configargparse - reading option from config only

[Loris Bennett]

Richard Damon <Richard at Damon-Family.org> writes:

> On 8/27/21 3:37 AM, Loris Bennett wrote:
>> Richard Damon <Richard at Damon-Family.org> writes:
>>
>>> On 8/26/21 6:01 AM, Loris Bennett wrote:
>>>> Hi,
>>>>
>>>> When using configargparse, it seems that if a value is to be read from a
>>>> config file, it also has to be defined as a command-line argument in
>>>> order to turn up as an attribute in the parser namespace.  
>>>>
>>>> I can sort of see why this is the case, but there are also some options
>>>> I would like to read just from the config file and not have them
>>>> available as command-line options.  This would be, say, to prevent the
>>>> number of options on the command-line from becoming bloated by
>>>> little-used settings.
>>>>
>>>> Is there an elegant way to do this?
>>>>
>>>> Cheers,
>>>>
>>>> Loris
>>>>
>>> Look at the read() member function to supply the file name to read. Then
>>> in the config object there will be sections for each section in the
>>> config file. No need for any of these to be 'options'
>> Do you have a link for this?  As far as I can see, the config files are
>> given in the following manner:
>>
>>   p = configargparse.ArgParser(default_config_files=['/etc/app/conf.d/*.conf', '~/.my_settings'])
>>
>> I can obviously just read the config file with configparser, but the
>> idea of configargparse is that an option can be specified as an option,
>> in a config file, or as an environment variable,
>>
>> As far as I can tell, configargparse only loads entries from the config
>> file into the appropriate namespace if they have also been defined as
>> long options (i.e. with '--').  I was hoping to access *all* the config
>> file entries, regardless of whether they are also options, since the
>> config is obviously being read.
>>
>> Cheers,
>>
>> Loris
>>
> I misread your question, I thought you were talking about configparse.
>
> Question is, if configargparse doesn't do what you want, then it isn't
> the right tool.
>
> It looks like configargparse is SPECIFICALLY designed to allow the use
> to use a file as a shorthand to present command line arguements. The
> whole parsing structure is based on an enumerated set of options, if
> that isn't what you have, it is the wrong tool.

I am not sure what you mean by using 

  a file as a shorthand to present command line arguements

since the command-line arguments are defined by caling the 'add_argument'
method of the configargparse object.  However, I agree with your
analysis that configargparse is the wrong tool for what I want to do.

I like the idea that a variable can be defined as a command-line option,
an entry in a config file, or as an environment variable.  However, when
I think about it, it seems that command-line options are essentially
different from parameters in a configuration file, not least because the
former need some sort of description for the output of '--help', whereas
the latter do not.

Cheers,

Loris
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