Docker

Mozart provides Docker images for multiple architectures (linux/amd64, linux/arm64, and linux/arm/v7), making it compatible with Intel/AMD systems, Apple Silicon Macs, ARM-based servers, and Raspberry Pi devices (including Raspberry Pi 3 and earlier).

Image registries

Mozart images are available from two registries:

• Docker Hub: coenjacobs/mozart
• GitHub Container Registry: ghcr.io/coenjacobs/mozart

Tag strategy

• latest: Points to the highest stable version (e.g., 1.0.0). This is the recommended tag for production use.
• dev: Points to the latest commit on the master branch. Use this for testing bleeding-edge features.
• Version tags: Specific versions like 1.0.0, 1.0.0-beta.1, etc. Use these for reproducible builds.
• Version aliases: Shortcuts like 1 (latest 1.x.x) and 1.0 (latest 1.0.x) are available for convenience.

Pulling images

From Docker Hub:

docker pull coenjacobs/mozart

From GitHub Container Registry:

docker pull ghcr.io/coenjacobs/mozart

Pull a specific version:

docker pull coenjacobs/mozart:1.0.0

Pull development build:

docker pull coenjacobs/mozart:dev

You can see all available tags on Docker Hub or on GitHub Container Registry.

Running Mozart

Start the container and run the mozart compose command in a single command:

docker run --rm -it -v ${PWD}:/project/ coenjacobs/mozart /mozart/bin/mozart compose

This command automatically adds the current working directory as a volume into the designated directory for the project: /project/. In the Docker container, Mozart is installed in the /mozart/ directory. Using the above command will run Mozart on the current working directory.

Dockerfile stages

The Dockerfile uses multi-stage builds. Each stage serves a different purpose:

Stage	Base	Purpose
base	php:${PHP_VERSION}-cli-alpine	Bare PHP CLI image, shared by all stages
builder	base	Adds git, Composer, installs all dependencies. Used for CI testing.
develop	builder	Adds Xdebug for local development and debugging
packager	builder	Reinstalls dependencies with --no-dev for production
application	base	Final production image. Copies only built artifacts from packager.

The PHP_VERSION build arg defaults to 8.5 and is overridden by CI to test against multiple PHP versions (8.2 through 8.5).

Docker Compose services

docker-compose.yml defines two services for development and testing:

Service	Dockerfile target	Volume mount	Xdebug	Use case
builder	develop	Yes (.:/mozart/)	Yes	Local development — code changes reflected immediately
actions-tester	builder	No	No	CI simulation — files copied at build time

The builder service is what you use for local development. It mounts the working directory so edits are reflected without rebuilding. The actions-tester service mirrors how CI runs tests: files are baked into the image at build time, so you must rebuild (docker compose build actions-tester) after code changes.

Both services accept a PHP_VERSION environment variable (defaults to 8.5).

PHP configuration

The docker/php/ directory contains PHP configuration overrides:

• error_reporting.ini — Sets error_reporting=E_ALL
• xdebug.ini — Configures Xdebug with mode=develop, connecting to host.docker.internal (only loaded in the develop stage)

See also

• testing.md — Running tests with Docker