Re: Best practice for config files?

On 5/22/2025 7:09 PM, Rob Cliffe via Python-list wrote:
> 
> 
> On 22/05/2025 23:45, Mats Wichmann wrote:
>> On 5/22/25 13:59, Michael F. Stemper via Python-list wrote:
>>> I recently wrote a program to do some record-keeping for me. I found
>>> myself hard-coding a bunch of different values into it. This didn't
>>> seem right, so I made my first use of configparser.ConfigParser().
>>> Created the configuration file and everything is working fine.
>>>
>>> However, I wrote it based on the assumption that the program is
>>> running in the directory where the config file is stored, and has
>>> a specific name. I started having some second thoughts here.
>>>
>>> I thought about putting the location of the configuration file in
>>> the configuration file, but that seemed like a non-starter.[1]
>>>
>>> Should I specify the location of the config file with a command-line
>>> option, or is requiring the program to be executed in the directory
>>> containing the configuration file considered acceptable practice?
>> Eh, there are so many context-dependent practices that it's largely 
>> impossible to identify something to call a "best practice" these days. 
>> I'm going to make a couple of comments, but there's more to consider 
>> than just these thoughts.
>>
>> There's a sort-of-standard package called platformdirs (a successor to 
>> appdirs) which tries to tell you where to put things in a platform- 
>> independent way.
>>
>> https://pypi.org/project/platformdirs/
>> https://pypi.org/project/appdirs/
>>
>> This works nicely if you're building something to distribute, and you 
>> want to have a system-neutral way to access a config file. For 
>> personal stuff, that may be overkill. If it's only for you, just do 
>> what works. Enhancement: have a default location for the config file 
>> hard-coded, but provide a cmdline option to give an alternative.
>>
> Mats is absolutely correct that there is no "one size fits all" solution.
> However one solution that might or might not suit you (at least on 
> WIndows; I hope it's applicable to Unix) is to look at sys.path and 
> search for your configuration file in every directory it lists until you 
> find it (or give an error message if it
> isn't).  Alternatively look at the PATH envronment variable, which 
> contains a list of directories separated by semicolons and which you can 
> access as os.environ['PATH'] .
> Best wishes,
> Rob Cliffe

There is really no reason for a config file to be on the system path. On 
Windows, if it's not in the program's home directory (or a subdir of 
it), then it's common to be in the user's home directory.  That's 
assuming the program is expected to have possibly different 
configurations for different users.

Otherwise there's a \Users\Public directory (or 
C:\Users\Public\Documents) that could be used, if all users are desired 
to use the same config file. Or, again for all users, in c:\ProgramData, 
as long is you don't mind having to write the config file with admin 
privileges.

The most flexible plan would be to have the program look in all those 
likely places for its config file. For more flexibility - but this is 
unnecessarily complicated for many applications - have the program look 
first on the command line for the config directory, then for an 
environmental variable, then in those likely places.
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