Add initial support for uv

.github/workflows/main.yml

@@ -10,6 +10,9 @@ concurrency:
 
 env:
   FORCE_COLOR: 3
+  # Increase this value to reset cache if emscripten_version has not changed
+  EMSDK_CACHE_FOLDER: 'emsdk-cache'
+  EMSDK_CACHE_NUMBER: 0
 
 jobs:
   test:
@@ -89,7 +92,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        task: [test-recipe, test-src, test-integration-marker]
+        task: [
+          {name: test-recipe, installer: pip},
+          {name: test-src, installer: pip},
+          {name: test-recipe, installer: uv},
+          {name: test-src, installer: uv},
+          {name: test-integration-marker, installer: pip},  # installer doesn't matter
+        ]
         os: [ubuntu-latest, macos-latest]
     if: needs.check-integration-test-trigger.outputs.run-integration-test
     steps:
@@ -111,36 +120,47 @@ jobs:
       - name: Install the package
         run: |
           python -m pip install --upgrade pip
-          python -m pip install -e ."[test]"
+          python -m pip install -e ."[test,uv]"
 
       - name: Install xbuildenv
         run: |
           pyodide xbuildenv install
           echo EMSCRIPTEN_VERSION=$(pyodide config get emscripten_version) >> $GITHUB_ENV
 
+      - name: Cache emsdk
+        uses: actions/cache@v4
+        with:
+          path: ${{ env.EMSDK_CACHE_FOLDER }}
+          key: ${{ env.EMSDK_CACHE_NUMBER }}-${{ env.EMSCRIPTEN_VERSION }}-${{ runner.os }}
+
       - name: Install Emscripten
         uses: mymindstorm/setup-emsdk@6ab9eb1bda2574c4ddb79809fc9247783eaf9021 # v14
         with:
           version: ${{ env.EMSCRIPTEN_VERSION }}
+          actions-cache-folder: ${{env.EMSDK_CACHE_FOLDER}}
 
       - name: Get number of cores on the runner
         id: get-cores
         run: echo "CORES=$(nproc)" >> $GITHUB_OUTPUT
 
       - name: Run tests marked with integration
-        if: matrix.task == 'test-integration-marker'
+        if: matrix.task.name == 'test-integration-marker'
         run: pytest --junitxml=test-results/junit.xml --cov=pyodide-build pyodide_build -m "integration"
 
       - name: Run the recipe integration tests (${{ matrix.task }})
-        if: matrix.task != 'test-integration-marker'
+        if: matrix.task.name != 'test-integration-marker'
         env:
           PYODIDE_JOBS: ${{ steps.get-cores.outputs.CORES }}
         working-directory: integration_tests
-        run: make ${{ matrix.task }}
+        run: |
+          if [[ "${{ matrix.task.installer }}" == "uv" ]]; then
+            export UV_RUN_PREFIX="uv run"
+          fi
+          make ${{ matrix.task.name }}
 
       - name: Upload coverage for tests marked with integration
         uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        if: matrix.task == 'test-integration-marker'
+        if: matrix.task.name == 'test-integration-marker'
         with:
           name: coverage-from-integration-${{ matrix.os }}
           path: .coverage

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Added
+
+- Added basic support for uv. `uv tool install pyodide-cli --with pyodide-build`, or `uvx --from pyodide-cli --with pyodide-build pyodide --help`, or using `pyodide-build` in `uv`-managed virtual environments will now work.
+  [#132](https://github.com/pyodide/pyodide-build/pull/132)
+
 ### Changed
 
 - The Rust toolchain version has been updated to `nightly-2025-01-18`.

integration_tests/Makefile

@@ -6,7 +6,7 @@ all:
 test-recipe: check
 	@echo "... Running integration tests for building recipes"
 
-	pyodide build-recipes --recipe-dir=recipes --install --force-rebuild "*"
+	$(UV_RUN_PREFIX) pyodide build-recipes --recipe-dir=recipes --install --force-rebuild "*"
 
 	@echo "... Passed"
 

integration_tests/src/numpy.sh

@@ -10,4 +10,4 @@ tar -xf numpy-${VERSION}.tar.gz
 cd numpy-${VERSION}
 
 MESON_CROSS_FILE=$(pyodide config get meson_cross_file)
-pyodide build -Csetup-args=-Dallow-noblas=true -Csetup-args=--cross-file="${MESON_CROSS_FILE}"
+${UV_RUN_PREFIX} pyodide build -Csetup-args=-Dallow-noblas=true -Csetup-args=--cross-file="${MESON_CROSS_FILE}"

pyodide_build/pypabuild.py

@@ -15,7 +15,7 @@
 from build.env import DefaultIsolatedEnv
 from packaging.requirements import Requirement
 
