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by ghusbands 966 days ago
It feels like every time someone complains about Nix being hard to use and understand, there's a response that claims it's great and that you just have to use X or Y. Oddly, what X or Y are seem to differ greatly.
2 comments

That's literally why we make tools, so yes. Claims of Nix is too hard are like the BTRFS is unstable camp (which thankfully has mostly died out): they're holdovers from when these things were true.

You have an entire industry building on top of Nix. Nix itself is complex because it has to be. Its DSL didn't need to be so terrible but the ideas Nix packages are not easy.

So use the layer above the thing that is complex to make that thing easy. That's what tools are for.

> Claims of Nix is too hard are like the BTRFS is unstable camp (which thankfully has mostly died out): they're holdovers from when these things were true.

This is a grossly misleading comparison. Or at least, it's maybe not the comparison you want to make.

btrfs being unstable persists for a couple of reasons:

- Even casual users have pretty much zero tolerance for a filesystem that self-destructs. Especially when the filesystem integrates RAID and snapshot functionality, so self-destructing takes backup infrastructure with it.

- There are features that are legitimately unstable (RAID5/6), have unexpected side effects (defragmenting breaking reflinks), and seem unfinished (dedup requires external tools)

Nix being too hard to use comes from, well, the stuff I mentioned, which is all from the last few years. Or, the laptop I installed NixOS on just this year, where the install finished, and then the user is left without any guidance how to set up their system. For me, that's OK; I can fire up a terminal and run nano then rebuild the system.

But for any first-time user, I'd expect them to be SOL and stuck spending a Linux evening digging through the Nix manuals to figure out how to configure their system. (I just checked, and "First steps with Nix" starts with "Ad hoc shell environments", not anything to do with `/etc/nixos/configuration.nix`)

If they're a DevOps user who's going to be using it for every day of their job, that's probably time well spent; but if they're a casual user who only wants to maintain the same set of software and settings whenever they get a new computer, it may just be more time-efficient to go through some pain every several years.

For even a power user, they probably need to be working with a lot of software projects with native dependencies, or switching between computers a lot. Or just specifically curious about Nix.

But in any case, I very much disagree that it's just an out-of-date reputation that's holding Nix back. Its functionality is really, really useful and widespread adoption would make language-specific tools somewhat redundant (eg virtualenv). I'm pretty sure the main thing holding it back is that it's just too hard to use and people silently abandon it.

> I just checked, and "First steps with Nix" starts with "Ad hoc shell environments", not anything to do with `/etc/nixos/configuration.nix`

So many people get started with Nix, not NixOS. Once see how useful it is, they then begin migrating their existing systems over to NixOS.

Not only that, but ad hoc shell environments are one the most common use cases. Putting that in the forefront of the official documentation is helpful. I also somehow can't help but think that if the official documentation followed your advice and started off with configuration.nix before explaining the Nix basics, you'd have a problem with that just the same.

> btrfs being unstable persists for a couple of reasons

Fedora uses it by default as does openSUSE. Meta uses it for thousands of their own servers. The very specific RAID configuration is a non-issue for 99.9 percent of people. If they have need of it they'll use something else.

> I'm pretty sure the main thing holding it back is that it's just too hard to use and people silently abandon it.

That's why you use the tools to make it easy. Use the Determinate Nix installer, then install Fleek. I haven't read the Nix manual in at least 5 years.

> But for any first-time user, I'd expect them to be SOL and stuck spending a Linux evening digging through the Nix manuals to figure out how to configure their system. (I just checked, and "First steps with Nix" starts with "Ad hoc shell environments", not anything to do with `/etc/nixos/configuration.nix`)

What? This is not what most users will be doing, no.

> What? This is not what most users will be doing, no.

Yeah, but that's what the Nix website has.

https://nixos.org/

Let's assume I already know I want to try Nix, but I don't know anything about it. I probably either:

(1) Click "Download" (https://nixos.org/download) (2) Click "Get Started" (https://nixos.org/learn), then "Install Nix" (https://nixos.org/download#download-nix)

Either way, those instructions don't offer any clear next step. I might get it installed, but what now?

