def get_global(name):
    return os.getenv(_get_env_name(name))

def set_global(name, value):
    os.putenv(_get_env_name(name), value)

def unset_global(name):
    os.unsetenv(_get_env_name(name))

def _get_env_name(name):
    return 'TILT_GLOBAL_VAR_%s' % name.upper()