Python 2.7 - Argparse Usage
Hello,
I'm using Python 2.7 and the Argparse module to parse command line parameters. I have the following stripped down code, but I'd like to use subparsers and parents to make the help more obvious. I have the following usage cases that I am trying to accommodate, but I can't figure out how to do this properly with subparsers. If someone could nudge me in the right direction with a couple of generic examples, I would appreciate it.
script.py # script should execute and assume the -i switch
script.py -i # script should execute in interactive mode
script.py -f [fname] # The script should execute in file mode. The script takes fname as a parameter and executes. In my code below, I have the fname validated via another function, but I can't figure that out with subparsers
script.py -E [endpoint] -s [start_time] -e [end_time] # The script executes in endpoint mode. The -s is mandatory with -E and -e is optional. However, if parameters are passed they must be validated with the valid_date function. I have this working in the code below, but I can't figure it out with subparsers. I may at some point also try to validate the endpoint parameter.
"-a" and "-x" are optional parameters and may be used with any of the three modes listed above. I know this is accomplished via parents. However, I can't get this working the closest I've come is code that doesn't error out. However, --help does not display existence of the switches either.
I'm using Python 2.7 and the Argparse module to parse command line parameters. I have the following stripped down code, but I'd like to use subparsers and parents to make the help more obvious. I have the following usage cases that I am trying to accommodate, but I can't figure out how to do this properly with subparsers. If someone could nudge me in the right direction with a couple of generic examples, I would appreciate it.
script.py # script should execute and assume the -i switch
script.py -i # script should execute in interactive mode
script.py -f [fname] # The script should execute in file mode. The script takes fname as a parameter and executes. In my code below, I have the fname validated via another function, but I can't figure that out with subparsers
script.py -E [endpoint] -s [start_time] -e [end_time] # The script executes in endpoint mode. The -s is mandatory with -E and -e is optional. However, if parameters are passed they must be validated with the valid_date function. I have this working in the code below, but I can't figure it out with subparsers. I may at some point also try to validate the endpoint parameter.
"-a" and "-x" are optional parameters and may be used with any of the three modes listed above. I know this is accomplished via parents. However, I can't get this working the closest I've come is code that doesn't error out. However, --help does not display existence of the switches either.
import argparse
from time import time as timer
import sys
def valid_date(iso8601):
pass
def valid_file(parser, fname):
pass
return fname
def file_mode(fname, audit, staging):
print("Start in file mode. Audit is {} and staging is {}.".format(audit, staging))
sys.exit(0)
def endpoint_mode(endpoint, start_time, end_time, audit, staging):
print("Start in endpoint mode. Audit is {} and staging is {}.".format(audit, staging))
sys.exit(0)
def interactive_mode(audit, staging):
print("Start in interactive mode. Audit is {} and staging is {}.".format(audit, staging))
def main():
parser = argparse.ArgumentParser(description="This is my test ArgParse script.")
group = parser.add_mutually_exclusive_group()
group.add_argument("-i", \
dest="interactive", \
action="store_true", \
help="Run the script interactively. This is the default " + \
"mode if no options are specfied.")
group.add_argument("-f", \
dest="fname", \
help="Run the script against an input file.", \
metavar="FILE", \
type=lambda x: valid_file(parser, x))
group.add_argument("-E", \
dest="endpoint",
help="Run the script against a specific endpoint.",
metavar="ENDPOINT")
parser.add_argument("-a", \
dest="audit", \
action="store_true", \
help="Audit only.")
parser.add_argument("-x", \
dest="staging", \
action="store_true", \
help="Switches queries to use staging.")
parser.add_argument("-s", \
dest="start_time", \
help="Specify a start date. This is mandatory with the -E switch.", \
metavar="DATE",
type=valid_date)
parser.add_argument("-e", \
dest="end_time", \
help="Specify an end date. This optional with the -E switch.", \
metavar="DATE")
args = parser.parse_args()
audit = args.audit
staging = args.staging
interactive = args.interactive
fname = args.fname
endpoint = args.endpoint
start_time = args.start_time
end_time = args.end_time
if not len(sys.argv) > 1:
interactive_mode(audit, staging)
if args.interactive is True:
interactive_mode(audit, staging)
if '-f' in sys.argv:
file_mode(fname, audit, staging)
if '-E' in sys.argv:
endpoint_mode(endpoint, start_time, end_time, audit, staging)
Do more with
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
Have you seen docopt? Until now, I haven't seen this myself but I am glad I did now.
