view contrib/packaging/hg-docker @ 44413:4cabeea6d214

hgext: start building a library for simple hooks

Many workflows depend on hooks to enforce certain policies, e.g. to
prevent forced pushes. The Mercurial Guide includes some cases and
Google can help finding others, but it can save users a lot of time
if hg itself has a couple of examples for further customization.

Differential Revision: https://phab.mercurial-scm.org/D6825

#!/usr/bin/env python3
#
# Copyright 2018 Gregory Szorc <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

import argparse
import pathlib
import shutil
import subprocess
import sys


def get_docker() -> str:
    docker = shutil.which('docker.io') or shutil.which('docker')
    if not docker:
        print('could not find docker executable')
        return 1

    try:
        out = subprocess.check_output([docker, '-h'], stderr=subprocess.STDOUT)

        if b'Jansens' in out:
            print(
                '%s is the Docking System Tray; try installing docker.io'
                % docker
            )
            sys.exit(1)
    except subprocess.CalledProcessError as e:
        print('error calling `%s -h`: %s' % (docker, e.output))
        sys.exit(1)

    out = subprocess.check_output([docker, 'version'], stderr=subprocess.STDOUT)

    lines = out.splitlines()
    if not any(l.startswith((b'Client:', b'Client version:')) for l in lines):
        print('`%s version` does not look like Docker' % docker)
        sys.exit(1)

    if not any(l.startswith((b'Server:', b'Server version:')) for l in lines):
        print('`%s version` does not look like Docker' % docker)
        sys.exit(1)

    return docker


def get_dockerfile(path: pathlib.Path, args: list) -> bytes:
    with path.open('rb') as fh:
        df = fh.read()

    for k, v in args:
        df = df.replace(bytes('%%%s%%' % k.decode(), 'utf-8'), v)

    return df


def build_docker_image(dockerfile: pathlib.Path, params: list, tag: str):
    """Build a Docker image from a templatized Dockerfile."""
    docker = get_docker()

    dockerfile_path = pathlib.Path(dockerfile)

    dockerfile = get_dockerfile(dockerfile_path, params)

    print('building Dockerfile:')
    print(dockerfile.decode('utf-8', 'replace'))

    args = [
        docker,
        'build',
        '--build-arg',
        'http_proxy',
        '--build-arg',
        'https_proxy',
        '--tag',
        tag,
        '-',
    ]

    print('executing: %r' % args)
    p = subprocess.Popen(args, stdin=subprocess.PIPE)
    p.communicate(input=dockerfile)
    if p.returncode:
        raise subprocess.CalledProcessException(
            p.returncode,
            'failed to build docker image: %s %s' % (p.stdout, p.stderr),
        )


def command_build(args):
    build_args = []
    for arg in args.build_arg:
        k, v = arg.split('=', 1)
        build_args.append((k.encode('utf-8'), v.encode('utf-8')))

    build_docker_image(pathlib.Path(args.dockerfile), build_args, args.tag)


def command_docker(args):
    print(get_docker())


def main() -> int:
    parser = argparse.ArgumentParser()

    subparsers = parser.add_subparsers(title='subcommands')

    build = subparsers.add_parser('build', help='Build a Docker image')
    build.set_defaults(func=command_build)
    build.add_argument(
        '--build-arg',
        action='append',
        default=[],
        help='Substitution to perform in Dockerfile; ' 'format: key=value',
    )
    build.add_argument('dockerfile', help='path to Dockerfile to use')
    build.add_argument('tag', help='Tag to apply to created image')

    docker = subparsers.add_parser('docker-path', help='Resolve path to Docker')
    docker.set_defaults(func=command_docker)

    args = parser.parse_args()

    return args.func(args)


if __name__ == '__main__':
    sys.exit(main())