snapdevbuild

#!/usr/bin/env python3

import argparse
import subprocess
import os
import os.path
import logging
import shutil
import shlex


DESTDIR = os.getenv("DESTDIR", "")
STATIC_BUILD_FLAGS = "-buildmode=pie -ldflags='-extldflags=-static'"
BINDIR = "/usr/bin"
LIBEXECDIR = "/usr/lib/snapd"
DIRS = {
    "snap": BINDIR
    # the rest goes to libexecdir
}
FLAGS = {
    "snap-exec": STATIC_BUILD_FLAGS,
    "snap-bootstrap": STATIC_BUILD_FLAGS,
    # the rest has no flags
}
TAGS = {
    "snap": "-tags 'nomanagers nosecboot'"
    # the rest has no tags
}


def pre_action(what):
    if what == "snapd" and not DESTDIR:
        logging.debug("stopping snapd service")
        subprocess.run(shlex.split("sudo systemctl stop snapd"), check=True)


def post_action(what):
    if what == "snapd" and not DESTDIR:
        logging.debug("starting snapd service")
        subprocess.run(shlex.split("sudo systemctl start snapd"), check=True)


def parse_arguments():
    parser = argparse.ArgumentParser(description="build helper")
    parser.add_argument("-b", "--just-build", action="store_true", help="just build")
    parser.add_argument("what", help="binary to build")
    return parser.parse_known_args()


def main(opts, rest):
    test_bin = "test-" + opts.what
    cmd = "go build {flags} {tags} {rest} -o {output} github.com/snapcore/snapd/cmd/{cmd}".format(
        flags=FLAGS.get(opts.what, ""),
        tags=TAGS.get(opts.what, ""),
        output=test_bin,
        cmd=opts.what,
        rest=" ".join(rest),
    )

    logging.debug('running "%s"', cmd)
    subprocess.run(shlex.split(cmd), check=True)

    sz = os.path.getsize(test_bin)
    logging.debug("binary size: %.2f kB", sz / 1024.0)
    if opts.just_build:
        logging.debug("skipping installation")
        return

    # install
    pre_action(opts.what)

    dst = os.path.join(DIRS.get(opts.what, LIBEXECDIR), opts.what)
    if DESTDIR:
        logging.debug('DESTDIR set to %s', DESTDIR)
        dst = os.path.join(DESTDIR, os.path.relpath(dst, start='/'))
    logging.debug('destination: %s', dst)
    subprocess.run(
        shlex.split("sudo cp -v {src} {dst}".format(src=test_bin, dst=dst)), check=True
    )

    post_action(opts.what)


if __name__ == "__main__":
    opts, rest = parse_arguments()
    logging.basicConfig(level=logging.DEBUG, format="%(asctime)s %(message)s")
    main(opts, rest)