nix-pkgset is a lightweight library that helps package nix derivations into cross-compilation aware package sets by splicing packages in the same fashion as nixpkgs.
WARNING: The library is still in proof of concept stage and the API is subject to change.
- Create package sets with splicing support (cross-compilation aware packages).
- Access non-spliced packages through
pkgs<host><target>. - Access extra package set variants like
pkgsCross.<crossSystem>andpkgsLLVM. - Avoid re-instantiating nixpkgs (see: 1000 instances of nixpkgs).
- Merge package sets together while keeping all of the above.
- Optimize unnecessary re-splicing of packages.
- Optimize unnecessary re-evaluation on equivalent
pkgs<host><target>sets.
let
# Create a new package set that inherits the scope from `pkgs`.
pkgset = nix-pkgset.lib.makePackageSet pkgs (self: {
# Create package `foo` which depends on `hello` at build time and run time.
foo = self.callPackage ({ runCommand, hello, pkgsBuildBuild }:
runCommand "foo" { nativeBuildInputs = [ hello ]; } ''
# `nativeBuildInputs` packages are spliced to run on the build platform.
hello
# Packages can be referenced by `pkgs<host><target>`.
${pkgsBuildBuild.hello}/bin/hello
# Packages are spliced to run on the host platform.
mkdir -p $out/bin
ln -s ${hello}/bin/hello $out/bin/foo
''
) { };
# Create package `bar` which depends on `hello` and `foo` at build time and run time.
bar = self.callPackage ({ runCommand, hello, foo, pkgsBuildBuild }:
runCommand "bar" { nativeBuildInputs = [ hello foo ]; } ''
# `nativeBuildInputs` packages are spliced to run on the build platform.
hello
foo
# Packages can be referenced by `pkgs<host><target>`.
${pkgsBuildBuild.hello}/bin/hello
${pkgsBuildBuild.foo}/bin/foo
# Packages are spliced to run on the host platform.
mkdir -p $out/bin
ln -s ${hello}/bin/hello $out/bin/hello
ln -s ${foo}/bin/foo $out/bin/foo
''
) { };
});
in
{
# We can reference packages from the package set.
foo = pkgset.foo;
bar = pkgset.bar;
# We can't reference packages that are not in the package set.
# Package `hello` is only available in `callPackage` scope.
hello = pkgset.hello; # Error
# We can reference packages from the package set `pkgs<host><target>`.
buildbuild-foo = pkgset.pkgsBuildBuild.foo;
buildbuild-bar = pkgset.pkgsBuildBuild.bar;
# We can't reference packages that are not in the package set.
# Package `hello` is only available in `callPackage` scope.
buildbuild-hello = pkgset.pkgsBuildBuild.hello; # Error
# We can create a derivation based on the package set's scope.
baz = pkgset.callPackage ({ mkDerivation, hello, bar, foo }:
mkDerivation {
name = "baz";
# `nativeBuildInputs` are spliced to run on the build platform.
nativeBuildInputs = [ hello bar ];
# `buildInputs` are spliced to run on the host platform.
buildInputs = [ foo ];
# ...
}
) { };
}let
firstPkgset = nix-pkgset.lib.makePackageSet pkgs (self: {
foo = self.callPackage ({ hello }: hello) { };
});
secondPkgset = nix-pkgset.lib.makePackageSet pkgs (self: {
bar = self.callPackage ({ hello }: hello) { };
});
mergedPkgset = nix-pkgset.lib.mergePackageSets [ firstPkgset secondPkgset ];
in
{
# We can reference packages from the package set.
foo = mergedPkgset.foo;
bar = mergedPkgset.bar;
# We can't reference packages that are not in the package set.
# Package `hello` is only available in `callPackage` scope.
hello = mergedPkgset.hello; # Error
# We can reference packages from the package set `pkgs<host><target>`.
buildbuild-foo = mergedPkgset.pkgsBuildBuild.foo;
buildbuild-bar = mergedPkgset.pkgsBuildBuild.bar;
