gen-dockerfiles

#!/usr/bin/env python3

import os
from urllib import request

RUST_VERSION     =  '1.75.0'
RUSTUP_VERSION   =  '1.26.0'

DISTRIBUTIONS = {
    # Ubuntu
    'bionic': 'x86_64-unknown-linux-gnu',
    # CentOS
    'centos-7': 'x86_64-unknown-linux-gnu',
    # Arch64
    'aarch64': 'aarch64-unknown-linux-gnu',
}


def fetch_rustup_hash(RUST_ARCH):
    url = f'https://static.rust-lang.org/rustup/archive/{RUSTUP_VERSION}/{RUST_ARCH}/rustup-init.sha256'
    with request.urlopen(url) as f:
        return f.read().decode('utf-8').split()[0]


def load_template(dist):
    with open(f'templates/{dist}.Dockerfile', 'r') as f:
        return f.read()

def save_dockerfile(dist, contents):
    filepath = f'{dist}/Dockerfile'
    filedir = os.path.dirname(filepath)
    if filedir and not os.path.exists(filedir):
        os.makedirs(filedir)
    with open(filepath, 'w') as f:
        f.write(contents)

def generate_dockerfile(dist, rustup_sha256, RUST_ARCH):
    template = load_template(dist)
    rendered = template \
        .replace('%%RUST_VERSION%%', RUST_VERSION) \
        .replace('%%RUSTUP_VERSION%%', RUSTUP_VERSION) \
        .replace('%%RUSTUP_SHA256%%', rustup_sha256) \
        .replace('%%RUST_ARCH%%', RUST_ARCH)
    save_dockerfile(dist, rendered)


def main():
    for dist, arch in DISTRIBUTIONS.items():
        rustup_sha256 = fetch_rustup_hash(arch)
        generate_dockerfile(dist, rustup_sha256, arch)


if __name__ == '__main__':
    main()