nix flake: use lib.mkAfter put the host list at the end

[toastal]

At present, if a user uses networking.stevenBlockHosts.enable = true in tandem with networking.extraHosts, the extraHosts will put be put after which makes it very difficult to see the custom adds with even the $PAGER operating a bit slow due to file size. I would propose putting this project’s hosts at the end of the hosts file. Meaning:

{
  networking = {
    stevenBlockHosts.enable = true;
    extraHosts = ''
      127.0.0.1 myproject.localhost
    '';
  };
}

will now output

127.0.0.1 localhost
::1 localhost

127.0.0.1 myproject.localhost

# Title: StevenBlack/hosts with the fakenews extension
#
# …

NOTE: using lib.* like #2813 to avoid a potential merge conflict

---

Also has been open @ https://gitlab.com/StevenBlack/hosts/-/merge_requests/3

[Pandapip1]

Not too familiar with the mkOrder-like nix functions, but this looks sane to me. Have not tested this, however, and this does seem like it has the potential of breaking things.

[toastal]

@Pandapip1 mkOrder will let you ‘unprioritize’ an appended string/list. In this case, since this hosts lists is 10s of 1000s of lines long, it is a pain to find your custom settings as even the $PAGER will chug on opening a file this long. But also Unix’s head is faster than tail due to how files work so this could really help those reading their settings.

[benjamb]

Not too familiar with the mkOrder-like nix functions, but this looks sane to me. Have not tested this, however, and this does seem like it has the potential of breaking things.

Agreed, changing the order has the potential to change the behaviour for users. Perhaps this could be controlled via another config option?

[toastal]

Agreed, changing the order has the potential to change the behaviour for users. Perhaps this could be controlled via another config option?

This is true, but has 2 issue. The 1st being as mentioned, the user has a hard time getting to the hosts values they have set, but 2nd the first match in the hosts files is what the system will use… meaning that if the user wants to override xxx.com, they will not be able to since by default, Nix will append custom values to end. Having used the Python scripts in the past, the behavior was to append to the StevenBlack hosts to the file, not prepend. I think this is a pretty important thing to consider & having thought about it, the current behavior could actually be considered a ‘bug’.

[Pandapip1]

I'm gonna assume that the author of this PR has tested this. Assuming it works correctly, this is good to merge and seems like a reasonable change.

[toastal]

@Pandapip1 I have tested for several months since I first opened the merge request on GitLab after the maker said GitLab was a supported mirror. …Hence many rebases.

[Pandapip1]

Sounds like this should be merged then

[benjamb]

I suppose given it's the first match that will be used, thus any overrides would need to be at the top, this does make sense. I think any chance of this changing the behaviour for any users is pretty slim.