How to build Nix packages from source?

问题

I think NixOS is great, but can't figure out how to build a package from source. Understanding the Nix expression language is not the problem, but to know what to put in a default.nix in order to build a package.

Take for example the Nix expression for gedit:

{ stdenv, intltool, fetchurl, enchant, isocodes
, pkgconfig, gtk3, glib
, bash, wrapGAppsHook, itstool, libsoup, libxml2
, gnome3, librsvg, gdk_pixbuf, file, gspell }:

stdenv.mkDerivation rec {
  inherit (import ./src.nix fetchurl) name src;

  propagatedUserEnvPkgs = [ gnome3.gnome_themes_standard ];

  nativeBuildInputs = [ pkgconfig wrapGAppsHook ];

  buildInputs = [ gtk3 glib intltool itstool enchant isocodes
                  gdk_pixbuf gnome3.defaultIconTheme librsvg libsoup
                  gnome3.libpeas gnome3.gtksourceview libxml2
                  gnome3.gsettings_desktop_schemas gnome3.dconf file gspell ];

  enableParallelBuilding = true;

  preFixup = ''
    gappsWrapperArgs+=(--prefix LD_LIBRARY_PATH : "${stdenv.lib.makeLibraryPath [ gnome3.libpeas gnome3.gtksourceview ]}")
  '';

  meta = with stdenv.lib; {
    homepage = https://wiki.gnome.org/Apps/Gedit;
    description = "Official text editor of the GNOME desktop environment";
    maintainers = gnome3.maintainers;
    license = licenses.gpl2;
    platforms = platforms.linux;
  };
}

How can someone arrive to this solution? I must be missing something.

回答1:

It is no surprise that such a package definition is a bit overwhelming to anyone. When you understand what the effect of various attributes, your example package becomes quite straight-forward.

In my experience, you arrive at such a package definition as follows. I'll assume you're not packaging something from a language-specific repository for now. Something you might build with make, for example.

Start with mkDerivation
Watch the build fail
Fix an error, by adding dependencies, extra commands, configure flags, patches, etc.
Repeat

So there you have it, it's trial and error. Experience with the required build tools helps a lot.

Some hints:

Look at similar packages, how they are defined
Read the Nixpkgs documentation
Scan through the support code for language ecosystem packages
https://nixos.wiki/wiki/Generic_Algorithm_on_Doing_Packaging

来源：https://stackoverflow.com/questions/49209643/how-to-build-nix-packages-from-source

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