Nixpkgs

What is nixpkgs?

A collection of Nix utility functions, modules, and packages.
Contains build-system abstractions to build packages
Contains abstractions to build build-system abstractions

❤ (theia) ~/P/nixpkgs> ls
CONTRIBUTING.md  default.nix  flake.nix  maintainers/  pkgs/
COPYING          doc/         lib/       nixos/        README.md

 ❤ (theia) ~/P/nixpkgs> ls pkgs/
applications   common-updater  desktops  games  os-specific  servers
stdenv  tools  build-support   data      development  misc   pkgs-lib
shells  test   top-level

 ❤ (theia) ~/P/nixpkgs> ls nixos/modules
config  hardware  i18n  installer  misc  module-list.nix  profiles
programs  rename.nix  security  services  system  tasks  testing
virtualisation

pkgs/top-level/all-packages.nix

{
  # ...
  
  hdr-plus = callPackage ../applications/graphics/hdr-plus {
    stdenv = clangStdenv;
  };
  
  heimer = libsForQt5.callPackage ../applications/misc/heimer { };
  hello = callPackage ../applications/misc/hello { };
  
  # ...
}

Note: default.nix is loaded from directories automatically.

`callPackage` tangent

ncdu = callPackage ../tools/ncdu/default.nix { };

{ lib, stdenv, fetchurl, zig, ncurses }:

stdenv.mkDerivation rec {
  pname = "ncdu";
  ...
}

Introspect what parameters a package requires
Then call the package function with only those parameters
Implemented in lib/customisation.nix (if you’re curious how it works)

Yes, you can use it yourself

callPackage performs some magic which you may want to opt-into

Load <nixpkgs>
Invoke callPackage with your package definition
A package definition consists of a function which accepts an attribute set and returns a derivation
Parameter attribute set must not include { ... }
Pass an additional attribute set with configuration to callPackage (can be { })

with import <nixpkgs> { };
callPackage
  { lib, stdenv, fetchurl, zig, ncurses }: stdenv.mkDerivation {
    pname = "ncdu";

    ...
  }
    { }

Why?

Slighly nicer package definition (no need to figure out where packages are defined)
Easier cross-compilation!

with import <nixpkgs> {
  crossSystem = (import <nixpkgs/lib>).systems.examples.aarch64-multiplatform // {
    rustc.config = "aarch64-linux-gnu";
  };
};
callPackage ( ... ) { }

 ❤ (theia) ~> nix-build ./call-package.nix
this derivation will be built:
  /nix/store/6zw0104k6nm0vrmvdx1bpwd1jarjhghd-ncdu-aarch64-unknown-linux-gnu-2.2.1.drv
these 19 paths will be fetched (43.16 MiB download, 224.03 MiB unpacked):
...
 ❤ (theia) ~> file ./result/bin/tokei
/nix/store/xs7vbi3g48x7f25byvx4hjy5as27hqr9-tokei-aarch64-unknown-linux-gnu-12.1.2/bin/tokei:
ELF 64-bit LSB pie executable, ARM aarch64, version 1 (SYSV), dynamically linked, interpreter
/nix/store/xzk2l5c6nmr0qskyij1jvbpsv9a1b7ky-glibc-aarch64-unknown-linux-gnu-2.35-163/lib/ld-linux-aarch64.so.1,
for GNU/Linux 2.6.32, not stripped

stdenv

A common build environment for packages

gccStdenv
clangStdenv
gcc10.stdenv
gcc-arm-embedded.stdenv
llvm-13.stdenv
…

Extending stdenv

{ lib, stdenv, fetchurl }:
stdenv.mkDerivation rec {
  pname = "hello";
  version = "2.10";

  src = fetchurl {
    url = "mirror://gnu/hello/${pname}-${version}.tar.gz";
    sha256 = "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i";
  };
  
  doCheck = true;
  
  # ...snip...
}

Pre	Phase	Post
preUnpack	unpackPhase	postUnpack
prePatch	patchPhase	postPatch
preConfigure	configurePhase	postConfigure
preBuild	buildPhase	postBuild
preCheck	checkPhase	postCheck
preInstall	installPhase	postInstall
preFixup	fixupPhase	postFixup
preInstallCheck	installCheckPhase	postInstallCheck
preDist	distPhase	postDist

