+++
date    = "2023-01-06T03:23:42+00:00"
lastmod = "2023-08-25T03:46:56+00:00"
tags    = [ "linux", "gists" ]
author  = "tdro"
+++

{{< disclose >}}
My default
[`nix`](https://nixos.org/manual/nix/stable/command-ref/conf-file.html?highlight=nix.conf)
configuration on [NixOS](https://nixos.org/).
{{</ disclose >}}

This configuration is more for building/debugging stuff and caching with
[`nix-serve`](https://nixos.org/manual/nix/stable/package-management/binary-cache-substituter.html).
Usually my package version is locked since different
[versions](https://nixos.org/manual/nix/stable/release-notes/rl-2.17.html) of
`nix` can have some effects.

```nix {caption="My nix-configuration.nix on version 23.05"}
{ config, ... }:

{
  nix = {
    package = (import ../versions.nix).nix_2_17 { inherit config; };
    settings = {
      log-lines = 25;                                # https://nixos.org/manual/nix/unstable/command-ref/conf-file.html#conf-log-lines
      fallback = true;                               # https://nixos.org/manual/nix/unstable/command-ref/conf-file.html#conf-fallback
      tarball-ttl = 0;                               # https://nixos.org/manual/nix/unstable/command-ref/conf-file.html#conf-tarball-ttl
      show-trace = true;                             # https://nixos.org/manual/nix/unstable/command-ref/conf-file.html#conf-show-trace
      connect-timeout = 5;                           # https://nixos.org/manual/nix/unstable/command-ref/conf-file.html#conf-connect-timeout
      auto-optimise-store = true;                    # https://nixos.org/manual/nix/unstable/command-ref/conf-file.html#conf-auto-optimise-store
      narinfo-cache-negative-ttl = 0;                # https://nixos.org/manual/nix/unstable/command-ref/conf-file.html#conf-narinfo-cache-negative-ttl
      narinfo-cache-positive-ttl = 0;                # https://nixos.org/manual/nix/unstable/command-ref/conf-file.html#conf-narinfo-cache-positive-ttl
      builders-use-substitutes = true;               # https://nixos.org/manual/nix/unstable/command-ref/conf-file.html#conf-builders-use-substitutes
      min-free = 268435456;                          # https://nixos.org/manual/nix/unstable/command-ref/conf-file.html#conf-min-free (256 MB in Bytes)
      max-free = 1073741824;                         # https://nixos.org/manual/nix/unstable/command-ref/conf-file.html#conf-max-free (1 GB in Bytes)
      allowed-users = [ "root" "@wheel" ];           # https://nixos.org/manual/nix/unstable/command-ref/conf-file.html#conf-allowed-users
      trusted-users = [ "root" "@wheel" ];           # https://nixos.org/manual/nix/unstable/command-ref/conf-file.html#conf-trusted-users
      experimental-features = "nix-command flakes";  # https://nixos.org/manual/nix/unstable/command-ref/conf-file.html#conf-experimental-features
    };
  };
}
```