Ignore unknown sys.argv

[isc-psulin]

I really like the ability to override args from my config from the cli, but it breaks a lot of other things that also rely on sys.argv like pytest and uvicorn. I have tried setting cli_exit_on_error=False, but it doesn't seem to stop it from blowing up with args that are not declared in the model if I have cli_parse_args=True.

How can I have it just ignore args it does not know so I can use it with pytest, uvicorn, etc...?

[hramezani]

@kschwab could you please take a look?

[kschwab]

@hramezani this is similar request as #391. I've added a config option that will ignore unknown args.

The docs still need to be updated to cover the different use cases of mixing a CliSettingsSource with other parsers (e.g., pytest, uvicorn, etc.). I'll try to get back to it here in the next few days.

[isc-psulin]

The solutions in #391 can work but require hard coding things to work with specific apps or just turn off CLI parsing if using certain apps. It is very common with Python apps to have another app load it - pytest, uvicorn, fastapi, memray - to just name a few I use off the top of my head, so these solutions are not ideal as they don't really acknowledge this common type of usage. I don't want application code that is specific to running tests so I am just turning off CLI parsing for these cases and will have to change the code if I need to use different launching apps.

[kschwab]

@isc-patrick the similarity with #391 relates to mixing multiple parsers in a single app. This is a general problem. e.g., #405 will add an option to ignore unknown CLI arguments. This is a great request and a good feature to have 👍

However, while this resolves not blowing up for unknown arguments, it now also parses any common arguments. If pytest, uvicorn, etc. have a flag --enable int and CliSettingsSource also has a flag --enable dict, it will blow up. So, what constitutes "blowing up" is specific to the app and requires app specific logic to correctly resolve. This may mean turning off the CLI, integrating the CLI, ignoring unknown arguments, etc., but these are all app specific details.

@hramezani, unfortunately, I am tight on time this week. I've updated the docs with respect to the new flag. I'll try to get back to a broader summary of this issue and #391 in the docs at a later time.

[isc-psulin]

@kschwab Thanks for the clarification. I mistook the disabling of the cli parsing via searching the argv[0] as that implementation. I completely agree that there is no way to avoid some of these issues because of the potentialof common arguments in different apps.