Anyone with experience using NixOS to create a Lemmy instance, please share any caveats and troubleshooting tips you have.

  • neoney@lemmy.neoney.dev
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    1 year ago

    Nixpkgs is by nature fully reproducible and declarative - that means you can’t write a nix package to just build from master branch. You also have to specify the sha256 hash to absolutely make sure the source is the same for everyone.
    With flakes, it’s a bit easier, because if the package you’re trying to build has a flake, you can just update it in your own lockfile and it will be rebuilt from the latest version.
    If using something from nixpkgs, you have to wait (or PR yourself) for someone to PR the update, or you can also use overrideAttrs to do a “private” fix.
    For example, I’m using the wlsunset program, but wanted to build from a different branch, so I did this:

          (wlsunset.overrideAttrs (old: {
            src = fetchFromSourcehut {
              owner = "~kennylevinsen";
              repo = old.pname;
              rev = "81cfb0b4f8e44db9e5ecb36222a24d53a953e6aa";
              sha256 = "sha256-Lxuhsk4/5EHuKPkBbaRtCCQ/LFvIxyc+VQYEoaVT484=";
            };
          }))
    

    This just changes the source attribute to another commit and another sha hash, and it works fine.

    • neoney@lemmy.neoney.dev
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      1 year ago

      In the end, the lag is just caused by the fact that it has to work. You never want to get some broken version that you want to avoid, so nix packages are always tested with the new versions, because it may turn out they may need some patching for that version, or they have some new dependencies.