[RFC] Custom Providers about dotslash

[alilleybrinker]

Thanks for drafting this initial pass! One thought that occurs to me is that, if the single parameter is JSON, it should be standard JSON, and not the loose JSON accepted by the dotslash tool. This is just because it's not super standardized and cross-language may cause parsing complexities / problems for people writing providers (which may or may not be written in Rust).

Another thought is that the "streaming output to stdout so the provider doesn't need / get to know layout" is a nice idea! I'm imagining the case of the draft GitLab provider, I think this would mean needing to redirect the output of the subcommand to stdout, which isn't too terrible. The one constraint is we'd probably want some protocol for how to handle things going wrong. If we assume providers may basically delegate to a subcommand (like the GitHub and GitLab providers), those subcommands might write error messages to stdout if they're poorly-written. It may be good to specify that providers should write errors to stderr so they can be printed to the dotslash user, and also to use error return codes properly in the provider binary.

[bolinfest]

if the single parameter is JSON, it should be standard JSON

Yes, we would absolutely do that. Though FYI, I just updated the docs last night to list "experimental commands":

https://dotslash-cli.com/docs/flags/

FYI, today you can do:

dotslash -- parse DOTSLASH_FILE

to get the "pure JSON" of a DotSlash file, if that's helpful for any sort of tooling you build around DotSlash.