run command uses FrankenPHP with Caddy: 
frankenphp run --config /etc/caddy/Caddyfile
Override with RUN_COMMAND or a Procfile: 
web: frankenphp run --config /etc/caddy/Caddyfile

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PHP Configuration

Production PHP settings are automatically configured via environment variables:
SettingDefault
memory_limit256M
max_execution_time30
upload_max_filesize32M
opcache.enable1
display_errorsOff
session.cookie_secure1
These can be overridden at runtime by setting the corresponding PHP_INI_* environment variable (e.g., PHP_INI_MEMORY_LIMIT=512M).

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Caching

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Layer Caching

Dependencies are cached by copying composer.json and composer.lock before the full source:
ScenarioDependency Install
First buildRuns
Source code change onlyCached
Lockfile changeRuns

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BUILD_CACHE_DIR

When BUILD_CACHE_DIR is set, Composer packages are cached at:
Cache PathContents
/cache/composerComposer package cache

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DHI Support

Docker Hardened Images (DHI) are not supported for PHP. FrankenPHP is a specialized application server that requires its own base image.
When USE_DHI=true is set, migetpacks will continue to use the standard FrankenPHP images.

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Example

docker run --rm \
  -v /path/to/php-app:/workspace/source \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e OUTPUT_IMAGE=my-php-app:latest \
  miget/migetpacks:latest

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With custom environment variables

docker run --rm \
  -v /path/to/php-app:/workspace/source \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e OUTPUT_IMAGE=my-php-app:latest \
  -e PHP_INI_MEMORY_LIMIT=512M \
  -e APP_ENV=production \
  miget/migetpacks:latest