Source code for digraphx.skeleton
"""
This is a skeleton file that can serve as a starting point for a Python
console script. To run this script uncomment the following lines in the
``[options.entry_points]`` section in ``setup.cfg``::
console_scripts =
fibonacci = digraphx.skeleton:run
Then run ``pip install .`` (or ``pip install -e .`` for editable mode)
which will install the command ``fibonacci`` inside your current environment.
Besides console scripts, the header (i.e. until ``_logger``...) of this file can
also be used as template for Python modules.
Note:
This file can be renamed depending on your needs or safely removed if not needed.
References:
- https://setuptools.pypa.io/en/latest/userguide/entry_point.html
- https://pip.pypa.io/en/stable/reference/pip_install
"""
import argparse
import logging
import sys
from digraphx import __version__
__author__ = "Wai-Shing Luk"
__copyright__ = "Wai-Shing Luk"
__license__ = "MIT"
_logger = logging.getLogger(__name__)
# ---- Python API ----
# The functions defined in this section can be imported by users in their
# Python scripts/interactive interpreter, e.g. via
# `from digraphx.skeleton import fib`,
# when using this Python module as a library.
[docs]
def fib(n):
"""Fibonacci example function
Args:
n (int): integer
Returns:
int: n-th Fibonacci number
"""
assert n > 0
a, b = 1, 1
for _i in range(n - 1):
a, b = b, a + b
return a
# ---- CLI ----
# The functions defined in this section are wrappers around the main Python
# API allowing them to be called directly from the terminal as a CLI
# executable/script.
[docs]
def parse_args(args):
"""Parse command line parameters
Args:
args (List[str]): command line parameters as list of strings
(for example ``["--help"]``).
Returns:
:obj:`argparse.Namespace`: command line parameters namespace
"""
parser = argparse.ArgumentParser(description="Just a Fibonacci demonstration")
parser.add_argument(
"--version",
action="version",
version=f"digraphx {__version__}",
)
parser.add_argument(dest="n", help="n-th Fibonacci number", type=int, metavar="INT")
parser.add_argument(
"-v",
"--verbose",
dest="loglevel",
help="set loglevel to INFO",
action="store_const",
const=logging.INFO,
)
parser.add_argument(
"-vv",
"--very-verbose",
dest="loglevel",
help="set loglevel to DEBUG",
action="store_const",
const=logging.DEBUG,
)
return parser.parse_args(args)
[docs]
def setup_logging(loglevel):
"""Setup basic logging
Args:
loglevel (int): minimum loglevel for emitting messages
"""
logformat = "[%(asctime)s] %(levelname)s:%(name)s:%(message)s"
logging.basicConfig(
level=loglevel, stream=sys.stdout, format=logformat, datefmt="%Y-%m-%d %H:%M:%S"
)
[docs]
def main(args):
"""Wrapper allowing :func:`fib` to be called with string arguments in a CLI fashion
Instead of returning the value from :func:`fib`, it prints the result to the
``stdout`` in a nicely formatted message.
Args:
args (List[str]): command line parameters as list of strings
(for example ``["--verbose", "42"]``).
"""
args = parse_args(args)
setup_logging(args.loglevel)
_logger.debug("Starting crazy calculations...")
print(f"The {args.n}-th Fibonacci number is {fib(args.n)}")
_logger.info("Script ends here")
[docs]
def run():
"""Calls :func:`main` passing the CLI arguments extracted from :obj:`sys.argv`
This function can be used as entry point to create console scripts with setuptools.
"""
main(sys.argv[1:])
if __name__ == "__main__":
# ^ This is a guard statement that will prevent the following code from
# being executed in the case someone imports this file instead of
# executing it as a script.
# https://docs.python.org/3/library/__main__.html
# After installing your project with pip, users can also run your Python
# modules as scripts via the ``-m`` flag, as defined in PEP 338::
#
# python -m digraphx.skeleton 42
#
run()