Problem#
There is click module that allows you to create comman dline interfaces for your python scripts.
The advantages of click are
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| import click
@click.command()
@click.option('--count', default=1, help='Number of greetings.')
@click.option('--name', prompt='Your name',
help='The person to greet.')
def hello(count, name):
"""Simple program that greets NAME for a total of COUNT times."""
for x in range(count):
click.echo('Hello %s!' % name)
if __name__ == '__main__':
hello()
|
- straightforward argument parsing strategy (in comparison to the standard argparse )
Click doesn’t support config files by default. There is a number of additional modules that implement this feature.
Comparison#
| feature | click-config | click-configfile | click_config_file | SO snippet |
|---|
| Last commit in the repository | May 5, 2015 | Sep 24, 2017 | Jan 23, 2018 | - |
| Supports ini | yes | yes | yes | easy to implement |
| Supports json | no | no | yes with strange extension technique | easy to implement |
| Supports yaml | yes | no | yes with strange extension technique | yes |
| implementation notes | click-config provides a decorator that takes a python object and overwrites its attributes with values passed into the program via command line arguments. | through context_settings | usable by simply adding the appropriate decorator | Default values from click.option don’t work as expected. They override values from the file. One have to check for defaults manually. Not sure if environment variables work nicely. |
Syntax examples#
click-config#
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| from __future__ import print_function
import click
import click_config
class config(object):
class logger(object):
level = 'INFO'
class mysql(object):
host = 'localhost'
@click.command()
@click_config.wrap(module=config, sections=('logger', 'mysql'))
def main():
print('log level: {}, mysql host: {}'.format(
config.logger.level,
config.mysql.host
))
if __name__ == '__main__':
main()
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| # BASIC SOLUTION FOR: Command that uses one or more configuration files.
import click
CONTEXT_SETTINGS = dict(default_map=ConfigFileProcessor.read_config())
@click.command(context_settings=CONTEXT_SETTINGS)
@click.option("-n", "--number", "numbers", type=int, multiple=True)
@click.pass_context
def command_with_config(ctx, numbers):
"""Example for a command that uses an configuration file"""
pass
...
if __name__ == "__main__":
command_with_config()
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click_config_file#
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| @click.command()
@click.option('--name', default='World', help='Who to greet.')
@click_config_file.configuration_option()
def hello(name):
click.echo('Hello {}!'.format(name))
|
Stack overflow snippet#
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| # Custom Class:
def CommandWithConfigFile(config_file_param_name):
class CustomCommandClass(click.Command):
def invoke(self, ctx):
config_file = ctx.params[config_file_param_name]
if config_file is not None:
with open(config_file) as f:
config_data = yaml.load(f)
for param, value in ctx.params.items():
if value is None and param in config_data:
ctx.params[param] = config_data[param]
return super(CustomCommandClass, self).invoke(ctx)
return CustomCommandClass
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Using Custom Class:#
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| @click.command(cls=CommandWithConfigFile('config_file'))
@click.argument("arg")
@click.option("--opt")
@click.option("--config_file", type=click.Path())
def main(arg, opt, config_file):
|
Test Code:#
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| # !/usr/bin/env python
import click
import yaml
@click.command(cls=CommandWithConfigFile('config_file'))
@click.argument("arg")
@click.option("--opt")
@click.option("--config_file", type=click.Path())
def main(arg, opt, config_file):
print("arg: {}".format(arg))
print("opt: {}".format(opt))
print("config_file: {}".format(config_file))
main('my_arg --config_file config_file'.split())
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Test Results:
arg: my_arg
opt: my_opt
config_file: config_file