Going back to "Get Started" (https://nixos.org/learn), the next options is "First steps with Nix" (https://nix.dev/tutorials/first-steps/). The options here are:

    Ad hoc shell environments
    Reproducible interpreted scripts
    Towards reproducibility: pinning Nixpkgs
    Declarative shell environments with shell.nix
None of which covers what you'd probably want to do after you've freshly installed Nix or NixOS, eg system configuration and package management.

Having officially ordained instructions isn't just a convenience for n00bs, it's also useful for knowing what needs to be maintained whenever there are changes, and consolidating effort to continually improve upon the presentation (rather than everybody having their own blog post just from their perspective).

> The very specific RAID configuration is a non-issue for 99.9 percent of people

"Very specific" being the most common RAID configuration used outside of personal computing (when you have more than 2-3 disks, you aren't running RAID1/RAID0/RAID10, it's all RAID 5/6). And funnily, one of the main scenarios where an advanced filesystem is actually genuinely needed and not just a nice to have, is when you have lots of disks.

I don't buy the "just use X or Y" either. It's like "just use ohmyzsh".

That's why I use dead simple nix stuff, which gets me 90% of the way (more like 140% if compared to Homebrew). If one's goal is to replace - and solve a few problems inherent to - homebrew or apt it's really not hard, see my sibling comment.

I disagree and that's why I recommended Fleek. What is dead simple to you about Nix is not dead simple to others. Especially given your other comment: it's filled with Nix-isms that most people used to imperative thinking would not grok.
> it's filled with Nix-isms

Which part?

For the commands, update install upgrade uninstall are straight the same.

There's an additional -A on install, but you don't need to understand it. The commands are even handed over to you on https://search.nixos.org/packages.

There's an additional nixpkgs prefix but it's perfectly understandable that it's coming from the channel name:

    # nix-channel --list
    nixpkgs https://nixos.org/channels/nixpkgs-23.05-darwin
It's really not out of this world to mentally map this to homebrew taps or apt repos.

nix-env --query is different from homebrew but its design is much the same as pacman -Q and people have no trouble with that (I won't even dive on apt-get vs dpkg vs apt-cache)

nix-env -f <github archive url> --install nixos-23.05.tar.gz is such because it's the branch name, 88f63d51109.tar.gz is just the commit sha. These are GitHub things. Providing the source of packages as a --file option is hardly inscrutable nor even a nix-only thing.

But if you really want a parallel with homebrew, then homebrew has taps, and nixpkgs has channels: nix-channel --add <url> name is directly equivalent to brew tap user/repo <url>, down to installing with brew install user/repo/package vs nix-env --install -A name.package.

And there it is, you have your 1:1 nixism-free homebrew:nixpkgs replacement, and can manage your packages with nix just like you do with homebrew.

> there's now a large quantity of tooling that makes it as easy to work with as Homebrew

My point is that there is no tool that could "make it as easy to work with as homebrew" because homebrew:nixpkgs is already 1:1, and people confused by using nix this way would equally be confused by using homebrew.

You mentioned Fleek, which seems like a nice tool, but managing home is outside the scope of homebrew so I don't see how it follows that it makes nix "as easy as homebrew". It apparently has some homebrew bits, but it's a third party tool to both homebrew and nix.

Don't get me wrong, tools can be nice, I use nix-darwin myself, not too sure about going home-manager yet.

---

Now that second part where I talk about shell.nix, maybe it's this one you took issue with? I aimed it at being a next step, not addressing the above point, but attempting to demonstrate the immediate value it can give without understanding the slightest bit of nix and especially eschewing all the nix-specific vernacular.

The first time it is encountered, this is probably what a reasonable non-nixer vaguely interested in would see:

    {
      pkgs ? import <nixpkgs> {},
      # ^^^^^^^^^^^^^^^^^^^^^^^^
      # okay so I've seen nixpkgs before, that's my channel, where the packages come from
      # that `?` looks odd but well, whatever, there's a "pkgs" thing and an import of sorts.
    }:
    pkgs.mkShell {
    # ^^^^^^^^^^
    # this is:
    # - a shell.nix file
    # - that has been described to me as being used by a `nix-shell` command
    # - and that thing is name mkShell
    # so probably it's going to tell things how to make that shell
      buildInputs = [
        pkgs.ruby_3_2;
        # here's that pkgs that I've seen above
        # it has a dot plus a package name just like when I did nix-env --install
        # except it had nixpkgs before the dot there
        # oh, I see "pkgs ? import ..." sort of creates that variable or whatever from nixpkgs
        # so this is a list of packages from nixpkgs
      ];
      # and so that make a shell thing uses that list to get its dependencies
      # and it's getting named buildInputs, whatever
    }
    # so that's it, it makes a shell using a list of packages from nixpkgs
And proceed to add whatever package they see fit by looking them up on the search page. Understanding of nixisms doesn't matter.

Second example: "let .. in" isn't a very special nix construct, "let" is extremely frequently used in a number of languages (including JS) to define variables. "whatever .. in" is a very common construct as well. It's quite obvious that the example hoists out a few elements by assigning variables between "let" and "in", possibly creating some form of scope after "in". It also introduces "shellHook", which literally contains a multiline bash string; again I feel like it's quite obvious that the "make shell" thingy is going to call that hook at some point.

Last bits shows that the nixpkgs channel can be replaced with fetchTarball + a GitHub tarball archive URL, and that you can have multiple of these at once with different names, referencing packages from one or the other.

> that most people used to imperative thinking would not grok.

I can hear that the syntax is an oddball, but even then that example is really not that hard to wrap one's head around for anyone who has a passing familiarity with programming, whether functional or imperative.

Doesn't mean that they would fully appreciate that { foo ? "bleh" }: whatevs = 42 is actually a function definition equivalent to JS function(foo = "bleh") { return { "whatevs": 42 }; } but that's immaterial to understanding what is happening here and even being able to add/remove packages, change versions, pin sources, or hack that shell bit and ultimately have it be pragmatically useful.

So I don't think the nixisms are any problem in this case because they can be completely ignored. I'm also wondering if people have an epidermic reaction to the syntax, combined with the constant rumour that nix is hard and hardly usable does not set them up for success.

I mean, would people be as hung up if it were written this way?

   args:
     pkgs: <nixpkgs>
   let:
     ruby: pkgs.ruby_3_2;
     whatevs: pkgs.whatevs42;
   in:
     pkgs.mkShell:
       buildInputs:
         - ruby
         - whatevs
         - pkgs.foobar
       shellHook: |
          export RUBY_VERSION="$(ruby -e 'puts RUBY_VERSION.gsub(/\d+$/, "0")')"
          export GEM_HOME="$(pwd)/vendor/bundle/ruby/$RUBY_VERSION"
          export BUNDLE_PATH="$(pwd)/vendor/bundle"
          export PATH="$GEM_HOME/bin:$PATH"
or this way?

    function(pkgs = import(NixPath.resolve('nixpkgs'))) {
      let ruby = pkgs.ruby_3_2;
      let whatevs = pkgs.whatevs42;
    
      return pkgs.mkShell({
        buildInputs: [
          ruby,
          whatevs,
          pkgs.foobar,
        ],
        shellHook: `
          export RUBY_VERSION="$(ruby -e 'puts RUBY_VERSION.gsub(/\d+$/, "0")')"
          export GEM_HOME="$(pwd)/vendor/bundle/ruby/$RUBY_VERSION"
          export BUNDLE_PATH="$(pwd)/vendor/bundle"
          export PATH="$GEM_HOME/bin:$PATH"
        `
      });
    }
Because at the end of the day, it's not that different in complexity, from, say, a Gemfile, a PKGBUILD, or a homebrew formula.
Regarding your last point, I actually do think that if the syntax to nix were different that it would make it much easier to understand. Though, the fact that it is clearly distinct from, say, Python or JavaScript gives it its own distinct feel as to how 'rigid' it is.

To me the big stumbling block in the language is that it at first appears declarative, like you're writing a data structure that describes your configuration. However, when you start modifying anything about packages, you need to call functions to make changes because you're actually writing a function that's transforming input.

