gn-dist

Binary distributions of GN (generate-ninja) for Linux (glibc and musl).

Other systems are out of scope for this project. For Windows and macOS builds, please refer to Google CIPD.

Installation

python3 -m pip install gn-dist

# convenience wrapper script
GN_WRAPPER=$(which gn)
$GN_WRAPPER --version

# actual binary
GN_EXE=$(python3 -c "from gn_dist import GN; print(str(GN))")
$GN_EXE --version

# to add the actual binary to PATH, you can do e.g.:
GN_DIR="$(dirname $GN_EXE)"  # or use GN.parent above
export PATH="$GN_DIR:$PATH"
# ^ add this to your ~/.bashrc if you want

Building

./build_gn.py automates the build process (run with --help for options, as usual).

gn-dist's setup implies building GN. Run e.g. pip install -v . or pyproject-build -wxn.
Set $BUILD_PARAMS to pass options to build_gn.py through the setup layer.

Versioning

gn-dist (and GN itself) use git to infer version info.

This is known to cause issues with shallow checkouts. We recommend that you configure your clone of gn-dist in a way that allows git describe to do its job.

Where that is not possible (e.g. when installing from a tarball that does not contain the git repository), a src/gn_dist/VERSION file must be provided.
This is just a plain text file containing the version string that will be passed to gn-dist's PEP 517 build backend. The version should be provided as a PEP 440 / PyPA specs compatible normalization of what would otherwise be returned by git describe.
The VERSION file is included in sdists and will be auto-generated where possible.

GN checkout is typically managed by gn-dist itself (which does a full clone), but if you insist on bringing your own copy of GN, you may need to provide a //out/last_commit_position.h file (relative to //sbuild/gn), in the following format:

#ifndef OUT_LAST_COMMIT_POSITION_H_
#define OUT_LAST_COMMIT_POSITION_H_

#define LAST_COMMIT_POSITION_NUM %(num)s
#define LAST_COMMIT_POSITION "%(num)s (%(commit_id)s)"

#endif  // OUT_LAST_COMMIT_POSITION_H_

where %(num)s is the commit number (counted from the initial commit), and %(commit_id)s the commit hash (truncated to the first 12 digits), as in

git describe HEAD --abbrev=12 --match initial-commit

Then edit build_gn.py to pass --no-last-commit-position to GN's build/gen.py.

Containerization

To manually build gn-dist in a manylinux2014 container, you can do e.g.:

docker run -v "${PWD}:/projects/gn-dist" --security-opt label=disable -it quay.io/pypa/manylinux2014_x86_64 bash

# this would test python 3.6 compatibility - to use a contemporary version of python, comment in the lines below instead
yum install -y python3
#manylinux-interpreters ensure cp314-cp314
#export PATH="/opt/python/cp314-cp314/bin:${PATH}"
manylinux-install-clang -v latest
python3 -m venv /projects/.venv
export PATH="$/projects/.venv/bin:${PATH}"
python3 -m pip install -U pip
python3 -m pip install -U setuptools wheel build auditwheel
python3 -m pip install -U ninja  # scikit-build/ninja-python-distributions
cd /projects/gn-dist
./build_gn.py --help  # informational
BUILD_PARAMS="-c clang --clang-path /opt/clang" python3 -m build -wxn
#auditwheel repair dist/gn_dist-*.whl

Updating (for maintainers)

To make a new release, first update the GN_REV in build_gn.py and rebuild locally.
Commit and push the changes. Then, assuming an editable install, run gn --version to determine the new version, and create a matching tag (add a minor cipher if it's a rebuild):

git tag -a VERSION -m "Release"

Once you're positive, push the tag. For maintainer convenience, pushing a tag that points to the HEAD of main will automatically trigger the build workflow with publish options enabled.

Once a release has been successfully published to GitHub, tag protection from immutable releases will lock the tag in place. However, if anything goes wrong before that, you may just revoke the tag as usual:

git tag -d VERSION
git push --delete origin VERSION

Then you can fix things up and eventually re-create the tag on another commit.

History

See below for some background why gn-dist was created:

• https://groups.google.com/g/pdfium/c/1__HW-wzJ8c/m/5MCYXAuDBQAJ
• https://chromium-review.googlesource.com/c/chromium/src/+/7593779/comments/fdd2633a_eb123349
• https://gn.googlesource.com/gn/+/88604adbcec2101f25b2e3ebd7f39b38163a6a33/README.md#versioning-and-distribution

Related work

If you are looking for PyPI builds of ninja, scikit-build/ninja-python-distributions is somewhat equivalent to this project. Note though, it uses Kitware's fork of ninja, not the original version.

There is also loong64/gn, but for some reason refers to a little-known fork of GN, is not regularly updated, does not include musllinux builds, and is not Python packaged.