Add default directory to payjoin-cli

[zealsham]

SUMMARY

This PR enables payjoin-cli to automatically discover config files in standard locations following XDG Base Directory specification or use the current working directory . config values in the current working directory takes precedent over that of the xdg-compliant vlaue . If a required config value is missing in the current directory config , Payjoin-cli falls back to using values from the xdg-compliant directory config .
This pr closes #64

Changes

• Add config file search in XDG-compliant directories (~/.config/payjoin/)
• Current working directory takes precedent over xdg directory
• if a config value is missing in current working directory , fall back and use the config value in xdg-compliant directory

[coveralls]

Pull Request Test Coverage Report for Build 16737406990

Details

• 5 of 5 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.007%) to 85.853%

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Totals
Change from base Build 16728605627:	0.007%
Covered Lines:	7446
Relevant Lines:	8673

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💛 - Coveralls

[nothingmuch]

I think ensure_config_dirs can be split into a separate commit that can be saved for a follow-up PR addressing #896

Apart from my suggestion to hold off creating the directory entirely for this PR, I think this is ready, please squash the later commits to the first one, and update the message so it's up to date (please also update the short message to be a bit clearer, maybe "payjoin-cli: search for config.toml in standard locations" or something like that, not sure that fits in 50 char suggested limit)

[nothingmuch]

thanks for addressing all review comments

i missed a potential simplification that i think is worth doing, sorry for yet another round of feedback i should have thought of this earlier

[nothingmuch]

i missed this before but this is a bit confusing...

if find_config_path returns Some(./config.toml), then this is redundant, and if it returns Some(~/.config/payjoin-cli/config.toml) this is ignored, so this could be simplified:

Suggested change

	let file_source = config_path
	.map(|path| File::from(path).format(FileFormat::Toml).required(true))
	.unwrap_or_else(|| File::new("config.toml", FileFormat::Toml).required(false));
	config = config.add_source(file_source);
	let Some(path) = config_path {
	config = config.add_source(File::from(path).format(FileFormat::Toml).required(true));
	}

but thinking about it more, since the config crate provides cascading support, maybe the right behavior would be to add both? ~/.config/payjoin-cli/config.toml can set global defaults, and ./config.toml can override. both can be .required(false)? i think that would simplify this PR even more, avoiding the need to check if files exist altogether since the config crate can handle that for us

@DanGould thoughts on using config this way? is there any good reason why if ./config.toml exists ~/.config/payjoin-cli/config.toml should be ignored entirely like i previously suggested? afaik the e2e test will be unaffected since it passes explicit args for everything, and that will take precedence, and for manual testing it seems more convenient to have global defaults and local overrides. we can also add --ignore-global-config, --ignore-local-config bools (and --ignore-config-files?) to the CLI options, that have the effect of skipping the config file addition

sorry for only realizing this now

[DanGould]

I like the idea of cascading defaults. and the simplicity it provides.

it seems more convenient to have global defaults and local override

I agree.

we can also add --ignore-global-config, --ignore-local-config bools (and --ignore-config-files?) to the CLI options, that have the effect of skipping the config file addition

yes we can, though I'd like to see that held off on for the future and not block this PR (just clarifying, i know you're not suggesting this)

[nothingmuch]

I like the idea of cascading defaults. and the simplicity it provides.

cool. so yeah @zealsham i think this means we can completely remove all the exists check, just unconditionally add both paths as sources and mark required(false)

yes we can, though I'd like to see that held off on for the future and not block this PR (just clarifying, i know you're not suggesting this)

yeah if we ever need that kind of thing for testing it's simple to add, but for now we have everything we need since CLI args are provided for all values anyway

[zealsham]

@nothingmuch , implemented , i'll take on config flag pr after this and defaul config goes in if we are moving in that direction .

[nothingmuch]

thanks for sticking with this PR!