Script Template for Python

Python is currently the scripting language that I use most often. Since Python 2 is clearly out of support now, I only use Python 3. The script might or might not work with Python 2.

The script supports short and long parameters. As usual, the documentation can be printed with --help:

usage: template.py [-h] [-l {DEBUG,INFO,WARNING,ERROR,CRITICAL}] -n NUMBER
                   [-f FILE]
                   text [text ...]

Template for Python Scripts. Can be used as a basis for simple scripts.

positional arguments:
  text                  Text arguments. One or more can be appended to the
                        call.

optional arguments:
  -h, --help            show this help message and exit
  -l {DEBUG,INFO,WARNING,ERROR,CRITICAL}, --loglevel {DEBUG,INFO,WARNING,ERROR,CRITICAL}
                        Define log level.
  -n NUMBER, --number NUMBER
                        A number
  -f FILE, --file FILE  A file

Template

Download Script

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

# Copyright (c) 2014 Christian Mauderer <oss@c-mauderer.de>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import logging
import argparse
import sys

parser = argparse.ArgumentParser(
    description=(
        "Template for Python Scripts.\n"
        "Can be used as a basis for simple scripts.\n"
    ))

parser.add_argument(
    "text",
    help="Text arguments. One or more can be appended to the call.",
    nargs='+'
)
parser.add_argument(
    "-l", "--loglevel",
    help = "Define log level.",
    type = str.upper,
    choices = ['DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL'],
    default = 'WARNING'
)
parser.add_argument(
    "-n", "--number",
    help="A number",
    type=float,
    required=True
)
parser.add_argument(
    "-f", "--file",
    help="A file",
    type=argparse.FileType('r')
)

args = parser.parse_args()

# set up logging
numeric_loglevel = getattr(logging, args.loglevel)
logging.basicConfig(level = numeric_loglevel)
logger = logging.getLogger(__name__)
logger.info("Started with the following options: {}".format(str(args)))

print('Text arguments:', args.text)

# vim: set ts=4 sw=4 et:

The script tries to follow the Python Style Guide (PEP 8).

Profiling

For scripts that need a lot of CPU, it's sometimes useful to find out what lines are using a lot of time. Profiling shows exactly that: How much CPU is consumed by which function.

Python uses cProfile for that. To analyze a script, it can be started with some extra parameters:

sh> python -m cProfile template.py -l info -n 10 eins zwei

The output is a pure text form. To get a graphical view, pyprof2calltree can be used. For example:

sh> python -m cProfile -o template.cprof template.py -l info -n 10 eins zwei
...
sh> pyprof2calltree -k -i template.cprof

This will call KCacheGrind: