docker-for-apple-container 0.1.2

Docker CLI compatibility shim over Apple's container CLI.

docker-for-apple-container

Run docker and docker compose on macOS, backed by Apple's native container CLI. No Docker Desktop.

Website: https://appautomaton.github.io/docker-for-apple-container/ · PyPI: https://pypi.org/project/docker-for-apple-container/

docker-for-apple-container is a small docker command wrapper for Apple's container CLI. It lets tools that expect a docker binary run against Apple container on macOS, without installing Docker Desktop, Podman, or a third-party adapter.

It is a stateless translator, not a Docker replacement. It maps each Docker command to a clean Apple container equivalent and fails loudly on the rest. Apple container is the single source of truth, so the shim persists nothing of its own (no sidecar file, registry, or database). Even docker compose stays stateless: project membership is stored as labels in Apple's own object store, exactly as Docker Compose does, so every verb reconstructs the project by querying Apple rather than reading shim-owned state.

Install

Every method below gives you a docker command backed by Apple container. Use them on a Mac that runs Apple container rather than Docker Desktop.

With Homebrew:

brew install appautomaton/tap/docker-for-apple-container

With pip:

pip install docker-for-apple-container

From source, symlink the launcher onto your PATH:

git clone https://github.com/appautomaton/docker-for-apple-container.git
cd docker-for-apple-container
ln -sf "$(pwd)/bin/docker" ~/.local/bin/docker

After any of these, run docker as usual. If a tool resolves its Docker binary from an environment variable or config setting, point that at the installed docker (or the repo's bin/docker).

Requirements

• macOS with Apple container 1.0.0
• Python 3.9+ (standard library only, no third-party packages)
• container system status should report the apiserver as running

Start it with:

container system start

Supported Docker Subset

Three tiers. Anything outside them fails with an explicit exit-64 error instead of pretending to work.

Fully translated (the core contract)

• docker version
• docker info --format "{{.Driver}}"
• docker build -f DOCKERFILE -t TAG CONTEXT
• docker image inspect IMAGE --format "{{json .Config.Entrypoint}}"
• docker run -d ... IMAGE CMD...
• docker create ... IMAGE CMD... uses the same flag translation as run and prints the new container ID
• docker ps -a --filter ... --format ...
• docker inspect --format "{{.State.FinishedAt}}" CONTAINER
• docker start CONTAINER
• docker exec [-i] [-e KEY=VALUE] CONTAINER CMD...
• docker stop -t N CONTAINER
• docker rm [-f] CONTAINER

Translated extras

• docker logs [-f] [--tail N] CONTAINER. --tail N maps to Apple -n N (and --tail all to "print all"). --since and --timestamps have no Apple equivalent, so they are refused.
• docker stats [--no-stream] CONTAINER. Go-template --format is refused. Apple --format accepts only json|table|yaml|toml.
• docker cp SRC DEST. The positional container:path form maps 1:1 onto Apple container copy. Docker -a and -L flags are refused.
• docker restart [-t N] CONTAINER..., composed from stop + start (Apple has no restart). No state is kept between the two calls.
• docker export [-o FILE] CONTAINER maps onto container export -o. Note: Apple container export requires the container to be stopped (Docker also exports running ones). The shim surfaces Apple's "container is not stopped" error rather than silently stopping it for you.
• docker login [-u USER] [--password-stdin] SERVER and docker logout SERVER delegate to container registry login/logout. Apple stores the credential. The shim keeps nothing. Docker -p/--password is refused in favor of --password-stdin.
• docker system info maps to docker info. docker system prune [--volumes] runs Apple's prune + image prune + network prune (+ volume prune). It is non-interactive: there is no confirmation prompt, and -f/-a are no-ops.

Thin passthrough (basic forms only)

docker images, docker pull, docker push, docker tag, docker save, docker load, docker rmi (top-level aliases for docker image <sub>), docker image <sub> (pull/rm/tag/push/save/load/prune/ls), docker network <sub> and docker volume <sub> (create/ls/rm/inspect/prune), and docker kill [-s SIG] forward to the matching Apple container command. Subcommand names and common flags line up, but Docker-only flags are not translated. Go-template --format on ls-style commands is refused rather than mis-forwarded, and subcommands Apple lacks (e.g. network connect) fail loudly.

