devcontainer-rs

This repository hosts a native Rust implementation of the Dev Containers CLI, with compatibility tracked against the pinned upstream TypeScript sources in upstream/ and the pinned specification assets in spec/.

The shipped runtime is the Rust binary in cmd/devcontainer. Node is kept only for lightweight compatibility tooling such as upstream/spec drift checks, generated compatibility inventories, and the parity smoke harness.

Install

Run the CLI without adding it permanently to your environment:

uvx --from devcontainer-rs devcontainer --version
npx @devcontainer-rs/cli --version

Install it with Homebrew:

brew install jooh/devcontainer-rs/devcontainer-rs
devcontainer --version

Homebrew resolves jooh/devcontainer-rs from the tap repository jooh/homebrew-tap.

Stable Runtime Environment Defaults

devcontainer-rs supports convenience environment variables for stable local runtime defaults. These are repo-specific extensions: explicit CLI flags take precedence, and unset or blank environment variables preserve the current defaults.

For Podman-based local use:

export DEVCONTAINER_DOCKER_PATH=podman
export DEVCONTAINER_DOCKER_COMPOSE_PATH=podman-compose
devcontainer up --workspace-folder .

To always refresh a remote image when up creates or recreates the container, use the native --pull-always extension:

devcontainer up --workspace-folder . --pull-always

For plain image configurations, the runtime explicitly pulls the source image. For Compose configurations, it resolves, merges, and interpolates the effective configuration, then determines the active runServices set and its dependency closure. Build-backed services are excluded; for each unique remaining remote image, it directly invokes the selected engine and checks the exit status of each call (pull IMAGE or pull --platform PLATFORM IMAGE). Dockerfile, Compose, and Feature builds use build-stage --pull where needed to refresh remote bases, without force-pulling locally generated final tags such as Feature or UID-update images. During up, this refresh happens before the final existing-container lookup and reuse/start/create decision. An existing container can therefore still be reused after its source is refreshed; combine the option with --remove-existing-container when replacement is required.

To use the same non-standard config path across commands:

export DEVCONTAINER_CONFIG=.devcontainer/podman/devcontainer.json
devcontainer up --workspace-folder .
devcontainer exec uv sync

DEVCONTAINER_CONFIG accepts the same absolute or relative paths as --config. Relative paths resolve against --workspace-folder when it is provided, or the current directory otherwise. Container engine path values are executable paths, not shell command strings with arguments. Use DEVCONTAINER_DOCKER_COMPOSE_PATH=podman-compose, not DEVCONTAINER_DOCKER_COMPOSE_PATH="podman compose".

Why

The main point of all this is to distribute a fat binary that implements dev containers without bringing in the whole node stack. In enterprise contexts this can be helpful.

Eventually we may also extend the upstream devcontainers/cli with additional functionality.

Repository layout

• cmd/devcontainer/: native Rust CLI crate.
• cmd/devcontainer/src/runtime/: native runtime subsystems for container-backed commands.
• acceptance/: repo-owned manual acceptance scenarios and suite manifest.
• upstream/: canonical upstream devcontainers/cli baseline.
• spec/: canonical upstream devcontainers/spec schemas and docs.
• build/: repo-owned compatibility guard scripts.
• src/test/parity/: parity fixtures and golden files for repo-owned checks.
• docs/: contributor and release documentation for the native CLI.

Compatibility contract: this repository targets the exact submodule revision pinned at HEAD:upstream.

Specification contract: schema-sensitive behavior targets the exact submodule revision pinned at HEAD:spec.

Submodules

Initialize submodules before running checks or editing compatibility-sensitive code:

git submodule update --init --recursive

If upstream/ or spec/ is missing or uninitialized, run the same command again and rerun the checks.

Local development

Run the complete local gate before pushing:

make tests

Rust validation:

cargo fmt --manifest-path cmd/devcontainer/Cargo.toml --all -- --check
cargo clippy --manifest-path cmd/devcontainer/Cargo.toml --all-targets --all-features -- -D warnings
cargo check --manifest-path cmd/devcontainer/Cargo.toml --all-targets --all-features
cargo doc --manifest-path cmd/devcontainer/Cargo.toml --no-deps --document-private-items
cargo test --manifest-path cmd/devcontainer/Cargo.toml --locked
cargo deny --manifest-path cmd/devcontainer/Cargo.toml check -A license-not-encountered

CI also enforces the current Rust line coverage baseline:

cargo llvm-cov --manifest-path cmd/devcontainer/Cargo.toml --all-features --workspace --fail-under-lines 95

Compatibility/tooling validation:

npm test
make actionlint-check
make shellcheck

Manual acceptance suite shape:

make acceptance-fixtures-check

The Node-based checks do not require installing project dependencies; they use built-in Node modules only. Node 20+ is still required to run them.

Generated command reference:

npm run generate-cli-reference

Generated parity inventory:

npm run generate-parity-inventory

Enable the repository-managed pre-commit hook:

npm run install-git-hooks

Upstream and spec workflow

When updating upstream compatibility baselines:

git submodule update --init --recursive
git -C upstream fetch origin
git -C upstream checkout <new-upstream-commit>
git add upstream
git rev-parse HEAD:upstream
npm run check-upstream-submodule
npm run check-upstream-compatibility
npm run check-command-matrix
npm run check-parity-inventory
npm run check-parity-harness

When changing schema-sensitive behavior, also verify:

git rev-parse HEAD:spec
npm run check-spec-drift

If a pinned submodule revision changes, update the matching generated baseline files in docs/upstream/.

Contributor notes

• Architecture, command flow, and runtime module ownership: docs/architecture.md
• Generated upstream command reference: docs/upstream/command-reference.md
• Generated parity inventory: docs/upstream/parity-inventory.md
• Native distribution and release notes: docs/standalone/distribution.md
• Runtime and compatibility guardrails: docs/standalone/cutover.md