Modular, context-aware and aspect-oriented dendritic Nix configurations.
Discussions: https://oeiuwq.zulipchat.com/join/nqp26cd4kngon6mo3ncgnuap/
den.oeiuwq.com
configurations
den
dendritic
nix
aspect
oriented
more examples
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README.md
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README.md
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```
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```nix
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# custom user-defined Nix classes.
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# Custom Nix classes.
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# Example: A class for role-based configuration between users and hosts
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roleClass =
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{ host, user }:
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{ class, aspect-chain }:
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den._.forward {
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each = lib.intersectLists (host.roles or []) (user.roles or []);
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fromClass = lib.id;
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intoClass = _: host.class;
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intoPath = _: [ ];
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fromAspect = _: lib.head aspect-chain;
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};
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den.ctx.user.includes = [ roleClass ];
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den.hosts.x86_64-linux.igloo = {
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roles = [ "devops" "gaming" ];
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users = {
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alice.roles = [ "gaming" ];
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bob.roles = [ "devops" ];
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};
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};
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den.aspects.alice = {
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# enabled when host supports gaming role
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gaming = { pkgs, ... }: { programs.steam.enable = true; };
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# enabled when host supports devops role
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devops = { pkgs, ... }: { virtualisation.podman.enable = true; };
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};
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```
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```nix
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# Forward guards allow feature-detection without mkIf/mkMerge cluttering.
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# any aspect can use my `persys` class to forward configs into
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# nixos.environment.persistance."/nix/persist/system"
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# **ONLY** when environment.persistance option is present at host.
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# Aspects use the `persys` class without any conditional. And guard guarantees
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# settings are applied **only** when impermanence module has been imported.
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persys = { host }: den._.forward {
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each = lib.singleton true;
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fromClass = _: "persys";
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intoClass = _: host.class;
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intoPath = _: [ "environment" "persistance" "/nix/persist/system" ];
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fromAspect = _: den.aspects.${host.aspect};
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guard = { options, ... }: options ? environment.persistance;
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guard = { options, config, ... }: options ? environment.persistance;
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};
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# enable on all hosts
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den.ctx.host.includes = [ persys ];
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# becomes nixos.environment.persistance."/nix/persist/system".hideMounts = true;
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# no mkIf, set configs and guard ensures to include only when Impermanence exists
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# aspects just attach config to custom class
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den.aspects.my-laptop.persys.hideMounts = true;
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```
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docs/src/content/docs/guides/custom-classes.mdx
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docs/src/content/docs/guides/custom-classes.mdx
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};
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```
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#### Example: Role based configuration between users and hosts
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A dynamic class for matching roles between users and hosts.
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```nix
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roleClass =
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{ host, user }:
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{ class, aspect-chain }:
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den._.forward {
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each = lib.intersectLists (host.roles or []) (user.roles or []);
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fromClass = lib.id;
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intoClass = _: host.class;
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intoPath = _: [ ];
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fromAspect = _: lib.head aspect-chain;
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};
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den.ctx.user.includes = [ roleClass ];
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den.hosts.x86_64-linux.igloo = {
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roles = [ "devops" "gaming" ];
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users = {
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alice.roles = [ "gaming" ];
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bob.roles = [ "devops" ];
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};
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};
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den.aspects.alice = {
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# enabled when host supports gaming role
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gaming = { pkgs, ... }: { programs.steam.enable = true; };
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# enabled when host supports devops role
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devops = { pkgs, ... }: { virtualisation.podman.enable = true; };
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};
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```
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#### Example: A git class that forwards to home-manager.
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```nix
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# enable class for all users:
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den.ctx.user.includes = [ nixClass ];
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# custom aspect that uses the `nix` class.
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nix-allowed = { user, ... }: { nix.allowed-users = [ user.userName ]; };
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templates/ci/modules/features/forward-from-custom-class.nix
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templates/ci/modules/features/forward-from-custom-class.nix
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}
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);
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test-pair-of-hosts = denTest (
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{
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den,
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lib,
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igloo,
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iceberg,
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...
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}:
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let
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forwarded =
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{ host, user }:
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{ class, aspect-chain }:
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den._.forward {
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each = lib.optional (lib.elem host.name [
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"igloo"
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"iceberg"
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]) user;
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fromClass = _: "iced";
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intoClass = _: host.class;
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intoPath = _: [ ];
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fromAspect = _: lib.head aspect-chain;
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};
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in
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{
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den.hosts.x86_64-linux.igloo.users.tux = { };
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den.hosts.x86_64-linux.iceberg.users.tux = { };
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den.aspects.igloo.homeManager.home.stateVersion = "25.11";
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den.ctx.default.includes = [ forwarded ];
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den.aspects.tux = {
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iced.networking.hostName = "iced";
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};
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expr = [
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igloo.networking.hostName
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iceberg.networking.hostName
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];
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expected = [
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"iced"
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"iced"
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];
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}
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);
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};
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}