☎️ 🔄 ♓️ Nix: O que é e com o que devo usá-lo? 🎻 🚯 💗

Olá, Habr!

Nós da Typeable queríamos publicar uma pequena série de artigos sobre como o Nix nos ajuda (e nos atrapalha um pouco) no desenvolvimento. Mas depois de passar algum tempo procurando por material semelhante aqui, ficamos surpresos ao descobrir que não há uma introdução sensata a Nix em Habré à qual se possa referir.

@snizovtsev C++, , . :)

?

NixOS, , Nix ( ) Linux. :

$ sh <(curl -L https://nixos.org/nix/install)

. MacOS, , . MacOS .

Nix

Nix, : Nix nixpkgs , NixOS. .

Nix — . ML (SML, OCaml, Haskell), , , .

$ nix repl
Welcome to Nix version 2.3.10. Type :? for help.

nix-repl>

Nix . , .

nix-repl> "Hello " + "World!"
"Hello World!"

nix-repl> add = a: b: a + b

nix-repl> add 1 2
3

, Nix, .

nix-repl> addOne = add 1

nix-repl> addOne 3
4

, , Nix (attribute sets Nix).

nix-repl> list = [ 1 2 3 ]

nix-repl> set = { a = 1; b = list; }     

nix-repl> set
{ a = 1; b = [ ... ]; }

nix-repl> set.b
[ 1 2 3 ]

let...in

. , , , .

fac.nix

:

let
  fac = n:
    if n == 0
    then 1
    else n * fac (n - 1);
in { inherit fac; }

inherit

"" . let fac = ... in { fac = fac; }

.

$ nix repl fac.nix
Welcome to Nix version 2.3.10. Type :? for help.

Loading 'fac.nix'...
Added 1 variables.

nix-repl> fac 3 
6

REPL, Nix , , .

Nix import

, .

mul.nix

:

let
  mul = a: b: a * b;
in { inherit mul; }

fac.nix

:

let
  multMod = import ./mul.nix;
  fac = n:
    if n == 0
    then 1
    else multMod.mul n (fac (n - 1));
in { inherit fac; }

— , , ? Nix with

, , .

fac.nix

with

:

with import ./mul.nix;
let
  fac = n:
    if n == 0
    then 1
    else mul n (fac (n - 1));
in { inherit fac; }

— Nix.

, , , Derivation

. Derivation

— , - . C, "Hello World!", derivation :

Derive([("out","/nix/store/1nq46fyv3629slgxnagqn2c01skp7xrq-hello-world","","")],[("/nix/store/60xqp516mkfhf31n6ycyvxppcknb2dwr-build-hello.drv",["out"])],["/nix/store/wiviq2xyz0ylhl0qcgfgl9221nkvvxfj-hello.c"],"x86_64-linux","/nix/store/r5lh8zg768swlm9hxxfrf9j8gwyadi72-build-hello",[],[("builder","/nix/store/r5lh8zg768swlm9hxxfrf9j8gwyadi72-build-hello"),("name","hello-world"),("out","/nix/store/1nq46fyv3629slgxnagqn2c01skp7xrq-hello-world"),("src","/nix/store/wiviq2xyz0ylhl0qcgfgl9221nkvvxfj-hello.c"),("system","x86_64-linux")])

, , , , , : . , /nix/store

. , Nix , (sandbox). .

, ! , Nix derivation

, .

simple-derivation/default.nix

:

{ pkgs ? import <nixpkgs> {} }:

derivation {
  name = "hello-world";
  builder = pkgs.writeShellScript "build-hello" ''
    ${pkgs.coreutils}/bin/mkdir -p $out/bin
    ${pkgs.gcc}/bin/gcc $src -o $out/bin/hello -O2
  '';
  src = ./hello.c;
  system = builtins.currentSystem;
}

. , — , pkgs

. , : import <nixpkgs> {}

.

derivation

— , : name

— , builder

— , src

— , system

— , .

writeShellScript

— nixpkgs

, . Nix .

nix build

, .

$ nix build -f ./simple-derivation/default.nix
[1 built]

$ ./result/bin/hello 
Hello World!

nix build

, result

, /nix/store

.

$ ls -l result 
lrwxrwxrwx 1 user users 50 Mar 29 17:53 result -> /nix/store/vpcddray35g2jrv40dg1809xrmz73awi-simple

$ find /nix/store/vpcddray35g2jrv40dg1809xrmz73awi-simple
/nix/store/vpcddray35g2jrv40dg1809xrmz73awi-simple
/nix/store/vpcddray35g2jrv40dg1809xrmz73awi-simple/bin
/nix/store/vpcddray35g2jrv40dg1809xrmz73awi-simple/bin/hello

,

derivation

— , Nix . , cowsay

.

{ lib, stdenv, fetchurl, perl }:

stdenv.mkDerivation rec {
  version = "3.03+dfsg2";
  pname = "cowsay";

  src = fetchurl {
    url = "http://http.debian.net/debian/pool/main/c/cowsay/cowsay_${version}.orig.tar.gz";
    sha256 = "0ghqnkp8njc3wyqx4mlg0qv0v0pc996x2nbyhqhz66bbgmf9d29v";
  };

  buildInputs = [ perl ];

  postBuild = ''
    substituteInPlace cowsay --replace "%BANGPERL%" "!${perl}/bin/perl" \
      --replace "%PREFIX%" "$out"
  '';

  installPhase = ''
    mkdir -p $out/{bin,man/man1,share/cows}
    install -m755 cowsay $out/bin/cowsay
    ln -s cowsay $out/bin/cowthink
    install -m644 cowsay.1 $out/man/man1/cowsay.1
    ln -s cowsay.1 $out/man/man1/cowthink.1
    install -m644 cows/* -t $out/share/cows/
  '';

  meta = with lib; {
    description = "A program which generates ASCII pictures of a cow with a message";
    homepage = "https://en.wikipedia.org/wiki/Cowsay";
    license = licenses.gpl1;
    platforms = platforms.all;
    maintainers = [ maintainers.rob ];
  };
}

stdenv

— derivation

, : , . — setup

, builder

.

 $ nix build nixpkgs.stdenv

 $ find result/
result/
result/setup
result/nix-support

$ wc -l result/setup 
1330 result/setup

mkDerivation

— , derivation

.

, Arch Linux Gentoo, . , , (buildInputs

) .

Nix . , Nix Typeable, . Stay tuned!

, Nix Nix pills.

Nix: O que é e com o que devo usá-lo?

?

Nix

,

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