version: "1.0.0" name: litestar-build description: "Auto-activate for uv build, hatch build, PyApp, PYAPP_*, wheel assets, GitHub release matrices, cargo-zigbuild, or python-build-standalone. Not for runtime deployment."

litestar-build

Build-side packaging patterns for Litestar applications: how to produce a self-contained wheel that embeds the Vite/Bun frontend, how to wrap that wheel in a PyApp onefile binary, and how to wire the whole pipeline into GitHub Actions CI and releases.

This skill is the counterpart to litestar-deployment — build is about producing artifacts, deployment is about running them.

The Core Idea: One Wheel, Self-Contained

A Litestar wheel is the single source of truth for a release. It contains:

• Python code (src/py/app/ or app/)
• SQL migrations, Jinja templates, INI configs
• The built Vite/Bun frontend bundle (JS, CSS, HTML, images)
• Email templates rendered from React/MJX to static HTML

Once produced, that wheel can be:

1. pip installed into a container (litestar-deployment).
2. Wrapped in a PyApp binary (dist/<app>, dist/app-x86_64-linux-gnu) for zero-dep distribution.
3. Uploaded to PyPI or a private index.

All three paths assume the wheel is already complete — no bun run build happens at deploy/install time.

Why bundle assets into the wheel (and not serve from a CDN)

For most Litestar apps that ship as a product (CLIs, internal tools, enterprise installers), bundled-in-wheel is correct. Projects like litestar-fullstack-inertia and litestar-fullstack all bundle.

Why litestar-vite configs look the way they do in reference apps

This is the piece most developers miss. The Vite/litestar-vite configs in the reference apps are deliberately set up so the Vite output lands inside the Python package directory — because that's what makes the wheel pick them up automatically.

litestar-fullstack (src/js/web/vite.config.ts):

export default defineConfig({
  build: {
    outDir: path.resolve(__dirname, "../../py/app/server/static/web"),  // ← inside src/py/app/ (the Python package)
    emptyOutDir: true,
  },
  plugins: [
    litestar({
      bundleDir: path.resolve(__dirname, "../../py/app/server/static/web"),
      hotFile: path.resolve(__dirname, "../../py/app/server/static/web/hot"),
    }),
  ],
})

litestar-fullstack-inertia — in litestar-vite v0.30+, Python ViteConfig(paths=PathConfig(bundle_dir=...)) is the single source of truth and writes .litestar.json on startup/CLI invocation so litestar({ input: [...] }) in vite.config.ts inherits bundleDir and hotFile automatically:

def get_vite_config() -> ViteConfig:
    """Configure litestar-vite to emit assets inside the app/ Python package."""
    return ViteConfig(
        paths=PathConfig(
            root=BASE_DIR.parent,
            bundle_dir=Path("app/domain/web/public"),
            resource_dir=Path("resources"),
        ),
    )

Advanced reference pattern — same approach: Vite and the offline-report build write to src/py/<app>/server/public/ and src/py/<app>/domain/web/static/reports/offline/, both under the package root.

Contrast with a naïve vite build that writes to ./dist/ at the repo root: those files are outside the package directory listed in [tool.hatch.build.targets.wheel] packages = [...], so Hatchling silently drops them. The wheel ships without a frontend.

Rule: Vite's `outDir` and litestar-vite's `bundle_dir` must point inside one of the Python packages that Hatchling is told to include. Everything else flows from that.

