groups

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.

👉 Browse Options