A minimal build backend for uv: uv_build #11446

konstin · 2025-02-12T14:58:24Z

uv itself is a large package with many dependencies and lots of features. To build a package using the uv build backend, you shouldn't have to download and install the entirety of uv. For platform where we don't provide wheels, it should be possible and fast to compile the uv build backend. To that end, we're introducing a python package that contains a trimmed down version of uv that only contains the build backend, with a minimal dependency tree in rust.

The uv_build package is publish from CI just like uv itself. It is part of the workspace, but has much less dependencies for its own binary. We're using cargo deny to enforce that the network stack is not part of the dependencies. A new build profile ensure we're getting the minimum possible binary size for a rust binary.

python/uv/_build_backend.py

We only support `uv_build` as build backend to avoid the duplication and confusion about configuration.

…ckend

Gankra

looked over everything but the python

Gankra · 2025-02-13T13:48:05Z

Cargo.toml

+# Profile for uv-build
+[profile.minimal-size]
+inherits = "release"
+opt-level = "z"
+


panic = "abort" may also reduce size if we're desperate for every byte: https://doc.rust-lang.org/cargo/reference/profiles.html#panic

Probably worth at least checking how much it saves us

I've added it for, it gets us down to 1217927 bytes on linux. I'm not sure with we want to deploy that, we've had very few panics in the past but if the happen the panic message is the only indication we get.

Gankra · 2025-02-13T13:55:02Z

crates/uv-build/src/main.rs

@@ -0,0 +1,92 @@
+#![allow(clippy::print_stdout)]


I would love to have a comment here explaining why we are doing this. just to produce an anyhow error instead of panic when stdout is closed?

I've mostly done it for consistency with writeln!(printer.stdout(), ...) we're using everywhere else, i don't feel strongly about.

Gankra · 2025-02-13T13:56:40Z

crates/uv-build/pyproject.toml

+[build-system]
+requires = ["maturin>=1.0,<2.0"]
+build-backend = "maturin"
+


i don't know why but this is incredibly funny to me (it makes sense)

Gankra · 2025-02-13T13:57:08Z

crates/uv-build/deny.toml

+[bans]
+multiple-versions = "allow"
+deny = [
+  { crate = "rustls", reason = "The build backend does not need network access" },
+  { crate = "openssl", reason = "The build backend does not need network access" },
+  { crate = "reqwest", reason = "The build backend does not need network access" },
+  { crate = "schemars", reason = "JSON Schema generation is a development feature, not a runtime feature" },
+]


Gankra · 2025-02-13T14:00:05Z

.github/workflows/build-binaries.yml

+      # uv-build
+      - name: "Build wheels uv-build - x86_64"
+        uses: PyO3/maturin-action@v1
+        with:
+          target: x86_64
+          args: --profile minimal-size --locked --out crates/uv-build/dist -m crates/uv-build/Cargo.toml
+      - name: "Upload wheels uv-build"
+        uses: actions/upload-artifact@v4
+        with:
+          name: wheels_uv_build-macos-x86_64
+          path: crates/uv-build/dist
+


Hmm I was gonna say this will slow down releases a lot if it's serial but in theory this thing should build super fast so it's fine?

It's 22s on a fresh target directory for me locally. I had initially put them in succession to reuse the target dir, but that mostly doesn't apply anymore with the different opt mode.

Yeah basically nothing to share

T-256

IIUC, to configure backend, we should use tool.uv.build-backend, but since uv_build is now standalone package could expect it to be changed?

IMO, tool.uv.build or tool.uv-build is closer to uv_build, the package name.

T-256 · 2025-02-13T15:16:46Z

python/uv/__init__.py

-if os.environ.get("UV_PREVIEW"):
-    __all__ = [
-        "find_uv_bin",
-        # PEP 517 hook `build_sdist`.
-        "build_sdist",
-        # PEP 517 hook `build_wheel`.
-        "build_wheel",
-        # PEP 660 hook `build_editable`.
-        "build_editable",
-        # PEP 517 hook `get_requires_for_build_sdist`.
-        "get_requires_for_build_sdist",
-        # PEP 517 hook `get_requires_for_build_wheel`.
-        "get_requires_for_build_wheel",
-        # PEP 517 hook `prepare_metadata_for_build_wheel`.
-        "prepare_metadata_for_build_wheel",
-        # PEP 660 hook `get_requires_for_build_editable`.
-        "get_requires_for_build_editable",
-        # PEP 660 hook `prepare_metadata_for_build_editable`.
-        "prepare_metadata_for_build_editable",
-    ]
-else:
-    __all__ = ["find_uv_bin"]


consider either remove or change the message to use uv_build instead.

uv/python/uv/__init__.py

Lines 33 to 46 in a4bd73f

def __getattr__(attr_name: str) -> object:

if attr_name in {

"build_sdist",

"build_wheel",

"build_editable",

"get_requires_for_build_sdist",

"get_requires_for_build_wheel",

"prepare_metadata_for_build_wheel",

"get_requires_for_build_editable",

"prepare_metadata_for_build_editable",

}:

err = f"Using `uv.{attr_name}` is not allowed. The uv build backend requires preview mode to be enabled, e.g., via the `UV_PREVIEW=1` environment variable."

raise AttributeError(err)

konstin force-pushed the konsti/standalone-build-backend-package branch from 5aadae4 to 6123fe0 Compare February 12, 2025 15:20

cthoyt reviewed Feb 12, 2025

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konstin force-pushed the konsti/standalone-build-backend-package branch 5 times, most recently from 72875c8 to 6fff5b2 Compare February 13, 2025 12:46

konstin mentioned this pull request Feb 13, 2025

More consistent build-binaries.yml #11478

Open

konstin added 6 commits February 13, 2025 14:06

Split out uv-build package

b7aa158

Use uv-build as build backend consistently

76b6ba6

Publish uv-build from CI

2aed89e

Remove build backend Python shims from uv

317fcf8

We only support `uv_build` as build backend to avoid the duplication and confusion about configuration.

Use cargo-deny to prevent extra crates being pulled into the build ba…

4a7dc0f

…ckend

Bump version

b62aa08

konstin force-pushed the konsti/standalone-build-backend-package branch from 6fff5b2 to b62aa08 Compare February 13, 2025 13:07

konstin changed the base branch from main to konsti/refactor-build-binaries February 13, 2025 13:07

konstin changed the title ~~CI: uv-build~~ A minimal build backend for uv: uv_build Feb 13, 2025

Gankra reviewed Feb 13, 2025

View reviewed changes

konstin added 2 commits February 13, 2025 15:56

Remove unused clippy allows

9847419

Use panic abort

9c7623f

T-256 reviewed Feb 13, 2025

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A minimal build backend for uv: uv_build #11446

A minimal build backend for uv: uv_build #11446

konstin commented Feb 12, 2025 •

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T-256 Feb 13, 2025

	def __getattr__(attr_name: str) -> object:
	if attr_name in {
	"build_sdist",
	"build_wheel",
	"build_editable",
	"get_requires_for_build_sdist",
	"get_requires_for_build_wheel",
	"prepare_metadata_for_build_wheel",
	"get_requires_for_build_editable",
	"prepare_metadata_for_build_editable",
	}:
	err = f"Using `uv.{attr_name}` is not allowed. The uv build backend requires preview mode to be enabled, e.g., via the `UV_PREVIEW=1` environment variable."
	raise AttributeError(err)

A minimal build backend for uv: uv_build #11446

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konstin commented Feb 12, 2025 • edited Loading

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konstin commented Feb 12, 2025 •

edited

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