Missing Multi-Stage Build

The Problem

Docker builds your image in a single stage. That means the final image contains Composer, its dependencies, and any build tooling — none of which belong in production.

Right now your image is unnecessarily large. Multi-stage builds let you use a heavy builder image to install dependencies, then throw it away and copy only the artifacts you need into a lean runtime image.

What You Need to Fix

Load this challenge:

php artisan challenge:start docker-missing-multistage

A Dockerfile is copied into your project root. It works — but it installs Composer directly into the final image. This is the broken pattern you need to fix.

Open the Dockerfile. You'll see three problems:

1. No builder stage — there's only one FROM block, and it installs everything into the same image that runs PHP-FPM in production
2. Composer binary copied into the runtime image — the line COPY --from=composer:2 /usr/bin/composer /usr/bin/composer puts Composer where it doesn't belong
3. No HEALTHCHECK — Docker has no way to know whether PHP-FPM is actually accepting requests, only that the process is alive

What You Must Do

Convert the Dockerfile to a proper two-stage build:

Stage 1: builder

Use FROM composer:2 AS builder as your first stage. This image has PHP and Composer pre-installed. Your job in this stage is only to install dependencies:

WORKDIR /app
COPY composer.json composer.lock ./
RUN composer install --no-dev --no-interaction --optimize-autoloader

Stage 2: runtime

Start fresh with FROM php:8.2-fpm-alpine. Install extensions. Then copy the vendor directory from the builder — not Composer itself:

COPY --from=builder /app/vendor ./vendor

Remove COPY --from=composer:2 /usr/bin/composer /usr/bin/composer entirely — that line installs the Composer binary into your production image, which is what you're trying to avoid.

Add a HEALTHCHECK

Before the CMD, add a HEALTHCHECK that tests PHP-FPM's configuration:

HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
  CMD php-fpm -t || exit 1

Hints

• The first FROM should be FROM composer:2 AS builder and sets up a temporary build environment
• The second FROM is FROM php:8.2-fpm-alpine — this is the image that actually runs in production
• COPY --from=builder /app/vendor ./vendor pulls the installed vendor/ directory from the builder stage into the runtime image
• HEALTHCHECK goes after the EXPOSE instruction, before CMD

Verify

php artisan challenge:verify

All five checks must pass.