Compose (stateless orchestration)

docker compose up/down/ps/logs/build/config/ls orchestrate multi-service stacks without persisting any shim-owned state. Apple container has no native compose, so the shim parses the compose file and issues a sequence of container commands, but it keeps no project file. Instead every resource is tagged with Docker's own label schema (com.docker.compose.project, com.docker.compose.service, and so on) on the containers, the project network, and any named volumes. down/ps/logs/ls reconstruct the project purely by querying Apple and filtering on those labels. Only up/build/config need to read the compose file.

• Project name resolves like Docker: -p NAME → COMPOSE_PROJECT_NAME → the file's name: → the directory basename.
• Service discovery. Apple does not resolve service names by DNS without an admin container system dns domain. Instead, after services start, the shim appends <ip> <service> lines to each container's own /etc/hosts file (IPs read live from container inspect). That file lives in the container's ephemeral layer and is discarded when the container is removed. The macOS host's /etc/hosts is never touched.
• host.docker.internal. The same /etc/hosts injection also publishes host.docker.internal and gateway.docker.internal pointing at the container's gateway, which on Apple container is the macOS host. This mirrors Docker Desktop (which adds these names automatically on macOS/Windows), so a service that dials the host by that name (for example http://host.docker.internal:8317) works unchanged. The gateway is read per-network from container inspect, not hardcoded. Injection is idempotent and skipped with a warning on shell-less images (e.g. distroless). It is compose-only. Bare docker run is left alone, since injecting into a possibly short-lived container would race its exit (Apple has no --add-host flag to set it at creation, so it must be done via a post-start exec).
• Named volumes map onto Apple-native volumes (container volume create), scoped as <project>_<volume>. Host-path mounts become bind mounts, with relative paths resolved against the compose file's directory.
• Teardown is self-coherent. down removes the project's containers (found by label), then removes the network (and with -v, the volumes) only if the shim created them (verified via the project label), never external ones.
• up is idempotent: it removes the project's previous containers before recreating, so re-running never accumulates duplicates.
• YAML is parsed by a small dependency-free subset parser (block maps and sequences, flow collections, quoted scalars, comments, and ${VAR:-default} interpolation). Anchors, multi-document streams, and |/> block scalars are out of scope.

Compose keys with no Apple equivalent (restart, healthcheck, privileged, hostname, secrets, configs, deploy replicas, and the like) are parsed but ignored, with a one-line warning per key so behavior is never silently misrepresented.

Refused, by design

Commands and flags with no verified Apple equivalent fail loudly: docker system events (a stateful watcher), docker commit/diff/rename/ history/import (no Apple equivalent), docker run --network=none, docker run --add-host/--hostname, and any unknown command.

Caveats

• --security-opt, --pids-limit, and --storage-opt on run are accepted as silent no-ops. Apple container documents no equivalent, so a container may be less constrained than the flag implies.
• docker run -v host:ctr:ro becomes an Apple --mount bind (only ro mode is honored). --tmpfs option suffixes are reduced to the mount path.

State

The shim is stateless. It does not persist Docker-shaped metadata, cache files, or a support directory. Apple container is the source of truth, so direct Apple container changes are reflected on the next shim command. Compose is no exception: project bookkeeping lives in Apple's label store, not in any shim-owned file. See the Compose section above.

Tests

Unit tests use a fake container binary and do not start real containers. They cover the core Docker command contract in tests/test_hermes_contract.py, and compose in tests/test_compose.py (parser, interpolation, topo sort, translation, and label-based orchestration):

python3 -m unittest discover -s tests -v

Live smoke testing against Apple container is intentionally manual because it starts and removes containers. The compose path has been verified end-to-end against Apple container 1.0.0 (multi-service up, label reconstruction, service-name resolution, build:, named volumes, and clean down/down -v).