im writing a NixOS module for the bore TCP tunnel service. So far I have a working version in my own flake that im using in a few of my servers right now: https://github.com/zSuperx/nix-bore. But I was thinking that this could be nice to have within nixpkgs itself as a builtin module, so I'm going through the contributing guide for modules and editing some of the types and whatnot. These are the questions I have right now:

Since the module im writing has options for setting ports, im assuming i should be using type = lib.types.port whenever possible?

Likewise, I'm adding a secretFile option so the systemd service reads the secret from a file rather than plaintext. Should I be using type = lib.types.path for this option? or just lib.types.str? I see a few path options in the type definitions file for nixpkgs, so just wanted to double check.

When actually evaluating and creating the systemd service file, since the set options values are being processed and interpolated into the serviceConfig.ExecStart bash script, when should I be using lib.escapeShellArg(s), if at all?

and last thing (for now) that im unsure about is the use of lib.literalExpression. I see it show up in a few modules I've been reading here and there, but I don't know what the actual use-case is or when it's preferred over a string for an option's description.

sorry if this is a lot of text to send at once. I had originally asked someone via the NixOS discord, and they directed me here. Let me know if I should post this in a different channel or something.

im writing a NixOS module for the bore TCP tunnel service. So far I have a working version in my own flake that im using in a few of my servers right now: https://github.com/zSuperx/nix-bore. But I was thinking that this could be nice to have within nixpkgs itself as a builtin module, so I'm going through the contributing guide for modules and editing some of the types and whatnot. These are the questions I have right now:

Since the module im writing has options for setting ports, im assuming i should be using type = lib.types.port whenever possible?

Likewise, I'm adding a secretFile option so the systemd service reads the secret from a file rather than plaintext. Should I be using type = lib.types.path for this option? or just lib.types.str? I see a few path options in the type definitions file for nixpkgs, so just wanted to double check.

When actually evaluating and creating the systemd service file, since the set options values are being processed and interpolated into the serviceConfig.ExecStart bash script, when should I be using lib.escapeShellArg(s), if at all?

and last thing (for now) that im unsure about is the use of lib.literalExpression. I see it show up in a few modules I've been reading here and there, but I don't know what the actual use-case is or when it's preferred over a string for an option's description.

sorry if this is a lot of text to send at once. I had originally asked someone via the NixOS discord, and they directed me here. Let me know if I should post this in a different channel or something. And thanks in advance!