So, you're thinking about what you're trying to do in a declarative, descriptive sense and certain parts of what you're writing are structured as such; but then other parts are structured as a transformation.

Eg you write out a list of packages, but then if you want to change one of those packages, you need to start calling functions. As I mentioned in the Python example below, that can wind up requiring calling `override`, `overrideAttrs`, `overridePythonAttrs`, etc.

Consider this:

  {
    packageOverrides = pkgs: {
      python3 = pkgs.python3.override {
        packageOverrides = python-self: python-super: {
          twitch-python = python-super.twitch-python.overrideAttrs (attrs: {
            patches = (attrs.patches or []) ++ [
              ./twitch-allow-no-token.patch
            ];
          });
        };
      };

      twitch-chat-downloader = pkgs.twitch-chat-downloader.overrideAttrs (attrs: {
        patches = (attrs.patches or []) ++ [
          ./twitch-chat-downloader-no-oauth.patch
        ];
      });
    };
  }

Versus this:

  {
    packageOverrides: pkgs {
      python3: {
        twitch-python: pkgs.python3.twitch-python {
          patches: pkgs.python3.twitch-python.patches or ./twitch-allow-no-token.patch
        }
      },
      twitch-chat-downloader: pkgs.twitch-chat-downloader {
        patches: pkgs.twitch-chat-downloader.patches or ./twitch-chat-downloader-no-oauth.patch
      }
  }
The latter is less "functionally perfect", but there is vastly less cognitive overhead required to lay it out because you are basically just describing your goal, rather than having to keep your goal in mind while implementing it functionally (and keeping exactly how nixpkgs is implemented in mind to correctly use those overrides).

This is just off-the-cuff of what I intuitively expected when I first started using Nix, but it's more what I'd expect of a no-holds-barred purpose-built language for declarative package management. All the override stuff seems like needlessly noisy syntax; you know it's going to be everywhere, you might as well build it into the language.

And it can probably be made even simpler with effort.

> To me the big stumbling block in the language is that it at first appears declarative, like you're writing a data structure that describes your configuration. However, when you start modifying anything about packages, you need to call functions to make changes because you're actually writing a function that's transforming input.

That's a very fair point to make. I have noticed the same and it seems like it's borne out of the way Nix (NixOS more precisely) is built, which is in two layers:

- a first layer of packages and whatnot, which is by and large functional programming, and has the gritty implementation you mention which get exposed when you want to alter some specific things

- a second layer of configuration modules, which takes packages and turns them into a declarative interface

From a Ruby analogy I would compare the first to some form of monkey-patching or otherwise forceful injection and the second one to a nice DSL which exposes clear properties to change some bits

For example, on modules there's `.package` which allows one to override the package to use fairly easily:

  services.tailscale.enable = true;
  services.tailscale.package = let
    old = import(fetchTarball("https://github.com/NixOS/nixpkgs/archive/a695c109a2c.tar.gz")) {};
  in
    old.tailscale;
(taken from this issue https://github.com/NixOS/nixpkgs/issues/245769)

Frequently you get additionalPackages or extraConfig or something in this "DSL", which handles the whacky non-descriptive stuff behind the scenes which really is an implementation detail that should not leak through.

So indeed I feel like Nix packages in general should benefit from a more descriptive interface similar to what NixOS modules expose, so that appending patches or adding configure flags would not be such an ordeal.

Basically this (pseudocode) should be generalised and hidden away:

      # iterate over patch map => mypackage, mypatches
        packageOverrides = python-self: python-super: {
          ${mypackage} = python-super.${mypackage}.overrideAttrs (attrs: {
            patches = (attrs.patches or []) ++ ${mypatches};
          });
        };
So you then would just descriptively pass python3.packagePatches = { twitch-python = [./twitch-allow-no-token.patch] } or something and be done with it. Not saying it's easy for Nix folks to achieve that but it should be doable one way or another. I mean, there's already:

      python_packages = python-packages: [
        python-packages.pip
      ];
      python = pkgs.python39.withPackages python_packages;
It's not out of this world to think there chould be a generalisable extension of that for patches (and more) to fill in the various overrides that exist around Nix derivations.

That would certainly make nixpkgs more approachable.