groups

state:	internal
maintainers:	@DavHau

Introduction

Module to deal with package sets (so called groups in dream2nix)

Separate different kinds of dependencies

Many language specific package managers support declaration of different kinds of dependencies like, for example: - dependencies, devDependencies in nodejs - dependencies, optional-dependencies.dev, optional-dependencies.test, etc. in python

The dream2nix groups module allows to keep the upstream separation by splitting the dependency definitions into different attribute sets located at:

config.groups.<group>.packages.<name>.<version>

This separation is relevant because not all dependencies are needed for all targets. A devShell for example requires the dev dependencies, while the runtime environment of the built package does not.

Re-use package definitions

Each package definition in a group contains two important attributes: - [...].packages.<name>.<version>.module: for the package definition - [...].packages.<name>.<version>.public: for the final evaluated derivation

Having the package definition (module) separated from the result allows to re-use the definition elsewhere. For example, a new group could be assembled by referring to the modules of existing groups:

{config, dream2nix, ...}: {

  # TODO: This is too complex. Defining a selector function should be enough to
  #   assemble new groups.
  # Any specifics about a package other than it's `ecosystem`, `name, `version
  #   are not important, as everything else is expressed via override modules.
  # Simply naming the keys of packages should be sufficient to assemble groups.

  # The dev group
  groups.dev = {

    # a hello package
    packages.hello."1.0.0".module = {
      imports = [
        dream2nix.modules.dream2nix.mkDerivation
      ];
      name = "hello";
      version = "1.0.0";
      mkDerivation.buildPhase = lib.mkForce ''echo "Hello World!" > $out''
    };

    # a modified hello package depending on the original hello definition
    packages.hello-mod."1.0.0".module = {
      imports = [
        # import the module definition of `hello` from above
        config.groups.dev.packages.hello.module
      ];
      mkDerivation.buildPhase = ''echo "Good Bye World!" > $out'';
    };
  };

  # The test group
  groups.test = {

    # a hello package based on `hello`` from the `dev` group
    packages.hello."1.0.0".module = {
      imports = [
        # import the module definition of `hello` from the `dev` group
        config.groups.dev.packages.hello.module
      ];
      mkDerivation.buildPhase = ''echo "Happy testing!" > $out''
    };
  }
}

TODOs

• Expose all package candidates somehow (not grouped)
• Create groups by simply defining selector functions instead of referring to other group's packages modules.

Options

groups

Holds multiple package sets (eg. groups). Holds shared config (overrideAll) and overrides on a global and on a per group basis.

type	lazy attribute set of (submodule)
source	dream2nix/modules/dream2nix/WIP-groups/interface.nix

groups.<name>.overrideAll

Common configuration for all packages in all groups

type	module
source	dream2nix/modules/dream2nix/WIP-groups/interface.nix
default	{ }

groups.<name>.overrides

Holds overrides for the packages in the current groups

type	lazy attribute set of module
source	dream2nix/modules/dream2nix/WIP-groups/interface.nix
default	{ }

groups.<name>.packages

Contains all packages for the current group in the forma of a set like:

{
  package1."1.0.0" = {
    module = {
      # the package configuration
    };
    public = {
      # the evaluated package
    };
  };
  package2."1.0.0" = {
    module = {
      # the package configuration
    };
    public = {
      # the evaluated package
    };
  };
}

type	lazy attribute set of lazy attribute set of (submodule)
source	dream2nix/modules/dream2nix/WIP-groups/interface.nix

groups.<name>.packages.<name>.<name>.module

The package configuration

type	module
source	dream2nix/modules/dream2nix/WIP-groups/interface.nix
default	{ }

groups.<name>.packages.<name>.<name>.public

The evaluated package ready to consume

type	package (read only)
source	dream2nix/modules/dream2nix/WIP-groups/interface.nix
default	config.evaluated.public

overrideAll

Overrides applied on all dependencies.

type	module
source	dream2nix/modules/dream2nix/overrides/interface.nix
default	{ }
example	{ mkDerivation = { doCheck = false; }; }

overrides

Overrides applied only on dependencies matching the specified name.

type	attribute set of module
source	dream2nix/modules/dream2nix/overrides/interface.nix
default	{ }
example	{ hello = { mkDerivation = { postPatch = '' substituteInPlace Makefile --replace /usr/local /usr ''; }; }; }