Any phase can easily be extended

{
  # ...

  postPatch = ''
    substituteInPlace alacritty/src/config/mouse.rs \
      --replace "xdg-open" "${xdg_utils}/bin/xdg-open"
  '';
}

Any extra keys become ENV variables

stdenv.mkDerivation {
  CRASH_REPORTER = "${my_crash_reporter}/bin/boom";
  
  # ...
}

buildGoPackage rec {
  # ...

  patches = [ ./0001-Disable-NIC-tests.patch ];
  
  configurePhase = ''
    substituteInPlace agent/platform/platform_unix.go \
      --replace '"lsb_release"' '"${lsb-release}/bin/lsb_release"'
    echo "${version}" > VERSION
  '';
  
  buildPhase = ''
    make build-linux
  '';
  
  installPhase = ''
    mkdir -p $out/bin
    mv bin/linux_*/* $out/bin/
  '';
}

Package sets

Some collections of packages are treated as a `set`
For example: any language specific package ecosystem

let
  pythonDeps = with python3Packages; [ zeek zstd netio ];
in stdenv.mkDerivation {
  name = "my-app";

  buildInputs = [ pkgs.python3 ] ++ pythonDeps;

  # ...
}

Alternatively

let myPython = pkgs.python3.withPackages 
  (pypkgs: with pypkgs; [
    zeek zstd netio
  ]);
in
stdenv.mkDerivation {
  name = "my-app";
  
  buildInputs = [ myPython ];
}

Package sets are everywhere

python3Packages and python3.withPackages
rubyPackages and ruby.withPackages
emacsPackages and emacs.withPackages
haskellPackages (but no withPackages)
perlPackages and perl.withPackages
…

How do these work?

let
  pkgs = import <nixpkgs> { };
in
  pkgs.python3.withPackages
    (pypkgs: with pypkgs; [ zeek zstd netio ])

❤ (theia) ~> nix-build pkgs/specific-python.nix

 ❤ (theia) ~> tree result/ -L 2
result/
├── bin
│   ├── 2to3
│   ├── 2to3-3.10
│   ├── bifcl -> /nix/store/djbzvch3scq8y125247r0qkx95ynzxxq-zeek-4.2.2/bin/bifcl
│   ├── binpac -> /nix/store/djbzvch3scq8y125247r0qkx95ynzxxq-zeek-4.2.2/bin/binpac
│   │   .........
│   ├── Netio
│   ├── normalizer
│   ├── paraglob-test -> /nix/store/djbzvch3scq8y125247r0qkx95ynzxxq-zeek-4.2.2/bin/paraglob-test
│   ├── pydoc3.10
│   ├── python3.10
│   ├── zeek -> /nix/store/djbzvch3scq8y125247r0qkx95ynzxxq-zeek-4.2.2/bin/zeek
│   ├── zeek-config -> /nix/store/djbzvch3scq8y125247r0qkx95ynzxxq-zeek-4.2.2/bin/zeek-config
│   ├── zeek-cut -> /nix/store/djbzvch3scq8y125247r0qkx95ynzxxq-zeek-4.2.2/bin/zeek-cut
│   └── zeek-wrapper -> /nix/store/djbzvch3scq8y125247r0qkx95ynzxxq-zeek-4.2.2/bin/zeek-wrapper
├── include
│   ├── binpac -> /nix/store/djbzvch3scq8y125247r0qkx95ynzxxq-zeek-4.2.2/include/binpac
│   ├── broker -> /nix/store/djbzvch3scq8y125247r0qkx95ynzxxq-zeek-4.2.2/include/broker
│   ├── paraglob -> /nix/store/djbzvch3scq8y125247r0qkx95ynzxxq-zeek-4.2.2/include/paraglob
│   ├── python3.10 -> /nix/store/9wa02q541sxq7372f8zv27rl57aribxj-python3-3.10.5/include/python3.10
│   └── zeek -> /nix/store/djbzvch3scq8y125247r0qkx95ynzxxq-zeek-4.2.2/include/zeek
├── lib
│   ├── libpython3.10.so -> /nix/store/9wa02q541sxq7372f8zv27rl57aribxj-python3-3.10.5/lib/libpython3.10.so
│   ├── libpython3.10.so.1.0 -> /nix/store/9wa02q541sxq7372f8zv27rl57aribxj-python3-3.10.5/lib/libpython3.10.so.1.0
│   ├── libpython3.so -> /nix/store/9wa02q541sxq7372f8zv27rl57aribxj-python3-3.10.5/lib/libpython3.so
│   ├── pkgconfig -> /nix/store/9wa02q541sxq7372f8zv27rl57aribxj-python3-3.10.5/lib/pkgconfig
│   └── python3.10
└── share
    ├── btest -> /nix/store/djbzvch3scq8y125247r0qkx95ynzxxq-zeek-4.2.2/share/btest
    ├── gdb -> /nix/store/9wa02q541sxq7372f8zv27rl57aribxj-python3-3.10.5/share/gdb
    ├── man
    └── zeek -> /nix/store/djbzvch3scq8y125247r0qkx95ynzxxq-zeek-4.2.2/share/zeek

