def main()

in application-workloads/jupyter/jupyterhub-classroom/scripts/bootstrap.py [0:0]
62 lines of code
3 McCabe index (conditional complexity)

def main():
    validate_host()
    install_prefix = os.environ.get('TLJH_INSTALL_PREFIX', '/opt/tljh')
    hub_prefix = os.path.join(install_prefix, 'hub')

    # Set up logging to print to a file and to stderr
    os.makedirs(install_prefix, exist_ok=True)
    file_logger_path = os.path.join(install_prefix, 'installer.log')
    file_logger = logging.FileHandler(file_logger_path)
    # installer.log should be readable only by root
    os.chmod(file_logger_path, 0o500)

    file_logger.setFormatter(logging.Formatter('%(asctime)s %(message)s'))
    file_logger.setLevel(logging.DEBUG)
    logger.addHandler(file_logger)

    stderr_logger = logging.StreamHandler()
    stderr_logger.setFormatter(logging.Formatter('%(message)s'))
    stderr_logger.setLevel(logging.INFO)
    logger.addHandler(stderr_logger)
    logger.setLevel(logging.DEBUG)

    logger.info('Checking if TLJH is already installed...')
    if os.path.exists(os.path.join(hub_prefix, 'bin', 'python3')):
        logger.info('TLJH already installed, upgrading...')
        initial_setup = False
    else:
        logger.info('Setting up hub environment')
        initial_setup = True
        # Install software-properties-common, so we can get add-apt-repository
        # That helps us make sure the universe repository is enabled, since
        # that's where the python3-pip package lives. In some very minimal base
        # VM images, it looks like the universe repository is disabled by default,
        # causing bootstrapping to fail.
        run_subprocess(['apt-get', 'update', '--yes'])
        run_subprocess(['apt-get', 'install', '--yes', 'software-properties-common'])
        run_subprocess(['add-apt-repository', 'universe'])

        run_subprocess(['apt-get', 'update', '--yes'])
        run_subprocess(['apt-get', 'install', '--yes', 
            'python3',
            'python3-venv',
            'python3-pip',
            'git'
        ])
        logger.info('Installed python & virtual environment')
        os.makedirs(hub_prefix, exist_ok=True)
        run_subprocess(['python3', '-m', 'venv', hub_prefix])
        logger.info('Set up hub virtual environment')

    if initial_setup:
        logger.info('Setting up TLJH installer...')
    else:
        logger.info('Upgrading TLJH installer...')

    pip_flags = ['--upgrade']
    if os.environ.get('TLJH_BOOTSTRAP_DEV', 'no') == 'yes':
        pip_flags.append('--editable')
    tljh_repo_path = os.environ.get(
        'TLJH_BOOTSTRAP_PIP_SPEC',
        'git+https://github.com/jupyterhub/the-littlest-jupyterhub.git'
    )

    run_subprocess([
        os.path.join(hub_prefix, 'bin', 'pip'),
        'install'
    ] + pip_flags + [tljh_repo_path])
    logger.info('Setup tljh package')

    logger.info('Starting TLJH installer...')
    os.execv(
        os.path.join(hub_prefix, 'bin', 'python3'),
        [
            os.path.join(hub_prefix, 'bin', 'python3'),
            '-m',
            'tljh.installer',
        ] + sys.argv[1:]
    )