Busk at 15:33, 8 April 2023

2023-04-08T15:33:16Z

Busk at 12:25, 8 April 2023

2023-04-08T12:25:07Z

Busk: Created page with "https://stackoverflow.com/questions/10551117/setting-options-from-environment-variables-when-using-argparse"

2023-04-08T12:23:19Z

Created page with "https://stackoverflow.com/questions/10551117/setting-options-from-environment-variables-when-using-argparse"

New page

https://stackoverflow.com/questions/10551117/setting-options-from-environment-variables-when-using-argparse

← Older revision		Revision as of 15:33, 8 April 2023
Line 3:		Line 3:

	https://gist.github.com/orls/51525c86ee77a56ad396		https://gist.github.com/orls/51525c86ee77a56ad396
		+
		+
		+	# Example 1
		+	```
		+	import argparse
		+	import os
		+
		+	class EnvDefault(argparse.Action):
		+	def __init__(self, envvar, required=True, default=None, **kwargs):
		+	if not default and envvar:
		+	if envvar in os.environ:
		+	default = os.environ[envvar]
		+	if required and default:
		+	required = False
		+	super(EnvDefault, self).__init__(default=default, required=required,
		+	**kwargs)
		+
		+	def __call__(self, parser, namespace, values, option_string=None):
		+	setattr(namespace, self.dest, values)
		+	```
		+
		+	```
		+	import argparse
		+	from envdefault import EnvDefault
		+
		+	parser=argparse.ArgumentParser()
		+	parser.add_argument(
		+	"-u", "--url", action=EnvDefault, envvar='URL',
		+	help="Specify the URL to process (can also be specified using URL environment variable)")
		+	args=parser.parse_args()
		+	```
		+
		+
		+	# Another Example
		+	```
		+	import argparse
		+	import os
		+
		+	# Courtesy of http://stackoverflow.com/a/10551190 with env-var retrieval fixed
		+	class EnvDefault(argparse.Action):
		+	"""An argparse action class that auto-sets missing default values from env
		+	vars. Defaults to requiring the argument."""
		+
		+	def __init__(self, envvar, required=True, default=None, **kwargs):
		+	if not default and envvar:
		+	if envvar in os.environ:
		+	default = os.environ[envvar]
		+	if required and default:
		+	required = False
		+	super(EnvDefault, self).__init__(default=default, required=required,
		+	**kwargs)
		+
		+	def __call__(self, parser, namespace, values, option_string=None):
		+	setattr(namespace, self.dest, values)
		+
		+	# functional sugar for the above
		+	def env_default(envvar):
		+	def wrapper(**kwargs):
		+	return EnvDefault(envvar, **kwargs)
		+	return wrapper
		+	```
		+
		+	```
		+	import argparse
		+
		+	from EnvDefault import env_default
		+
		+
		+	if __name__ == "__main__":
		+
		+	parser = argparse.ArgumentParser(
		+	description="use env vars as defaults for argparse"
		+	)
		+
		+	parser.add_argument(
		+	"--alpha", "-a",
		+	action=env_default('ALPHA'),
		+	required=False,
		+	help="""Optional. Value from CLI will be used if present, or from env var ALPHA.
		+	If neither of these is present, value is None becasue no fallback default
		+	was given"""
		+	)
		+
		+	parser.add_argument(
		+	"--beta", "-b",
		+	action=env_default('BETA'),
		+	required=True,
		+	help="""Required. Value from CLI will be used if present, or from env var BETA.
		+	If neither of these is present, it's an error"""
		+	)
		+
		+	parser.add_argument(
		+	"--gamma", "-g",
		+	action=env_default('GAMMA'),
		+	required=True,
		+	default=9001,
		+	help="""Value from CLI will be used if present, or from env var GAMMA.
		+	If neither of these is present, default of 9001 is used"""
		+	)
		+
		+	print parser.parse_args()
		+	```

← Older revision		Revision as of 12:25, 8 April 2023
Line 1:		Line 1:
	https://stackoverflow.com/questions/10551117/setting-options-from-environment-variables-when-using-argparse		https://stackoverflow.com/questions/10551117/setting-options-from-environment-variables-when-using-argparse
		+
		+
		+	https://gist.github.com/orls/51525c86ee77a56ad396

Argparse set from env var - Revision history

Busk at 15:33, 8 April 2023

Busk at 12:25, 8 April 2023

Busk: Created page with "https://stackoverflow.com/questions/10551117/setting-options-from-environment-variables-when-using-argparse"