 ❤ (theia) ~> ls -l result/lib/python3.10/site-packages/
total 28
lrwxrwxrwx 1 root root  93 Jan  1  1970 broker -> /nix/store/b1rw2gbcjz5r6n0cm7jfy4gqbji11fqn-zeek-4.2.2-py/lib/python3.10/site-packages/broker
lrwxrwxrwx 1 root root 119 Jan  1  1970 Brotli-1.0.9.dist-info -> /nix/store/dn035bna0m6fnrxq64v0x245r2cs7l1z-python3.10-brotli-1.0.9/lib/python3.10/site-packages/Brotli-1.0.9.dist-info
lrwxrwxrwx 1 root root 113 Jan  1  1970 brotlicffi -> /nix/store/3ppyd1zrvpk0n7c55kmdygcapn73hnv1-python3.10-brotlicffi-1.0.9.2/lib/python3.10/site-packages/brotlicffi
lrwxrwxrwx 1 root root 131 Jan  1  1970 brotlicffi-1.0.9.2.dist-info -> /nix/store/3ppyd1zrvpk0n7c55kmdygcapn73hnv1-python3.10-brotlicffi-1.0.9.2/lib/python3.10/site-packages/brotlicffi-1.0.9.2.dist-info
lrwxrwxrwx 1 root root 136 Jan  1  1970 _brotli.cpython-310-x86_64-linux-gnu.so -> /nix/store/dn035bna0m6fnrxq64v0x245r2cs7l1z-python3.10-brotli-1.0.9/lib/python3.10/site-packages/_brotli.cpython-310-x86_64-linux-gnu.so
lrwxrwxrwx 1 root root 106 Jan  1  1970 brotli.py -> /nix/store/dn035bna0m6fnrxq64v0x245r2cs7l1z-python3.10-brotli-1.0.9/lib/python3.10/site-packages/brotli.py
...................
lrwxrwxrwx 1 root root 119 Jan  1  1970 zstd-1.5.2.5.dist-info -> /nix/store/xss74rs462bm8c00m50m3f63b1lcxfn7-python3.10-zstd-1.5.2.5/lib/python3.10/site-packages/zstd-1.5.2.5.dist-info
lrwxrwxrwx 1 root root 133 Jan  1  1970 zstd.cpython-310-x86_64-linux-gnu.so -> /nix/store/xss74rs462bm8c00m50m3f63b1lcxfn7-python3.10-zstd-1.5.2.5/lib/python3.10/site-packages/zstd.cpython-310-x86_64-linux-gnu.so

Tangent: my emacs config

self: super: {
  buildEmacsWithPlan =  plan:
    self.pkgs.emacs-gtk.pkgs.withPackages (epkgs:
      let
        builder = import ./builder.nix self;
        includeOne = path: (import path {
          inherit (self) pkgs;
          buildModule = builder.buildModule;
          epkgs = self.emacsPackages;
        });
   
        elib = { ## This is an attribute set because we MAY want to
                 ## expand it in the future!
          buildModuleTree = modules: (builder.bootstrap (map (p: includeOne p) modules));
        };
      in
        ## Load the plan.nix file and select the provided plan
        ((import ./plans.nix self)."${plan}" elib epkgs));

https://cyberchaos.dev/kookie/kookie.el

export EMACSLOADPATH="${newLoadPath[*]}"
export emacsWithPackages_siteLisp=/nix/store/xpxy7j1f9qp16jgziwm5s3pdhvckfdbh-emacs-packages-deps/share/emacs/site-lisp

export EMACSNATIVELOADPATH="${newNativeLoadPath[*]}"
export emacsWithPackages_siteLispNative=/nix/store/xpxy7j1f9qp16jgziwm5s3pdhvckfdbh-emacs-packages-deps/share/emacs/native-lisp:

exec /nix/store/2lxx8irdiwk3jj1zm743m4xd276r5f1h-emacs-28.1/bin/emacs "$@"

