make_single_executable.sh

#!/usr/bin/env bash

set -x # Print command traces before executing command

set -e # Exit immediately if a simple command exits with a non-zero status.

set -o pipefail # Return value of a pipeline as the value of the last command to
                # exit with a non-zero status, or zero if all commands in the
                # pipeline exit successfully.

# directory containing setup.py and project files
PROJDIR=`pwd`
PROJNAME='mcpartools'

#make single file executable with given name, for given entrypoint
make_zipapp() {

    EXENAME=$1
    ENTRYPOINT=$2

    # temporary dir, convenient for packaging
    TMPDIR=`mktemp -d`

    # make directory, named the same way as the single executable we want to create
    mkdir -p $TMPDIR/$EXENAME

    # wheel package contains all module sources (and extracted version)
    # we will unpack it and use as core code for single executable
    WHEEL_FILE=$(find dist/ -name "$PROJNAME-*.whl" | head -n 1)
    if [ -z "$WHEEL_FILE" ]; then
        echo "Error: Wheel file not found in dist/. Please ensure 'python -m build --wheel .' has run."
        exit 1
    fi

    unzip -q "$WHEEL_FILE" -d "$TMPDIR/$EXENAME"

    # go to TMPDIR
    cd $TMPDIR

    # use zipapp module to make a single executable zip file
    # zipapp was introduced in Python 3.5: https://docs.python.org/3/library/zipapp.html
    # files generated by zipapp can be executed by all Python versions greater than 2.6
    # zipapp will generate __main__.py file in $EXENAME directory
    python3 -m zipapp $EXENAME -p "/usr/bin/env python3" -m $ENTRYPOINT

    # add executable bits
    chmod ugo+x $EXENAME.pyz

    # copy back to project dir
    cp $EXENAME.pyz $PROJDIR
    cd -
}

test_zipapp() {
    # temporary dir, convenient for packaging
    TMPDIR=`mktemp -d`

    # packaged app
    APPFILE=$1

    # copy app to temp dir
    cp -r $APPFILE $TMPDIR

    # go to TMPDIR
    cd $TMPDIR

    echo "--- Testing $(basename "$APPFILE") --version ---"
    ./$(basename "$APPFILE") --version || { echo "Error: --version failed for $(basename "$APPFILE")"; exit 1; }

    echo "--- Testing $(basename "$APPFILE") --help ---"
    ./$(basename "$APPFILE") --help || { echo "Error: --help failed for $(basename "$APPFILE")"; exit 1; }

    # go back
    cd -
}

# --- Main Script Execution ---

echo "--- Building wheel package for zipapp ---"
# Use the 'build' module to generate wheel based on pyproject.toml
# This replaces 'python3 setup.py bdist_wheel'
# Ensure 'build' is installed in the environment where this script runs.
python3 -m build --wheel .

# check if wheels are generated
echo "--- Checking generated wheels ---"
ls -al dist/*.whl || { echo "Error: No wheel files found in dist/"; exit 1; }

# make single executable called generatemc.pyz:
# - containing modules from wheel package
# - executing mcpartools.generatemc:main function
echo "--- Creating generatemc.pyz executable (zipapp) ---"
make_zipapp 'generatemc' 'mcpartools.generatemc:main'

# check if single executable can be called
echo "--- Testing generatemc.pyz executable ---"
test_zipapp "$PROJDIR/generatemc.pyz"

echo "--- Zipapp creation and testing complete ---"