Code Style Rules

• Emit all compiled frontend bundles (PathConfig.bundle_dir / Vite build.outDir) inside a Python package directory included by Hatchling (app/... or src/py/<pkg>/...).
• Choose exactly one Hatchling asset inclusion strategy ([tool.hatch.build.targets.wheel.force-include] OR ignore-vcs = true) — never combine both.
• Guard custom Hatchling build hooks (BuildHookInterface.initialize) with if version == "editable": return so uv sync succeeds before frontend assets are built, and exclude tools/build from mypy and pyright.
• Run asset compilation, static template generation, and license collection before uv build --wheel --clear.
• Treat PYAPP_* configuration variables (PYAPP_PROJECT_PATH, PYAPP_PYTHON_VERSION, PYAPP_DISTRIBUTION_EMBED, PYAPP_DISTRIBUTION_VARIANT_GIL, PYAPP_SKIP_INSTALL) as compile-time inputs to cargo build / cargo zigbuild; at runtime, inspect os.getenv("PYAPP") ("1" or path when running under Pass-Through) to detect PyApp execution.
• Use cargo zigbuild --release --target <arch>-unknown-linux-gnu.2.17 with BZIP2_SYS_STATIC=1 and LZMA_API_STATIC=1 when building portable Linux PyApp binaries.

Quick Reference

Canonical Makefile Build Graph

Every Litestar app with bundled assets has some variant of this:

.PHONY: install build-assets build-wheel build-onefile
 
install:                          ## Install Python + JS deps
	@uv sync --all-groups
	@cd src/js/web && bun install --frozen-lockfile
 
build-assets:                     ## Build frontend into the Python package
	@uv run app assets install
	@uv run app assets build
 
build-wheel: build-assets         ## Self-contained Python wheel
	@uv build --wheel --clear
 
build-onefile: build-wheel        ## Single-file PyApp binary
	@./tools/scripts/build-onefile-package.sh

The dependency chain is load-bearing: build-onefile depends on build-wheel, which depends on build-assets. Running them out of order produces an empty or broken artifact.

The two-variant story

Real projects have multiple JS build outputs that all need to land in the wheel:

js-build-all: js-build-web js-build-offline-report
build-wheel: generate-licenses build-templates js-build-all
	@uv build --wheel --clear

Each js-build-* target emits into a distinct subdirectory of the Python package (src/py/<app>/server/public, src/py/<app>/domain/web/static/reports/offline, etc.). Because they're all inside the package, a single uv build --wheel --clear captures everything.

<workflow>

Workflow

Step 1: Point Vite output inside the Python package

Configure ViteConfig(paths=PathConfig(bundle_dir=Path("app/domain/web/public"))) in Python so .litestar.json bridges the target directory to litestar-vite-plugin. If vite.config.ts overrides build.outDir directly (monorepo or standalone Vite build), set build.outDir and litestar({ bundleDir, hotFile }) to an absolute path inside your Python package (src/py/<pkg>/... or <pkg>/...). Do not let Vite default to ./dist/.

Step 2: Choose a Hatchling bundling strategy

• `force-include` (inertia): List the built-asset directory explicitly under [tool.hatch.build.targets.wheel.force-include]. Built assets stay .gitignored. Explicit, auditable.
• `ignore-vcs = true` (SPA): Tell Hatchling to ignore .gitignore. All package files ship. Simpler; requires discipline to keep dev junk out of package dirs.
• Optional custom Hatchling hook: If you add a BuildHookInterface subclass to run bun run build during uv build, guard initialize(version, build_data) with if version == "editable": return so uv sync does not trigger a frontend build during editable installs.

See references/wheel-assets.md for full config.

Step 3: Wire Makefile targets

Create install, build-assets, build-wheel. Make the wheel target depend on the asset target. Pass --clear to uv build --wheel --clear so stale wheels in dist/ never get picked up by downstream packaging steps.

Step 4: Add PyApp (if shipping a binary)

Decide which flavor:

• Simple: add [tool.hatch.build.targets.binary] to pyproject.toml and run uv run hatch build --target binary. Good when end-users have PyPI access. See pyapp-simple.md.
• Advanced: write a tools/bundler.py that pre-installs deps into a python-build-standalone archive, patches PyApp's src/app.rs for a custom install dir, then runs cargo zigbuild. Good for air-gapped distribution or bespoke install locations. See pyapp-advanced.md.

Step 5: Add GitHub Actions CI

Start with a reusable test.yml that accepts python-version + coverage inputs. Call it from ci.yml across a matrix. Use astral-sh/setup-uv@v7 and oven-sh/setup-bun@v2. See github-ci.md.

