Self contained rust boostrapping

maturin/__init__.py

@@ -65,6 +65,17 @@ def _additional_pep517_args() -> List[str]:
     return []
 
 
+def _get_env() -> Optional[Dict[str, str]]:
+    if not os.environ.get("MATURIN_NO_INSTALL_RUST") and not shutil.which("cargo"):
+        from puccinialin import setup_rust
+
+        print("Rust not found, installing into a temporary directory")
+        extra_env = setup_rust()
+        return {**os.environ, **extra_env}
+    else:
+        return None
+
+
 # noinspection PyUnusedLocal
 def _build_wheel(
     wheel_directory: str,
@@ -97,7 +108,7 @@ def _build_wheel(
 
     print("Running `{}`".format(" ".join(command)))
     sys.stdout.flush()
-    result = subprocess.run(command, stdout=subprocess.PIPE)
+    result = subprocess.run(command, stdout=subprocess.PIPE, env=_get_env())
     sys.stdout.buffer.write(result.stdout)
     sys.stdout.flush()
     if result.returncode != 0:
@@ -125,7 +136,7 @@ def build_sdist(sdist_directory: str, config_settings: Optional[Mapping[str, Any
 
     print("Running `{}`".format(" ".join(command)))
     sys.stdout.flush()
-    result = subprocess.run(command, stdout=subprocess.PIPE)
+    result = subprocess.run(command, stdout=subprocess.PIPE, env=_get_env())
     sys.stdout.buffer.write(result.stdout)
     sys.stdout.flush()
     if result.returncode != 0:
@@ -138,9 +149,12 @@ def build_sdist(sdist_directory: str, config_settings: Optional[Mapping[str, Any
 # noinspection PyUnusedLocal
 def get_requires_for_build_wheel(config_settings: Optional[Mapping[str, Any]] = None) -> List[str]:
     if get_config().get("bindings") == "cffi":
-        return ["cffi"]
+        requirements = ["cffi"]
     else:
-        return []
+        requirements = []
+    if not os.environ.get("MATURIN_NO_INSTALL_RUST") and not shutil.which("cargo"):
+        requirements += ["puccinialin"]
+    return requirements
 
 
 # noinspection PyUnusedLocal
@@ -158,7 +172,10 @@ def build_editable(
 
 # noinspection PyUnusedLocal
 def get_requires_for_build_sdist(config_settings: Optional[Mapping[str, Any]] = None) -> List[str]:
-    return []
+    requirements = []
+    if not os.environ.get("MATURIN_NO_INSTALL_RUST") and not shutil.which("cargo"):
+        requirements += ["puccinialin"]
+    return requirements
 
 
 # noinspection PyUnusedLocal
@@ -168,7 +185,7 @@ def prepare_metadata_for_build_wheel(
     print("Checking for Rust toolchain....")
     is_cargo_installed = False
     try:
-        output = subprocess.check_output(["cargo", "--version"]).decode("utf-8", "ignore")
+        output = subprocess.check_output(["cargo", "--version"], env=_get_env()).decode("utf-8", "ignore")
         if "cargo" in output:
             is_cargo_installed = True
     except (FileNotFoundError, SubprocessError):
@@ -200,7 +217,7 @@ def prepare_metadata_for_build_wheel(
 
     print("Running `{}`".format(" ".join(command)))
     try:
-        _output = subprocess.check_output(command)
+        _output = subprocess.check_output(command, env=_get_env())
     except subprocess.CalledProcessError as e:
         sys.stderr.write(f"Error running maturin: {e}\n")
         sys.exit(1)

maturin/boostrap.py

@@ -0,0 +1,31 @@
+"""Support installing rust before compiling (bootstrapping) maturin.
+
+Installing a package that uses maturin as build backend on a platform without maturin
+binaries, we install rust in a cache directory if the user doesn't have a rust
+installation already. Since this bootstrapping requires more dependencies but is only
+required if rust is missing, we check if cargo is present before requesting those
+dependencies.
+
+https://setuptools.pypa.io/en/stable/build_meta.html#dynamic-build-dependencies-and-other-build-meta-tweaks
+"""
+
+from __future__ import annotations
+
+import os
+import shutil
+from typing import Any
+
+# noinspection PyUnresolvedReferences
+from setuptools.build_meta import *  # noqa:F403
+
+
+def get_requires_for_build_wheel(_config_settings: dict[str, Any] | None = None) -> list[str]:
+    if not os.environ.get("MATURIN_NO_INSTALL_RUST") and not shutil.which("cargo"):
+        return ["puccinialin>=0.1,<0.2"]
+    return []
+
+
+def get_requires_for_build_sdist(_config_settings: dict[str, Any] | None = None) -> list[str]:
+    if not os.environ.get("MATURIN_NO_INSTALL_RUST") and not shutil.which("cargo"):
+        return ["puccinialin>=0.1,<0.2"]
+    return []

pyproject.toml

@@ -1,15 +1,16 @@
 # Workaround to bootstrap maturin on non-manylinux platforms
 [build-system]
-requires = ["setuptools", "wheel>=0.36.2", "tomli>=1.1.0 ; python_version<'3.11'", "setuptools-rust>=1.4.0"]
-build-backend = "setuptools.build_meta"
+requires = ["setuptools", "tomli>=1.1.0 ; python_version<'3.11'", "setuptools-rust @ git+https://github.com/PyO3/setuptools-rust@konsti/add-custom-env-vars"]
+backend-path = ["maturin"]
+build-backend = "boostrap"
 
 [project]
 name = "maturin"
 description = "Build and publish crates with pyo3, cffi and uniffi bindings as well as rust binaries as python packages"
 authors = [{ name = "konstin", email = "[email protected]" }]
 readme = { file = "README.md", content-type = "text/markdown" }
 requires-python = ">=3.7"
-license = {text = "MIT OR Apache-2.0"}
+license = { text = "MIT OR Apache-2.0" }
 classifiers = [
     "Topic :: Software Development :: Build Tools",
     "Programming Language :: Rust",

setup.py

@@ -11,6 +11,7 @@
 
 import os
 import shlex
+import shutil
 
 try:
     import tomllib
@@ -47,9 +48,18 @@ def finalize_options(self):
 if os.getenv("MATURIN_SETUP_ARGS"):
     cargo_args = shlex.split(os.getenv("MATURIN_SETUP_ARGS", ""))
 
+if not os.environ.get("MATURIN_NO_INSTALL_RUST") and not shutil.which("cargo"):
+    from puccinialin import setup_rust
+
+    print("Rust not found, installing into a temporary directory")
+    extra_env = setup_rust()
+    env = {**os.environ, **extra_env}
+else:
+    env = None
+
 setup(
     version=version,
     cmdclass={"bdist_wheel": bdist_wheel},
-    rust_extensions=[RustBin("maturin", args=cargo_args, cargo_manifest_args=["--locked"])],
+    rust_extensions=[RustBin("maturin", args=cargo_args, cargo_manifest_args=["--locked"], env=env)],
     zip_safe=False,
 )