setuptools-golang

A setuptools extension for building cpython extensions written in golang.

Requirements

This requires golang >= 1.5. It is currently tested against 1.16 and 1.17.

This requires python >= 3.6. It is currently tested against python3 and pypy3.

Platform Support

• linux
• macOS
• win32 (32 bit cpython, 32 bit go 1.10+)

Usage

Add setuptools-golang to the setup_requires in your setup.py and build_golang={'root': ...}. root refers to the root go import path of your project.

By default, setuptools-golang will strip all binaries. This can be disabled by adding 'strip': False to build_golang. This will increase the size of the extension, but the binaries contain debugging information and symbols.

An extension must be a single file in the main go package (though the entire main package will be built into the extension). That package may import other code. You may have multiple extensions in your setup.py.

setup(
    ...
    build_golang={'root': 'github.com/user/project'},
    ext_modules=[Extension('example', ['example.go'])],
    setup_requires=['setuptools-golang'],
    ...
)

Writing cpython extensions in golang

Here's some examples

Common issues

undefined reference to `some_c_function'

Extension by default will bring along the go files listed, but won't bring along the related C files. Add the following to MANIFEST.in:

global-include *.c
global-include *.go

fatal: could not read Username for 'https://github.com':

You're probably trying to import from an external source which does not exist. Double check that your import is correct.

package github.com/a/b/c: /tmp/.../github.com/a/b exists but /tmp/.../github.com/a/b/.git does not - stale checkout?

You've probably mistyped an import. Double check that your import is correct.

duplicate symbol _XXX in: _cgo_export.o mod.cgo2.o

For example:

# github.com/asottile/dockerfile/pylib
duplicate symbol _PyDockerfile_GoParseError in:
    $WORK/github.com/asottile/dockerfile/pylib/_obj/_cgo_export.o
    $WORK/github.com/asottile/dockerfile/pylib/_obj/main.cgo2.o

Make sure to mark global variables defined in C as extern. Here's an example PR

repeated rebuilds can be slow

setuptools-golang attempts to make builds more repeatable by using a separate GOPATH -- if you'd like to reuse a GOPATH you can set the SETUPTOOLS_GOLANG_GOPATH environment variable:

$ SETUPTOOLS_GOLANG_GOPATH=~/go pip install .
...

Building manylinux wheels

setuptools-golang also provides a tool for building PEP 513 manylinux1 wheels so your consumers don't need to have a go compiler installed to use your library.

Simply run setuptools-golang-build-manylinux-wheels from your source directory. The resulting wheels will end up in ./dist.

$ setuptools-golang-build-manylinux-wheels

...

+ ls /dist -al
total 8092
drwxrwxr-x  2 1000 1000    4096 Feb  1 04:16 .
drwxr-xr-x 41 root root    4096 Feb  1 04:15 ..
-rw-r--r--  1 1000 1000 2063299 Feb  1 04:16 setuptools_golang_examples-0.1.1-cp34-cp34m-manylinux1_x86_64.whl
-rw-r--r--  1 1000 1000 2064862 Feb  1 04:16 setuptools_golang_examples-0.1.1-cp35-cp35m-manylinux1_x86_64.whl
-rw-r--r--  1 1000 1000 2064873 Feb  1 04:16 setuptools_golang_examples-0.1.1-cp36-cp36m-manylinux1_x86_64.whl
-rw-rw-r--  1 1000 1000    4273 Feb  1 04:14 setuptools-golang-examples-0.1.1.tar.gz
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Your wheels have been built into ./dist
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