# We can't reference packages that are not in the package set.
# Package `hello` is only available in `callPackage` scope.
buildbuild-hello = mergedPkgset.pkgsBuildBuild.hello; # Error
# We can create a derivation based on the package set's scope.
baz = mergedPkgset.callPackage ({ mkDerivation, hello, bar, foo }:
mkDerivation {
name = "baz";
# `nativeBuildInputs` are spliced to run on the build platform.
nativeBuildInputs = [ hello bar ];
# `buildInputs` are spliced to run on the host platform.
buildInputs = [ foo ];
# ...
}
) { };
}let
myPkgset = nix-pkgset.lib.makePackageSet pkgs (self: {
foo = self.callPackage ({ hello }: hello) { };
});
# Merge `pkgs` (from nixpkgs) with `myPkgset`.
mergedPkgset = nix-pkgset.lib.mergePackageSets [ pkgs myPkgset ];
in
{
# We can reference packages from the package set.
foo = mergedPkgset.foo; # From `myPkgset`
hello = mergedPkgset.hello; # From `pkgs`
# We can reference packages from the package set `pkgs<host><target>`.
buildbuild-foo = mergedPkgset.pkgsBuildBuild.foo; # From `myPkgset`
buildbuild-hello = mergedPkgset.pkgsBuildBuild.hello; # From `pkgs`
}let
# Create a package set from an overlay instead on instantiating a new nixpkgs instance.
rustOverlay = nix-pkgset.lib.packageSetFromOverlay pkgs (import rust-overlay);
in
{
rust-stable = rustOverlay.rust-bin.stable.latest.minimal;
}{
inputs = {
nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
nix-pkgset.url = "github:szlend/nix-pkgset";
nix-pkgset.inputs.nixpkgs.follows = "nixpkgs";
};
outputs = { self, nixpkgs, nix-pkgset, ... }:
let
lib = nixpkgs.lib;
forAllSystems = lib.genAttrs lib.systems.flakeExposed;
makePackageSetFor = pkgs: nix-pkgset.lib.makePackageSet pkgs (self: {
foo = self.callPackage ({ hello }: hello) { }; # Just re-export `hello` as `foo`
});
in
{
# legacyPackages.<system>.foo
# legacyPackages.<system>.pkgsBuildBuild.foo
# legacyPackages.<system>.pkgsCross.aarch64-multiplatform.foo
# legacyPackages.<system>.pkgsCross.aarch64-multiplatform.pkgsBuildBuild.foo
legacyPackages = forAllSystems (system:
makePackageSetFor nixpkgs.legacyPackages.${system}
);
# packages.<system>.foo
packages = forAllSystems (system:
lib.filterAttrs (_: lib.isDerivation) self.legacyPackages.${system}
);
};
}{
inputs = {
nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
nix-pkgset.url = "github:szlend/nix-pkgset";
nix-pkgset.inputs.nixpkgs.follows = "nixpkgs";
foo-pkgset.url = "/my/foo-pkgset";
foo-pkgset.inputs.nix-pkgset.follows = "nix-pkgset";
foo-pkgset.inputs.nixpkgs.follows = "nixpkgs";
};
outputs = { self, nixpkgs, nix-pkgset, foo-pkgset, ... }:
let
lib = nixpkgs.lib;
forAllSystems = lib.genAttrs lib.systems.flakeExposed;
makePackageSetForSystem = system:
let
# Contains the entire nixpkgs package set.
pkgs = nixpkgs.legacyPackages.${system};
# Contains `foo` from `foo-pkgset`.
fooPkgset = foo-pkgset.legacyPackages.${system};
# Contains `bar`
barPkgset = nix-pkgset.lib.makePackageSet pkgs (self: {
bar = self.callPackage ({ hello }: hello) { }; # Just re-export `hello` as `bar`
});
# Merge all package sets
in nix-pkgset.lib.mergePackageSets [ pkgs fooPkgset barPkgset ];
in
{
devShells = forAllSystems (system:
let
# Create a merged package set for this system.
pkgs = makePackageSetForSystem system;
in
{
# A non-spliced devShell (doesn't care about cross-compilation).
default = pkgs.mkShell {
packages = [ pkgs.hello pkgs.foo pkgs.bar ];
};
# A spliced devShell (packages are set up for cross-compilation).
spliced = pkgs.pkgsCross.aarch64-multiplatform.callPackage ({ mkShell, hello, foo, bar }:
mkShell {
nativeBuildInputs = [ hello foo ];
buildInputs = [ bar ];
}
) { };
}
);
};
}