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From: J on 12 Aug 2010 12:19
How do you use OptParse with constants?

Example:
usage = 'Usage: %prog [OPTIONS]'
parser = OptionParser(usage)
parser.add_option('-l','--level',
action='store_const',
default=LOG_INFO,
help='Set the log level to inject into syslog (either an\
integer [0 - 7] or one of LOG_EMERG, LOG_ALERT,LOG_CRIT,\
LOG_ERR, LOG_WARNING, LOG_NOTICE, LOG_INFO, LOG_DEBUG')
(options,args) = parser.parse_args()

print options

always returns {'level':None} regarless of whether I call it with an
int (0 - 7) or the const name (LOG_*)

I'm importing syslog like so:

from syslog import *

so all the syslog constants should be available to me at run time (at
least that's my understanding) so I'm doing something wrong here or
just not understanding how to do a constant as an option.

The basic gist of the above is that I'm writing a tool to do basic
syslog testing by injecting messages and making sure they end up in
the correct log file... I can do all of this manually or in a loop by
looping through the various log levels, however, I want to be able to
specify them at run-time using an optional argument. Any ideas on how
to make this work, or at least why it's not doing what I thought it
would do?

Cheers
Jeff
From: Robert Kern on 12 Aug 2010 12:41
On 8/12/10 11:19 AM, J wrote:
> How do you use OptParse with constants?
>
> Example:
> usage = 'Usage: %prog [OPTIONS]'
> parser = OptionParser(usage)
> parser.add_option('-l','--level',
> action='store_const',
> default=LOG_INFO,
> help='Set the log level to inject into syslog (either an\
> integer [0 - 7] or one of LOG_EMERG, LOG_ALERT,LOG_CRIT,\
> LOG_ERR, LOG_WARNING, LOG_NOTICE, LOG_INFO, LOG_DEBUG')
> (options,args) = parser.parse_args()
>
> print options
>
> always returns {'level':None} regarless of whether I call it with an
> int (0 - 7) or the const name (LOG_*)

http://docs.python.org/library/optparse#standard-option-actions

'store_const' means that the option is a flag without arguments and stores the
value provided by the 'const' keyword to add_option() (it defaults to None so
that's what you get when you use that flag). This is not what you want. You just
want the default 'store' action.

--
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
that is made terrible by our own mad attempt to interpret it as though it had
an underlying truth."
-- Umberto Eco

From: J on 12 Aug 2010 13:47
On Thu, Aug 12, 2010 at 12:41, Robert Kern <robert.kern(a)gmail.com> wrote:
> On 8/12/10 11:19 AM, J wrote:
>>
>> How do you use OptParse with constants?

> http://docs.python.org/library/optparse#standard-option-actions
>
> 'store_const' means that the option is a flag without arguments and stores
> the value provided by the 'const' keyword to add_option() (it defaults to
> None so that's what you get when you use that flag). This is not what you
> want. You just want the default 'store' action.

Thanks Robert...

Sigh... head -> desk -> repeat :)
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