For larger projects, factor setup-python and setup-node into .github/actions/ composite actions.

Step 6: Add release workflow

Trigger on v* tags. Run the test matrix first. Then build the wheel once. Then build PyApp onefiles in a per-target matrix (x86_64-unknown-linux-gnu, aarch64-unknown-linux-gnu, Apple, Windows). Upload to gh release create. See github-release.md.

</workflow>

<guardrails>

Guardrails

• Vite/bun output must land inside a Python package directory. Otherwise Hatchling drops it. Set PathConfig.bundle_dir (and any explicit Vite build.outDir) to a path under src/py/<pkg>/ or <pkg>/.
• `uv build` runs last. Assets, licenses, templates, OpenAPI TypeGen all run before uv build --wheel --clear.
• Pick one bundling strategy. force-include or ignore-vcs = true, not both. Mixing them causes duplicate-file warnings and unpredictable wheel contents.
• Skip editable installs in custom Hatchling hooks. If a custom BuildHookInterface runs in pyproject.toml, short-circuit when version == "editable" and exclude the hook directory from mypy/pyright unless hatchling is in the typecheck environment.
• PyApp `PYAPP_*` config vars are build-time, not runtime. PYAPP_PROJECT_NAME, PYAPP_PYTHON_VERSION, PYAPP_DISTRIBUTION_EMBED, PYAPP_DISTRIBUTION_VARIANT_GIL are consumed when cargo build compiles PyApp — not when the resulting binary runs. At runtime, PyApp sets PYAPP=1 (or the executable path when PYAPP_PASS_LOCATION=1) inside the spawned Python process.
• PyApp version upgrades touch multiple files. pyproject.toml, build-onefile-package.sh, .github/workflows/release.yml, tools/bundler.py. See upgrading.md.
• `cargo-zigbuild` for portable glibc. Plain cargo build on a modern Linux runner produces binaries that fail on older distros (glibc too new). Use cargo zigbuild --target x86_64-unknown-linux-gnu.2.17 to link against glibc 2.17 (CentOS 7-era). Required for broad compatibility.
• Static-link native deps in PyApp. Set BZIP2_SYS_STATIC=1 and LZMA_API_STATIC=1 before cargo zigbuild, or patch Cargo.toml to add features = ["static"]. Otherwise the onefile fails to load on systems without matching libbz2.so / liblzma.so.
• Pin `uv` and `bun` versions in CI. Use exact pinned versions (e.g., UV_VERSION=0.11.6 and BUN_INSTALL_VERSION=bun-v1.3.12). Drift in either breaks reproducible builds.
• Create placeholder asset dirs in CI. Hatchling's force-include target fails if app/domain/web/public or src/py/app/server/static/web doesn't exist at wheel/editable-build time. CI jobs that don't build the frontend (lint, mypy, pyright) still need mkdir -p <asset-dir> before uv sync.
• Never commit built frontend output. Keep bundle_dir paths in .gitignore. CI rebuilds them on every run. Reason: JS builds are non-deterministic across machines and cause noisy diffs.
• Coverage on one Python version only. Multiple versions uploading the same coverage.xml silently stomp each other. Pin it to one version in your matrix (if: matrix.python-version == '3.12').
• Disk cleanup on self-hosted runners. GitHub's ubuntu-latest has ~30GB free; building wheels + PyApp + Docker images can blow past that. Aggressive cleanup before the build job is routine.