You'll have to explicitly do the argument-validation yourself but it gets most of what I understand of your requirements.
testing:
You'll have to explicitly do the argument-validation yourself but it gets most of what I understand of your requirements.
"""Usage: prog [-a] [-x]
prog ( -i | -f FNAME | -E ENDPOINT -s START_TIME [-e END_TIME] ) [-a] [-x]
Process FILE and optionally apply correction to either left-hand side or
right-hand side.
Arguments:
FNAME must be validated by another function
ENDPOINT The -s is mandatory with -E and -e is optional.
START_TIME If passed, must be validated with the valid_date function
END_TIME ditto
Options:
-h --help
-i script should execute in interactive mode
-f script should execute in file mode
-E script executes in endpoint mode
-a Audit only
-x use staging
"""
from docopt import docopt
if __name__ == '__main__':
d = docopt(__doc__) # parse arguments based on docstring above
print d
testing:
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
C:\>python docopttest.py
{'-E': False,
'-a': False,
'-e': False,
'-f': False,
'-i': False,
'-s': False,
'-x': False,
'ENDPOINT': None,
'END_TIME': None,
'FNAME': None,
'START_TIME': None}
C:\>python docopttest.py -i
{'-E': False,
'-a': False,
'-e': False,
'-f': False,
'-i': True,
'-s': False,
'-x': False,
'ENDPOINT': None,
'END_TIME': None,
'FNAME': None,
'START_TIME': None}
C:\>python docopttest.py -i -a -z
Usage: prog [-a] [-x]
prog ( -i | -f FNAME | -E ENDPOINT -s START_TIME [-e END_TIME] ) [-a] [-x]
C:\>python docopttest.py -i -a -x
{'-E': False,
'-a': True,
'-e': False,
'-f': False,
'-i': True,
'-s': False,
'-x': True,
'ENDPOINT': None,
'END_TIME': None,
'FNAME': None,
'START_TIME': None}
C:\>python docopttest.py -f
Usage: prog [-a] [-x]
prog ( -i | -f FNAME | -E ENDPOINT -s START_TIME [-e END_TIME] ) [-a] [-x]
C:\>python docopttest.py -f foo.bar
{'-E': False,
'-a': False,
'-e': False,
'-f': True,
'-i': False,
'-s': False,
'-x': False,
'ENDPOINT': None,
'END_TIME': None,
'FNAME': 'foo.bar',
'START_TIME': None}
C:\>python docopttest.py -E EP_here
Usage: prog [-a] [-x]
prog ( -i | -f FNAME | -E ENDPOINT -s START_TIME [-e END_TIME] ) [-a] [-x]
C:\>python docopttest.py -E EP_here -s 2017-01-01
{'-E': True,
'-a': False,
'-e': False,
'-f': False,
'-i': False,
'-s': True,
'-x': False,
'ENDPOINT': 'EP_here',
'END_TIME': None,
'FNAME': None,
'START_TIME': '2017-01-01'}
C:\>python docopttest.py -E EP_here -s 2017-01-01 -x
{'-E': True,
'-a': False,
'-e': False,
'-f': False,
'-i': False,
'-s': True,
'-x': True,
'ENDPOINT': 'EP_here',
'END_TIME': None,
'FNAME': None,
'START_TIME': '2017-01-01'}
C:\>python docopttest.py -E EP_here -s 2017-01-01 -e 2017-10-01
{'-E': True,
'-a': False,
'-e': True,
'-f': False,
'-i': False,
'-s': True,
'-x': False,
'ENDPOINT': 'EP_here',
'END_TIME': '2017-10-01',
'FNAME': None,
'START_TIME': '2017-01-01'}
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