 ❤ (theia) ~> ls -l /nix/store/xpxy7j1f9qp16jgziwm5s3pdhvckfdbh-emacs-packages-deps/share/emacs/site-lisp
total 34
lrwxrwxrwx  1 root root    81 Jan  1  1970 base.el -> /nix/store/wr5g5lk000lf7wchs79y0gp4p7jlgizf-base.el/share/emacs/site-lisp/base.el
lrwxrwxrwx  1 root root    87 Jan  1  1970 default.el -> /nix/store/jy0s5rf0i4r7f2cwsxbbahk4djsfrssr-default.el/share/emacs/site-lisp/default.el
dr-xr-xr-x 73 root root    73 Jan  1  1970 elpa
lrwxrwxrwx  1 root root   101 Jan  1  1970 kookie-notmuch.el -> /nix/store/nrq4z9l6d30li602nv7lrvbfrzc3dqiv-kookie-notmuch.el/share/emacs/site-lisp/kookie-notmuch.el
lrwxrwxrwx  1 root root    93 Jan  1  1970 kookie-org.el -> /nix/store/j55sjmv454q9vlhyglhfjd0mr8zs2ls0-kookie-org.el/share/emacs/site-lisp/kookie-org.el
lrwxrwxrwx  1 root root    93 Jan  1  1970 move-lines.el -> /nix/store/f9wd669sndaa14l6byir62ia09c258gv-move-lines.el/share/emacs/site-lisp/move-lines.el
lrwxrwxrwx  1 root root    97 Jan  1  1970 multi-cursor.el -> /nix/store/l3nkc3d2jj2gzpzmhj4swcs2bilj7i9i-multi-cursor.el/share/emacs/site-lisp/multi-cursor.el
lrwxrwxrwx  1 root root    95 Jan  1  1970 notmuch-logo.svg -> /nix/store/z7xh2h5jgqwfv05a8fakcf4869qax20v-notmuch-0.36/share/emacs/site-lisp/notmuch-logo.svg
lrwxrwxrwx  1 root root    99 Jan  1  1970 notmuch-rules.el -> /nix/store/qr6if0qj9mzn0hvzw1cc0lzf2q01glpx-notmuch-rules.el/share/emacs/site-lisp/notmuch-rules.el
lrwxrwxrwx  1 root root    81 Jan  1  1970 rust.el -> /nix/store/dqv30db78wc1fyb199l0gxjslcbg5s0c-rust.el/share/emacs/site-lisp/rust.el
-r--r--r--  1 root root   344 Jan  1  1970 site-start.el
-r--r--r--  1 root root   464 Jan  1  1970 site-start.elc
-r--r--r--  1 root root 10403 Jan  1  1970 subdirs.el
-r--r--r--  1 root root 10507 Jan  1  1970 subdirs.elc
lrwxrwxrwx  1 root root    83 Jan  1  1970 theme.el -> /nix/store/75dsm2imngw7949jlpwmizhgvw2k3zx5-theme.el/share/emacs/site-lisp/theme.el

Manuals

Nix (language & CLI): https://nixos.org/manual/nix/
nixpkgs: https://nixos.org/manual/nixpkgs/
NixOS: https://nixos.org/manual/nixos/

build-support

Found in nixpkgs/pkgs/build-support
Basic utilities for building packages
Language-specific build environments (but not all of them)
- The rest might be in pkgs/development or pkgs/top-level/<language>-packages.nix

fetchurl

Most basic fetcher
Downloads the target URL and checks against the checksum

fetchurl {
  url = "https://mirror.httrack.com/httrack-3.49.2.tar.gz";
  sha256 = "09a0gm67nml86qby1k1gh7rdxamnrnzwr6l9r5iiq94favjs0xrl";
};

fetchTarball

Specifically wants to download a .tar archive
Will unpack sources automatically
Changing from fetchurl to fetchTarball will change the hash!

