conda-ship 0.3.0

Conda plugin entry point for the conda-ship runtime builder.

conda-ship

Build ready-to-run conda runtimes from solved conda environments.

conda-ship is a generic builder for single-binary conda runtimes. It provides the cs builder CLI, the cs-template generic runtime template, a composite GitHub Action, and an optional Python adapter that exposes conda ship inside conda.

The project is currently alpha and pre-1.0. The split from conda-express is now explicit: conda-ship owns the reusable build/runtime machinery, while downstream distributions own their package sets, runtime names, release channels, installer wrappers, and user documentation. conda-express is one downstream distribution maintained by Jannis Leidel; it uses conda-ship to publish the cx and cxz runtimes.

Quickstart

This shortest path uses conda-workspaces to create a solved source environment, then builds an online runtime named demo:

conda create -n cs-demo -c conda-forge python pip conda-workspaces
conda activate cs-demo
python -m pip install conda-ship

mkdir demo-runtime
cd demo-runtime
conda workspace init --format conda --name demo-runtime
conda workspace add --feature ship --no-lockfile-update \
  "python>=3.12" \
  "conda>=25.1" \
  conda-rattler-solver \
  "conda-spawn>=0.1.0"
cat >> conda.toml <<'TOML'

[tool.conda-ship]
runtime = "demo"
delegate = "conda"
layout = "online"
source-environment = "ship"
exclude = ["conda-libmamba-solver"]
TOML

conda workspace lock
cs inspect
cs build --dry-run
cs build
./dist/demo --version

For a guided walkthrough with Pixi, bootstrap, status, uninstall, and embedded runtime examples, see the first runtime tutorial.

What It Builds

conda-ship stages a runtime binary plus release metadata:

• .runtime.lock: the lockfile stamped into the runtime
• .packages.txt: tab-separated package records for quick inspection
• .info.json: artifact metadata for release tooling
• .sha256: checksums for staged files
• optional .bundle.tar.zst: compressed package archives for offline builds

The runtime itself has a small management surface: bootstrap, status, shell, and uninstall. Other commands pass through to the configured delegate executable after bootstrap, usually conda.

During bootstrap, generated runtimes also write constructor-compatible conda prefix metadata. The managed prefix gets conda-meta/history and conda-meta/initial-state.explicit.txt in addition to conda-ship's ownership metadata. Conda can recognize the prefix as an environment, and runtimes that include conda-self can use that initial-state snapshot for conda self reset --snapshot installer-updated or conda self reset --snapshot installer-exact.

Artifact Layouts

Layout	Output	Bootstrap behavior
online	<runtime>	Downloads packages from the stamped runtime lock.
external	<runtime> plus <runtime>.bundle.tar.zst	Uses a separate package bundle for offline-capable installs.
embedded	<runtime>z	Embeds the compressed package bundle in one binary.

Project Input

conda-ship builds from an already solved source environment. It does not solve loose matchspecs in the GitHub Action and it does not define a package set of its own.

Supported manifest and lockfile pairs:

• conda.toml plus conda.lock
• pyproject.toml with [tool.conda] plus conda.lock
• pixi.toml plus pixi.lock
• pyproject.toml with [tool.pixi] plus pixi.lock

The package and channel intent lives in the selected source environment. [tool.conda-ship] only records conda-ship build policy:

[tool.conda-ship]
runtime = "demo"
delegate = "conda"
layout = "online"
source-environment = "ship"
exclude = ["conda-libmamba-solver"]

The selected source environment must include the runtime contract packages: conda, conda-rattler-solver, and conda-spawn. Include conda-self in the same source environment when the runtime should expose conda self reset for restoring the bootstrapped base prefix to the initial package set shipped by the runtime.

Local Workflow

Packaged builds find cs-template next to the installed cs executable. Use --template only for an explicit template path, custom packaging, or cross-builds.

cs inspect
cs build --dry-run
cs build
cs build --layout embedded
cs run -- --path /tmp/demo-smoke bootstrap

cs inspect is the preflight command. It derives the runtime lock, validates the selected source environment, applies package exclusions, and prints the package set without writing artifacts.

Use cs build --dry-run to preview the runtime metadata and staged release asset paths before writing files.

After a real build, verify the staged artifacts and inspect the release metadata before handing them to downstream packaging or signing.

The staged runtime is a stamped copy of the generic runtime template with its own command surface before pass-through to the configured delegate.

GitHub Actions

The repository root is also a composite GitHub Action for downstream release jobs:

- uses: jezdez/conda-ship@0.3.0
  id: cs
  with:
    layout: embedded

The action expects a committed manifest and matching lockfile. It downloads the tagged cs, cs-template, and SHA256SUMS release assets for the runner, verifies their GitHub Artifact Attestations, checks the release checksums, runs cs build --dry-run, and then stages the runtime into a dist-path output.

Use release tags for release builds. Branch refs do not have matching conda-ship release assets.

Packaging

conda-ship is not an OS installer generator. It does not target .sh, .pkg, or .msi output directly. It produces runtimes that can be distributed as GitHub Release assets or wrapped by Homebrew, constructor, Docker, enterprise packaging systems, and other release tooling.

The PyPI package installs the cs builder, the cs-template runtime template, and the Python adapter together. The adapter makes conda ship a shortcut for the same builder when installed in a conda environment; it does not make conda-ship part of conda itself. A future conda package should install the same pieces into one environment.

What Belongs Downstream

Downstream distributions decide:

• runtime names and delegates
• package sets and channels
• package exclusions
• install schemes and install names
• documentation URLs
• release channels and installers
• signing, SBOM, and in-toto provenance for final artifacts

conda-ship verifies the inputs it consumes and the package archives it stages or installs, but downstream release systems should sign and attest the final runtime artifacts after cs build.

Documentation

Full documentation is available at jezdez.github.io/conda-ship.

Useful starting points:

• Build your first runtime
• Build in GitHub Actions
• Configuration reference
• Project boundaries

Development

pixi install
pixi run test
pixi run lint
pixi run -e test pytest
pixi run docs

pixi run lint runs the repository's prek hooks, including Rust formatting and clippy checks.

The terminal demos are generated from demos/*.tape with VHS:

pixi run demos
pixi run demos inspect

The tapes build local debug cs and cs-template binaries in hidden setup so the visible commands match the packaged workflow.

Run cargo generate-lockfile after changing Cargo metadata and pixi lock after changing pixi metadata.

License

BSD-3-Clause