-from pyodide_build import _f2c_fixes, common, pywasmcross
+from pyodide_build import _f2c_fixes, common, pywasmcross, uv_helper
 from pyodide_build.build_env import (
     get_build_flag,
     get_hostsitepackages,
@@ -149,7 +149,8 @@ def _build_in_isolated_env(
     # It will be left in the /tmp folder and can be inspected or entered as
     # needed.
     # _DefaultIsolatedEnv.__exit__ = lambda self, *args: print("Skipping removing isolated env in", self.path)
-    with _DefaultIsolatedEnv() as env:
+    installer = "uv" if uv_helper.should_use_uv() else "pip"
+    with _DefaultIsolatedEnv(installer=installer) as env:
         env = cast(_DefaultIsolatedEnv, env)
         builder = _ProjectBuilder.from_isolated_env(
             env,

pyodide_build/recipe/graph_builder.py

@@ -27,7 +27,7 @@
 from rich.spinner import Spinner
 from rich.table import Table
 
-from pyodide_build import build_env
+from pyodide_build import build_env, uv_helper
 from pyodide_build.build_env import BuildArgs
 from pyodide_build.common import (
     download_and_unpack_archive,
@@ -130,8 +130,12 @@ def needs_rebuild(self, build_dir: Path) -> bool:
         return res
 
     def build(self, build_args: BuildArgs, build_dir: Path) -> None:
+        run_prefix = (
+            [uv_helper.find_uv_bin(), "run"] if uv_helper.should_use_uv() else []
+        )
         p = subprocess.run(
             [
+                *run_prefix,
                 "pyodide",
                 "build-recipes-no-deps",
                 self.name,

pyodide_build/tests/test_xbuildenv.py

@@ -16,7 +16,7 @@ def monkeypatch_subprocess_run_pip(monkeypatch):
     orig_run = subprocess.run
 
     def monkeypatch_func(cmds, *args, **kwargs):
-        if cmds[0] == "pip":
+        if cmds[0] == "pip" or cmds[0:3] == [sys.executable, "-m", "pip"]:
             called_with.extend(cmds)
             return subprocess.CompletedProcess(cmds, 0, "", "")
         else:
@@ -289,12 +289,20 @@ def test_install_cross_build_packages(
         xbuildenv_pyodide_root = xbuildenv_root / "pyodide-root"
         manager._install_cross_build_packages(xbuildenv_root, xbuildenv_pyodide_root)
 
-        assert len(pip_called_with) == 7
-        assert pip_called_with[0:4] == ["pip", "install", "--no-user", "-t"]
-        assert pip_called_with[4].startswith(
+        assert len(pip_called_with) == 9
+        assert pip_called_with[0:8] == [
+            sys.executable,
+            "-m",
+            "pip",
+            "install",
+            "--no-user",
+            "-r",
+            str(xbuildenv_root / "requirements.txt"),
+            "--target",
+        ]
+        assert pip_called_with[8].startswith(
             str(xbuildenv_pyodide_root)
         )  # hostsitepackages
-        assert pip_called_with[5:7] == ["-r", str(xbuildenv_root / "requirements.txt")]
 
         hostsitepackages = manager._host_site_packages_dir(xbuildenv_pyodide_root)
         assert hostsitepackages.exists()

pyodide_build/uv_helper.py

@@ -0,0 +1,28 @@
+import functools
+import os
+import shutil
+
+
+@functools.cache
+def find_uv_bin() -> str | None:
+    """
+    Check if the uv executable is available.
+
+    If the uv executable is available, return the path to the executable.
+    Otherwise, return None.
+    """
+    try:
+        import uv
+
+        return uv.find_uv_bin()
+    except (ModuleNotFoundError, FileNotFoundError):
+        return shutil.which("uv")
+
+    return None
+
+
+def should_use_uv() -> bool:
+    # UV environ is set to the uv executable path when the script is called with the uv executable.
+    uv_environ = os.environ.get("UV")
+    # double check by comparing the uv executable path with the one found by the uv package.
+    return uv_environ and uv_environ == find_uv_bin()

pyodide_build/xbuildenv.py

@@ -1,11 +1,12 @@
 import json
 import shutil
 import subprocess
+import sys
 from pathlib import Path
 
 from pyodide_lock import PyodideLockSpec
 
-from pyodide_build import build_env
+from pyodide_build import build_env, uv_helper
 from pyodide_build.common import download_and_unpack_archive
 from pyodide_build.create_package_index import create_package_index
 from pyodide_build.logger import logger
@@ -284,15 +285,30 @@ def _install_cross_build_packages(
         """
         host_site_packages = self._host_site_packages_dir(xbuildenv_pyodide_root)
         host_site_packages.mkdir(exist_ok=True, parents=True)
-        result = subprocess.run(
+
+        install_prefix = (
             [
+                uv_helper.find_uv_bin(),
+                "pip",
+                "install",
+            ]
+            if uv_helper.should_use_uv()
+            else [
+                sys.executable,
+                "-m",
                 "pip",
                 "install",
                 "--no-user",
-                "-t",
-                str(host_site_packages),
+            ]
+        )
+
+        result = subprocess.run(
+            [
+                *install_prefix,
                 "-r",
                 str(xbuildenv_root / "requirements.txt"),
+                "--target",
+                str(host_site_packages),
             ],
             capture_output=True,
             encoding="utf8",

pyproject.toml

@@ -63,6 +63,9 @@ test = [
     "pytest-cov",
     "types-requests",
 ]
+uv = [
+  "build[uv]~=1.2.0",
+]
 
 [tool.hatch.version]
 source = "vcs"