Add bootstrap script/wheel module for flit_core

flit_core/bootstrap.py

@@ -0,0 +1,87 @@
+"""Install flit_core without using any other tools.
+
+Normally, you would install flit_core with pip like any other Python package.
+This script is meant to help with 'bootstrapping' other packaging
+systems, where you may need flit_core to build other packaging tools.
+
+Pass a path to the site-packages directory or equivalent where the package
+should be placed. If omitted, this defaults to the site-packages directory
+of the Python running the script.
+"""
+import argparse
+import sys
+import sysconfig
+from pathlib import Path
+from tempfile import TemporaryDirectory
+from zipfile import ZipFile
+
+from flit_core.wheel import add_wheel_arguments, build_flit_wheel
+
+srcdir = Path(__file__).parent.resolve()
+
+def extract_wheel(whl_path, dest):
+    print("Installing to", dest.resolve())
+    with ZipFile(whl_path) as zf:
+        zf.extractall(dest)
+
+def add_install_arguments(parser):
+    parser.add_argument(
+        '--wheeldir',
+        '-w',
+        type=str,
+        help=f'wheel dist directory (defaults to {srcdir.joinpath("dist").resolve()})',
+    )
+    purelib = Path(sysconfig.get_path('purelib'))
+    parser.add_argument(
+        '--installdir',
+        '-i',
+        type=Path,
+        default=purelib,
+        help=f'installdir directory (defaults to {purelib.resolve()}',
+    )
+    return parser
+
+def get_dist_wheel(wheeldir):
+    wheel_path = Path(wheeldir) if wheeldir is not None else srcdir.joinpath('dist')
+    wheel_glob = wheel_path.glob('flit_core-*.whl')
+    return next(wheel_glob, None)
+
+def build(args):
+    print("Building wheel")
+    outdir = srcdir.joinpath('dist') if args.outdir is None else Path(args.outdir)
+    whl_fname = build_flit_wheel(srcdir, outdir)
+    print("Wheel built", outdir.joinpath(whl_fname).resolve())
+
+def install(args):
+    dist_wheel = get_dist_wheel(args.wheeldir)
+
+    # User asked to install wheel but none was found
+    if dist_wheel is None and args.wheeldir is not None:
+        print(f"No wheel found in {Path(args.wheeldir).resolve()}")
+        sys.exit(1)
+
+    if dist_wheel is not None:
+        print("Installing from wheel", dist_wheel.resolve())
+        # Extract the prebuilt wheel
+        extract_wheel(dist_wheel, args.installdir)
+    else:
+        # No prebuilt wheel found, build in temp dir
+        with TemporaryDirectory(prefix='flit_core-bootstrap-') as td:
+            whl_fname = build_flit_wheel(srcdir, Path(td))
+            whl_path = Path(td).joinpath(whl_fname)
+            extract_wheel(whl_path, args.installdir)
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    subparsers = parser.add_subparsers()
+
+    build_parser = subparsers.add_parser('build')
+    build_parser = add_wheel_arguments(build_parser, srcdir)
+    build_parser.set_defaults(func=build)
+
+    install_parser = subparsers.add_parser('install')
+    install_parser = add_install_arguments(install_parser)
+    install_parser.set_defaults(func=install)
+
+    args = parser.parse_args()
+    args.func(args)

flit_core/flit_core/wheel.py

@@ -1,3 +1,4 @@
+import argparse
 from base64 import urlsafe_b64encode
 import contextlib
 from datetime import datetime
@@ -8,6 +9,7 @@
 import os.path as osp
 import stat
 import tempfile
+from pathlib import Path
 from types import SimpleNamespace
 from typing import Optional
 import zipfile
@@ -215,3 +217,40 @@ def make_wheel_in(ini_path, wheel_directory, editable=False):
 
     log.info("Built wheel: %s", wheel_path)
     return SimpleNamespace(builder=wb, file=wheel_path)
+
+def add_wheel_arguments(parser, srcdir=None):
+    if srcdir is None:
+        srcdir = Path.cwd()
+        parser.add_argument(
+            '--srcdir',
+            '-s',
+            type=Path,
+            default=Path.cwd(),
+            help='source directory (defaults to current directory)',
+        )
+
+    parser.add_argument(
+        '--outdir',
+        '-o',
+        type=Path,
+        default=srcdir.joinpath('dist'),
+        help=f'output directory (defaults to {srcdir.joinpath("dist").resolve()})',
+    )
+    return parser
+
+def build_flit_wheel(srcdir, outdir):
+    """Builds a wheel, places it in outdir"""
+    pyproj_toml = Path(srcdir).joinpath('pyproject.toml')
+    outdir.mkdir(parents=True, exist_ok=True)
+    info = make_wheel_in(pyproj_toml, Path(outdir))
+    return info.file.name
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser = add_wheel_arguments(parser)
+    args = parser.parse_args()
+    srcdir = Path.cwd() if args.srcdir is None else Path(args.srcdir)
+    outdir = args.outdir
+    print("Building wheel")
+    whl_fname = build_flit_wheel(srcdir, outdir)
+    print("Wheel built", outdir.joinpath(whl_fname).resolve())

flit_core/pyproject.toml

@@ -19,3 +19,6 @@ dynamic = ["version"]
 
 [project.urls]
 Source = "https://github.com/pypa/flit"
+
+[tool.flit.sdist]
+include = ["bootstrap.py"]