From 0536d0de90f7b56f914052cd86e42e2b105b79a8 Mon Sep 17 00:00:00 2001 From: benneti Date: Thu, 2 Sep 2021 11:37:21 +0200 Subject: [PATCH] update pkgs documentation --- doc/outputs/pkgs.md | 79 ++++++++++++++++++++++++++++++++++++++------- 1 file changed, 67 insertions(+), 12 deletions(-) diff --git a/doc/outputs/pkgs.md b/doc/outputs/pkgs.md index 548667f..4de93a8 100644 --- a/doc/outputs/pkgs.md +++ b/doc/outputs/pkgs.md @@ -13,18 +13,45 @@ the supported systems listed in the package's `meta.platforms` attribute. And, as usual, every package in the overlay is also available to any NixOS [host](../concepts/hosts.md). +Another convenient difference is that it is possible to use +[nvfetcher](https://github.com/berberman/nvfetcher) to keep packages up to +date. +This is best understood by the simple example below. + ## Example +It is possible to specify sources separately to keep them up to date semi +automatically. +The basic rules are specified in pkgs/sources.toml: +```toml +# nvfetcher.toml +[libinih] +src.github = "benhoyt/inih" +fetch.github = "benhoyt/inih" +``` +After changes to this file as well as to update the packages specified in there run +nvfetcher (for more details see [nvfetcher](https://github.com/berberman/nvfetcher)). + +The pkgs overlay is managed in +pkgs/default.nix: +```nix +final: prev: { + # keep sources first, this makes sources available to the pkgs + sources = prev.callPackage (import ./_sources/generated.nix) { }; + + # then, call packages with `final.callPackage` + libinih = prev.callPackage ./development/libraries/libinih { }; +} +``` + +Lastly the example package is in pkgs/development/libraries/libinih/default.nix: ```nix -{ stdenv, meson, ninja, lib, srcs, ... }: -let inherit (srcs) libinih; in +{ stdenv, meson, ninja, lib, sources, ... }: stdenv.mkDerivation { pname = "libinih"; - # version will resolve to 53, as specified in the final example below - inherit (libinih) version; - - src = libinih; + # version will resolve to the latest available on gitub + inherit (sources.libinih) version src; buildInputs = [ meson ninja ]; @@ -32,12 +59,14 @@ stdenv.mkDerivation { } ``` -pkgs/default.nix: -```nix -final: prev: { - libinih = prev.callPackage ./development/libraries/libinih { }; -} -``` + +## Migration from flake based approach +Previous to nvfetcher it was possible to manage sources via a pkgs/flake.nix, the main changes from there are that sources where in the attribute "srcs" (now "sources") and the contents of the sources where slightly different. +In order to switch to the new system, rewrite pkgs/flake.nix to a pkgs/sources.toml file using the documentation of nvfetcher, +add the line that calls the sources at the beginning of pkgs/default.nix, and +accomodate the small changes in the packages as can be seen from the example. + +The example package looked like: pkgs/flake.nix: ```nix @@ -51,4 +80,30 @@ pkgs/flake.nix: } ``` +pkgs/default.nix: +```nix +final: prev: { + # then, call packages with `final.callPackage` + libinih = prev.callPackage ./development/libraries/libinih { }; +} +``` + +pkgs/development/libraries/libinih/default.nix: +```nix +{ stdenv, meson, ninja, lib, srcs, ... }: +let inherit (srcs) libinih; in +stdenv.mkDerivation { + pname = "libinih"; + + # version will resolve to 53, as specified in the flake.nix file + inherit (libinih) version; + + src = libinih; + + buildInputs = [ meson ninja ]; + + # ... +} +``` + [pkgs]: https://github.com/NixOS/nixpkgs/tree/master/pkgs