update-service

#!/usr/bin/env python3

# Standalone executable for running the TinyPilot updater and saving the result
# to a file. This executable is meant to be run as a systemd one-shot service,
# launched manually when the user requests an update.

# Ignore pylint complaint that this filename has a dash instead of an
# underscore.
# pylint:disable=invalid-name

import argparse
import logging
import os
import subprocess
import sys

# We’re importing the log package first because it needs to overwrite the
# app-wide logger class before any other module loads it.
import log
import update.launcher
import update.result
import update.result_store
import utc

logger = logging.getLogger(__name__)

_UPDATE_TIMEOUT_SECONDS = 60 * 10


def perform_update():
    result = run_update_script()
    update.result_store.write(result)


def run_update_script():
    logger.info('Launching update script: %s',
                update.launcher.UPDATE_SCRIPT_PATH)
    try:
        # The command arguments are trusted because they aren't based on user
        # input.
        subprocess.run(  # noqa: S603
            ['/usr/bin/sudo', update.launcher.UPDATE_SCRIPT_PATH],
            check=True,
            timeout=_UPDATE_TIMEOUT_SECONDS)
    except subprocess.TimeoutExpired:
        logger.error('Update process timed out')
        return make_update_result(update_error='The update timed out')
    except subprocess.CalledProcessError as e:
        logger.error('Update process terminated with failing exit code: %s',
                     str(e))
        return make_update_result(update_error=f'The update failed: {e}')

    logger.info('Update completed successfully')
    return make_update_result(update_error=None)


def make_update_result(update_error):
    return update.result.Result(error=update_error, timestamp=utc.now())


def main(_):
    root_logger = log.create_root_logger(logging.StreamHandler())
    root_logger.setLevel(logging.INFO)
    logger.info('Starting TinyPilot update')
    perform_update()


if __name__ == '__main__':
    # Ensure that the script doesn't have unnecessary privileges.
    if os.geteuid() == 0:
        print("This script doesn't require root privileges.", file=sys.stderr)
        print('Please re-run as tinypilot:', file=sys.stderr)
        print('  runuser tinypilot --command',
              f"'{' '.join(sys.argv)}'",
              file=sys.stderr)
        sys.exit(1)

    parser = argparse.ArgumentParser(
        prog='TinyPilot Update Service',
        formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    main(parser.parse_args())