</guardrails>

<validation>

Validation Checkpoint

Before claiming "the wheel builds":

• [ ] make build-wheel succeeds in a clean checkout (after make install)
• [ ] unzip -l dist/*.whl | grep -E '\.(js|css|html)$' shows the built frontend
• [ ] The wheel installs cleanly (uv pip install dist/*.whl in a fresh venv)
• [ ] python -c "import app; app.run()" (or equivalent) serves assets with no extra steps
• [ ] .gitignore excludes the built asset directory
• [ ] PathConfig.bundle_dir (and any explicit Vite build.outDir) resolves inside a Python package dir
• [ ] Hatchling config uses exactly one of force-include OR ignore-vcs = true

Before claiming "the PyApp binary works":

• [ ] dist/<app> --help runs on the build machine
• [ ] The binary is ≥ 50 MB (much smaller means it's not embedding Python)
• [ ] On Linux, ldd dist/<app> shows ≤ libc / libm / libpthread (no libbz2, no liblzma)
• [ ] A network-isolated docker run --rm --network=none gcr.io/distroless/cc-debian12:nonroot /opt/dist/<app> --help succeeds (proves no runtime PyPI fetches)
• [ ] The install dir (~/.<app>/runtime/ or similar) is created on first run and re-used on second run

Before claiming "CI works":

• [ ] Python matrix covers minimum + stable + latest (e.g., 3.11, 3.12, 3.13)
• [ ] make build-wheel runs in CI and the resulting wheel is uploaded as an artifact
• [ ] Pre-commit / ruff / mypy / pyright / slotscheck run on every PR
• [ ] Release workflow is gated on CI (needs: [lint, test])
• [ ] A tag push produces wheel + onefiles + GitHub release in one run

</validation>

<example>

Example

[build-system]
build-backend = "hatchling.build"
requires = ["hatchling"]
 
[tool.hatch.build.targets.wheel]
packages = ["app"]
 
[tool.hatch.build.targets.wheel.force-include]
"app/domain/web/public" = "app/domain/web/public"
 
[tool.hatch.build.targets.binary]
pyapp-version = "0.29.0"
python-version = "3.13"
scripts = ["app"]
 
[tool.hatch.build.targets.binary.env]
PYAPP_DISTRIBUTION_EMBED = "1"
PYAPP_FULL_ISOLATION = "1"
PYAPP_UV_ENABLED = "1"

Example Projects

• [litestar-fullstack-inertia](https://github.com/litestar-org/litestar-fullstack-inertia) — monolithic app/ layout, Inertia.js + React 19, force-include bundling, hatch build --target binary for 4-platform PyApp.
• [litestar-fullstack](https://github.com/litestar-org/litestar-fullstack) — nested src/py/app/ + src/js/web/ layout, React + TanStack Router SPA, ignore-vcs = true bundling, React Email templates.

</example>

References Index

• Wheel Build + Asset Bundling
• PyApp — Simple (hatch-binary)
• PyApp — Advanced (offline, custom install dir, portable glibc)
• GitHub Actions — CI (Test Matrix)
• GitHub Actions — Release
• Upgrading — Python, PyApp, python-build-standalone

Official References

• <https://ofek.dev/pyapp/> — PyApp documentation (all PYAPP_* env vars)
• <https://github.com/ofek/pyapp> — PyApp source (patch target: src/app.rs)
• <https://hatch.pypa.io/latest/config/build/> — Hatchling build config
• <https://hatch.pypa.io/latest/plugins/builder/binary/> — Hatch binary builder (simple PyApp)
• <https://docs.astral.sh/uv/concepts/projects/build/> — uv build reference
• <https://github.com/astral-sh/python-build-standalone/releases> — Portable Python archives
• <https://github.com/rust-cross/cargo-zigbuild> — cargo-zigbuild for portable glibc
• <https://bun.sh/docs/cli/install> — Bun install and lockfile

Cross-References

• litestar-deployment — runtime deployment (Dockerfiles, K8s, Railway, Cloud Run, systemd) that consumes the artifacts this skill produces
• litestar-vite — Vite plugin config (asset pipeline details, TypeGen, HMR)
• litestar-granian — Granian ASGI server (what the wheel's entry-point starts)
• litestar settings — env-driven @dataclass settings that work both in-wheel and as a PyApp binary

Shared Styleguide Baseline

• General Principles
• Python
• CI/CD
• Litestar