fetchTarball {
  name = "httrack-";
  url = "https://mirror.httrack.com/httrack-3.49.2.tar.gz";
  sha256 = "0dzdw4z639iakay3270valmzc84galj6jg0my4iw0axlr5d6rx8b";
}

`fetch(From)\(Git)\[Hub|Lab|ea]\*`

Specifically will clone a git revision

fetchFromGitHub { ... }

fetchFromGitLab { ... }

fetchFromGitea { ... }

...

writeScript

The '' syntax is great for in-line shell scripts

let
  pkgs = import <nixpkgs> { };
in
  pkgs.writeScript "work-git"
    ''
      #!${pkgs.bash}/bin/bash
      ${pkgs.git}/bin/git \
        -c commit.gpgSign=false \
        -c user.email="kookie@spacekookie.de" \
        "$@"
    ''

 ❤ (theia) ~> nix-build pkgs/write-script.nix
this derivation will be built:
  /nix/store/dvpm6mvfqqgy63mhm8syixxbmchdb8h7-work-git.drv
building '/nix/store/dvpm6mvfqqgy63mhm8syixxbmchdb8h7-work-git.drv'...
/nix/store/h05lmbsryl419ygqck671k24kffw1nlg-work-git

 ❤ (theia) ~>  ./result
usage: git [-v | --version] [-h | --help] [-C <path>] [-c <name>=<value>]
           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
           [-p | --paginate | -P | --no-pager] [--no-replace-objects] [--bare]

writeText

let
  pkgs = import <nixpkgs> { };
in
  pkgs.writeText "work-git-conf"
    ''
      [commit]
        gpgSign = false
      [user]
        email = "kookie@spacekookie.de"
    ''

 ❤ (theia) ~> nix-build pkgs/write-text.nix
this derivation will be built:
  /nix/store/6w2d1ci1gm8kzraayjv08s0p0aysmhsx-work-git-conf.drv
building '/nix/store/6w2d1ci1gm8kzraayjv08s0p0aysmhsx-work-git-conf.drv'...
/nix/store/clva7rs7hnlwrxz50b22y14cjpz6kja9-work-git-conf

 ❤ (theia) ~> cat result
[commit]
  gpgSign = false
[user]
  email = "kookie@spacekookie.de"

More at https://nixos.org/manual/nixpkgs/stable/#trivial-builder-writeText

let
  pkgs = import <nixpkgs> { };
  conf = pkgs.writeText "work-git-conf"
    ''
      [commit]
      gpgSign = false
      [user]
      email = "kookie@spacekookie.de"
    '';
in
  pkgs.writeScript "work-git"
    ''
      #!${pkgs.bash}/bin/bash
      ${pkgs.git}/bin/git -c include.path="${conf}" "$@"
    ''

`writeText` is just a wrapper!

writeText = name: text: writeTextFile { inherit name text; };

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10-nixpkgs.org

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Nixpkgs

What is nixpkgs?

pkgs/top-level/all-packages.nix

`callPackage` tangent

Yes, you can use it yourself

Why?

stdenv

Extending stdenv

Any phase can easily be extended

Any extra keys become ENV variables

Package sets

Alternatively

Package sets are everywhere

How do these work?

Tangent: my emacs config

Manuals

build-support

fetchurl

fetchTarball

`fetch(From)\(Git)\[Hub|Lab|ea]\*`

writeScript

writeText

`writeText` is just a wrapper!

Push work to build time

Back to index

Files

10-nixpkgs.org

Latest commit

History

10-nixpkgs.org

File metadata and controls

Nixpkgs

What is nixpkgs?

pkgs/top-level/all-packages.nix

callPackage tangent

Yes, you can use it yourself

Why?

stdenv

Extending stdenv

Any phase can easily be extended

Any extra keys become ENV variables

Package sets

Alternatively

Package sets are everywhere

How do these work?

Tangent: my emacs config

Manuals

build-support

fetchurl

fetchTarball

fetch(From)\*(Git)\*[Hub|Lab|ea]\*

writeScript

writeText

writeText is just a wrapper!

Push work to build time

Back to index

`callPackage` tangent

`fetch(From)\(Git)\[Hub|Lab|ea]\*`

`writeText` is just a wrapper!