Cython bundling

Bundling a Cython program using pyinstaller

Start from a Cython program with a entrypoint:

def do_stuff():
    cdef int a,b,c
    a = 1
    b = 2
    c = 3
    print("Hello World!")
    print([a,b,c])
    input("Press Enter to continue.")

Create a setup.py file in the same folder:

from distutils.core import setup
from Cython.Build import cythonize
setup(
    name = "Hello World",
    ext_modules = cythonize('program.pyx'), 
)

Running it with python setup.py build_ext --inplace will produce a .pyd library in a subfolder.

After that, create a vanilla Python script using the library (e.g., main.py) and put the .pyd file beside it:

import program
program.do_stuff()

Use PyInstaller to bundle it pyinstaller --onefile "main.py". This will create a subfolder containing the executable of a 4 MB+ size containing the library plus the python runtime.

Automating build (Windows)

For automation of the above procedure in Windows use a .bat of the similar contents:

del "main.exe"
python setup.py build_ext --inplace
del "*.c"
rmdir /s /q ".\build"
pyinstaller --onefile "main.py"
copy /y ".\dist\main.exe" ".\main.exe"
rmdir /s /q ".\dist"
rmdir /s /q ".\build"
del "*.spec"
del "*.pyd"

Adding Numpy to the bundle

To add Numpy to the bundle, modify the setup.py with include_dirs keyword and necessary import the numpy in the wrapper Python script to notify Pyinstaller.

program.pyx:

import numpy as np
cimport numpy as np


def do_stuff():
    print("Hello World!")
    cdef int n
    n = 2
    r = np.random.randint(1,5)
    print("A random number: "+str(r))
    print("A random number multiplied by 2 (made by cdef):"+str(r*n))
    input("Press Enter to continue.")

setup.py:

from distutils.core import setup, Extension
from Cython.Build import cythonize
import numpy

setup(
    ext_modules=cythonize("hello.pyx"),
    include_dirs=[numpy.get_include()]
)

main.py:

import program
import numpy
program.do_stuff()