Is it ‘allowed’ to get parameters like this

[Cecil Westerhof]

It has been a while since I worked with Python. I wanted to get some
stats about the idle time of my computer, so that was a good moment to
pick up Python again. ;-)


As I understood it getopt is the way to get the parameters for your
script. But at the moment it looks a bit like overkill, my script does
not have much parameters as parameter_error shows:
def parameter_error():
    print('Error: {0} [ --5 | --10 | --20 | --25 ] --all | --this-month | --this-year | --today'
          .format(basename(sys.argv[0])))
    sys.exit(1)

So at the moment this is my init function:
def init():
    global conn
    global cursor
    global vmstat_params

    arg_length = len(sys.argv)
    if   (arg_length == 1):
        period       = '--today'
        slice_length = 20
    elif (arg_length == 2):
        period       = sys.argv[1]
        slice_length = 20
    elif (arg_length == 3):
        period = sys.argv[2]
        if (sys.argv[1] in ['--5', '--10', '--20', '--25']):
            slice_length = int(sys.argv[1][2:])
        else:
            parameter_error()
    else:
        parameter_error()
    conn            = connect(expanduser('~/Databases/general.sqlite'))
    cursor          = conn.cursor()
    all_data        = '%'
    today           = cursor.execute('SELECT CURRENT_DATE').fetchone()[0]
    this_month      = today[0:8] + '%'
    this_year       = today[0:5] + '%'
    if   (period == '--today'):
        vmstat_params = [today,      slice_length]
    elif (period == '--this-month'):
        vmstat_params = [this_month, slice_length]
    elif (period == '--this-year'):
        vmstat_params = [this_year,  slice_length]
    elif (period == '--all'):
        vmstat_params = [all_data,   slice_length]
    else:
        parameter_error()

Is this acceptable, or is it a big no-no?

By the way: the reason I fetch today from the database is that I work
with UTC dates.

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof