Merge pull request 'feat: custom evaluation' (#1) from custom-activation into main

Reviewed-on: DGNum/colmena#1

.editorconfig

@@ -10,8 +10,7 @@ insert_final_newline = true
 trim_trailing_whitespace = true
 charset = utf-8
 
-# Rust
+[*.json]
-[*.rs]
 indent_style = space
 indent_size = 2
 

.github/workflows/build.yml

@@ -13,19 +13,23 @@ jobs:
             image: ubuntu-latest
             system: aarch64-linux
           - label: x86_64-darwin
-            image: macos-12
+            image: macos-latest
+            system: x86_64-darwin
+          - label: aarch64-darwin
+            image: macos-latest
+            system: aarch64-darwin
 
     name: ${{ matrix.label }}
     runs-on: ${{ matrix.image }}
     steps:
-      - uses: actions/checkout@v3.3.0
+      - uses: actions/checkout@v4.2.2
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@9b252454a8d70586c4ee7f163bf4bb1e9de3d763 # v2
+        uses: DeterminateSystems/nix-installer-action@b92f66560d6f97d6576405a7bae901ab57e72b6a # v15
 
       - name: Set up QEMU
-        uses: docker/setup-qemu-action@v2.1.0
+        uses: docker/setup-qemu-action@v3.2.0
-        if: matrix.system != ''
+        if: matrix.system == 'aarch64-linux'
 
       - name: Generate System Flags
         run: |
@@ -39,7 +43,7 @@ jobs:
           HOST_SYSTEM: '${{ matrix.system }}'
 
       - name: Enable Binary Cache
-        uses: cachix/cachix-action@v12
+        uses: cachix/cachix-action@v15
         with:
           name: colmena
           authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
@@ -49,3 +53,60 @@ jobs:
 
       - name: Build manual
         run: nix build .#manual -L
+
+  nix-matrix:
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.set-matrix.outputs.matrix }}
+    steps:
+      - uses: actions/checkout@v4.2.2
+
+      - uses: DeterminateSystems/nix-installer-action@v15
+        continue-on-error: true # Self-hosted runners already have Nix installed
+
+      - name: Enable Binary Cache
+        uses: cachix/cachix-action@v15
+        with:
+          name: colmena
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+
+      - id: set-matrix
+        name: Generate Nix Matrix
+        run: |
+          set -Eeu
+          matrix="$(nix eval --json '.#githubActions.matrix')"
+          echo "matrix=$matrix" >> "$GITHUB_OUTPUT"
+
+  nix-matrix-job:
+    name: ${{ matrix.name }}
+    runs-on: ${{ matrix.os }}
+    needs:
+      - build
+      - nix-matrix
+    strategy:
+      matrix: ${{ fromJSON(needs.nix-matrix.outputs.matrix) }}
+    steps:
+      - name: Maximize build space
+        uses: easimon/maximize-build-space@master
+        with:
+          remove-dotnet: 'true'
+          build-mount-path: /nix
+
+      - name: Set /nix permissions
+        run: |
+          sudo chown root:root /nix
+
+      - uses: actions/checkout@v4.2.2
+
+      - uses: DeterminateSystems/nix-installer-action@v15
+        continue-on-error: true # Self-hosted runners already have Nix installed
+
+      - name: Enable Binary Cache
+        uses: cachix/cachix-action@v15
+        with:
+          name: colmena
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+
+      - name: Build ${{ matrix.attr }}
+        run: |
+          nix build --no-link --print-out-paths -L '.#${{ matrix.attr }}'

.github/workflows/linters.yml

@@ -10,13 +10,13 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3.3.0
+      - uses: actions/checkout@v4.2.2
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@9b252454a8d70586c4ee7f163bf4bb1e9de3d763 # v2
+        uses: DeterminateSystems/nix-installer-action@b92f66560d6f97d6576405a7bae901ab57e72b6a # v15
 
       - name: Enable binary cache
-        uses: cachix/cachix-action@v12
+        uses: cachix/cachix-action@v15
         with:
           name: colmena
           authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'

.github/workflows/manual-stable.yml

@@ -16,13 +16,13 @@ jobs:
     if: github.repository == 'zhaofengli/colmena'
 
     steps:
-      - uses: actions/checkout@v3.3.0
+      - uses: actions/checkout@v4.2.2
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@9b252454a8d70586c4ee7f163bf4bb1e9de3d763 # v2
+        uses: DeterminateSystems/nix-installer-action@b92f66560d6f97d6576405a7bae901ab57e72b6a # v15
 
       - name: Enable Binary Cache
-        uses: cachix/cachix-action@v12
+        uses: cachix/cachix-action@v15
         with:
           name: colmena
           authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
@@ -38,7 +38,7 @@ jobs:
         run: nix build .#manual -L
 
       - name: Deploy manual
-        uses: JamesIves/github-pages-deploy-action@4.1.6
+        uses: JamesIves/github-pages-deploy-action@v4.6.9
         with:
           branch: gh-pages
           folder: result
@@ -52,7 +52,7 @@ jobs:
         if: ${{ env.api_version == env.latest_stable_api }}
 
       - name: Deploy redirect farm
-        uses: JamesIves/github-pages-deploy-action@4.1.6
+        uses: JamesIves/github-pages-deploy-action@v4.6.9
         with:
           branch: gh-pages
           folder: result-redirectFarm

.github/workflows/manual.yml

@@ -16,13 +16,13 @@ jobs:
     if: github.repository == 'zhaofengli/colmena'
 
     steps:
-      - uses: actions/checkout@v3.3.0
+      - uses: actions/checkout@v4.2.2
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@9b252454a8d70586c4ee7f163bf4bb1e9de3d763 # v2
+        uses: DeterminateSystems/nix-installer-action@b92f66560d6f97d6576405a7bae901ab57e72b6a # v15
 
       - name: Enable Binary Cache
-        uses: cachix/cachix-action@v12
+        uses: cachix/cachix-action@v15
         with:
           name: colmena
           authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
@@ -32,7 +32,7 @@ jobs:
         run: nix build .#manual -L
 
       - name: Deploy manual
-        uses: JamesIves/github-pages-deploy-action@v4.3.4
+        uses: JamesIves/github-pages-deploy-action@v4.6.9
         with:
           branch: gh-pages
           folder: result
@@ -47,7 +47,7 @@ jobs:
         run: nix build .#manual.redirectFarm -L
 
       - name: Deploy redirect farm
-        uses: JamesIves/github-pages-deploy-action@4.1.6
+        uses: JamesIves/github-pages-deploy-action@v4.6.9
         with:
           branch: gh-pages
           folder: result-redirectFarm

.github/workflows/tests.yml

@@ -13,15 +13,15 @@ jobs:
     name: ${{ matrix.os.label }}
     runs-on: ${{ matrix.os.image }}
     steps:
-      - uses: actions/checkout@v3.3.0
+      - uses: actions/checkout@v4.2.2
         with:
           fetch-depth: 0
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@9b252454a8d70586c4ee7f163bf4bb1e9de3d763 # v2
+        uses: DeterminateSystems/nix-installer-action@b92f66560d6f97d6576405a7bae901ab57e72b6a # v15
 
       - name: Enable Binary Cache
-        uses: cachix/cachix-action@v12
+        uses: cachix/cachix-action@v15
         with:
           name: colmena
           authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'

.gitignore

@@ -1,3 +1,4 @@
 result*
 /target
 /.direnv
+/.vscode

.srcignore

@@ -0,0 +1,18 @@
+# Exclusions from source distribution
+#
+# Files listed here will not be part of colmena.src
+
+/.github
+/CNAME
+/renovate.json
+
+/manual
+/integration-tests
+
+/nix
+/default.nix
+/flake-compat.nix
+/package.nix
+/shell.nix
+
+# vim: set ft=gitignore:

Cargo.toml

@@ -9,18 +9,17 @@ edition = "2021"
 [dependencies]
 async-stream = "0.3.5"
 async-trait = "0.1.68"
-atty = "0.2"
 clap = { version = "4.3", features = ["derive"] }
 clap_complete = "4.3"
 clicolors-control = "1"
 console = "0.15.5"
 const_format = "0.2.30"
-env_logger = "0.10.0"
+env_logger = "0.11.0"
 futures = "0.3.28"
 glob = "0.3.1"
-hostname = "0.3.1"
+hostname = "0.4.0"
 indicatif = "0.17.3"
-itertools = "0.11.0"
+itertools = "0.13.0"
 libc = "0.2.144"
 log = "0.4.17"
 quit = "2.0.0"
@@ -28,12 +27,12 @@ regex = "1"
 serde = { version = "1.0.163", features = ["derive"] }
 serde_json = "1.0"
 shell-escape = "0.1.5"
-snafu = { version = "0.7.4", features = ["backtrace", "backtraces-impl-backtrace-crate"] }
+snafu = { version = "0.8.0", features = ["backtrace", "backtraces-impl-backtrace-crate"] }
 sys-info = "0.9.1"
 tempfile = "3.5.0"
 tokio-stream = "0.1.14"
 uuid = { version = "1.3.2", features = ["serde", "v4"] }
-validator = { version = "0.16.0", features = ["derive"] }
+validator = { version = "0.19.0", features = ["derive"] }
 
 [dev-dependencies]
 ntest = "0.9.0"

README.md

@@ -3,7 +3,7 @@
 [![Matrix Channel](https://img.shields.io/badge/Matrix-%23colmena%3Anixos.org-blueviolet)](https://matrix.to/#/#colmena:nixos.org)
 [![Stable Manual](https://img.shields.io/badge/Manual-Stable-informational)](https://colmena.cli.rs/stable)
 [![Unstable Manual](https://img.shields.io/badge/Manual-Unstable-orange)](https://colmena.cli.rs/unstable)
-[![Build](https://github.com/zhaofengli/colmena/workflows/Build/badge.svg)](https://github.com/zhaofengli/colmena/actions/workflows/build.yml)
+[![Build](https://github.com/zhaofengli/colmena/actions/workflows/build.yml/badge.svg)](https://github.com/zhaofengli/colmena/actions/workflows/build.yml)
 
 Colmena is a simple, stateless [NixOS](https://nixos.org) deployment tool modeled after [NixOps](https://github.com/NixOS/nixops) and [morph](https://github.com/DBCDK/morph), written in Rust.
 It's a thin wrapper over Nix commands like `nix-instantiate` and `nix-copy-closure`, and supports parallel deployment.

flake.lock

@@ -31,13 +31,33 @@
         "type": "github"
       }
     },
+    "nix-github-actions": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1729742964,
+        "narHash": "sha256-B4mzTcQ0FZHdpeWcpDYPERtyjJd/NIuaQ9+BV1h+MpA=",
+        "owner": "nix-community",
+        "repo": "nix-github-actions",
+        "rev": "e04df33f62cdcf93d73e9a04142464753a16db67",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "nix-github-actions",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1696019113,
+        "lastModified": 1730785428,
-        "narHash": "sha256-X3+DKYWJm93DRSdC5M6K5hLqzSya9BjibtBsuARoPco=",
+        "narHash": "sha256-Zwl8YgTVJTEum+L+0zVAWvXAGbWAuXHax3KzuejaDyo=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "f5892ddac112a1e9b3612c39af1b72987ee5783a",
+        "rev": "4aa36568d413aca0ea84a1684d2d46f55dbabad7",
         "type": "github"
       },
       "original": {
@@ -51,22 +71,23 @@
       "inputs": {
         "flake-compat": "flake-compat",
         "flake-utils": "flake-utils",
+        "nix-github-actions": "nix-github-actions",
         "nixpkgs": "nixpkgs",
         "stable": "stable"
       }
     },
     "stable": {
       "locked": {
-        "lastModified": 1696039360,
+        "lastModified": 1730883749,
-        "narHash": "sha256-g7nIUV4uq1TOVeVIDEZLb005suTWCUjSY0zYOlSBsyE=",
+        "narHash": "sha256-mwrFF0vElHJP8X3pFCByJR365Q2463ATp2qGIrDUdlE=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "32dcb45f66c0487e92db8303a798ebc548cadedc",
+        "rev": "dba414932936fde69f0606b4f1d87c5bc0003ede",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "nixos-23.05",
+        "ref": "nixos-24.05",
         "repo": "nixpkgs",
         "type": "github"
       }

flake.nix

@@ -3,7 +3,12 @@
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-    stable.url = "github:NixOS/nixpkgs/nixos-23.05";
+    stable.url = "github:NixOS/nixpkgs/nixos-24.05";
+
+    nix-github-actions = {
+      url = "github:nix-community/nix-github-actions";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
 
     flake-utils.url = "github:numtide/flake-utils";
 
@@ -13,12 +18,41 @@
     };
   };
 
-  outputs = { self, nixpkgs, stable, flake-utils, ... } @ inputs: let
+  outputs = {
+    self,
+    nixpkgs,
+    stable,
+    flake-utils,
+    nix-github-actions,
+    ...
+  } @ inputs: let
     supportedSystems = [ "x86_64-linux" "i686-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
     colmenaOptions = import ./src/nix/hive/options.nix;
     colmenaModules = import ./src/nix/hive/modules.nix;
+
+    # Temporary fork of nix-eval-jobs with changes to be upstreamed
+    # Mostly for the integration test setup and not needed in most use cases
+    _evalJobsOverlay = final: prev: let
+      patched = prev.nix-eval-jobs.overrideAttrs (old: {
+        version = old.version + "-colmena";
+        patches = (old.patches or []) ++ [
+          # Allows NIX_PATH to be honored
+          (final.fetchpatch {
+            url = "https://github.com/zhaofengli/nix-eval-jobs/commit/6ff5972724230ac2b96eb1ec355cd25ca512ef57.patch";
+            hash = "sha256-2NiMYpw27N+X7Ixh2HkP3fcWvopDJWQDVjgRdhOL2QQ";
+          })
+        ];
+      });
+    in {
+      nix-eval-jobs = patched;
+    };
   in flake-utils.lib.eachSystem supportedSystems (system: let
-    pkgs = nixpkgs.legacyPackages.${system};
+    pkgs = import nixpkgs {
+      inherit system;
+      overlays = [
+        _evalJobsOverlay
+      ];
+    };
   in rec {
     # We still maintain the expression in a Nixpkgs-acceptable form
     defaultPackage = self.packages.${system}.colmena;
@@ -83,11 +117,21 @@
     in if pkgs.stdenv.isLinux then import ./integration-tests {
       pkgs = import nixpkgs {
         inherit system;
-        overlays = [ self.overlays.default inputsOverlay ];
+        overlays = [
+          self.overlays.default
+          inputsOverlay
+
+          _evalJobsOverlay
+        ];
       };
       pkgsStable = import stable {
         inherit system;
-        overlays = [ self.overlays.default inputsOverlay ];
+        overlays = [
+          self.overlays.default
+          inputsOverlay
+
+          _evalJobsOverlay
+        ];
       };
     } else {};
   }) // {
@@ -104,6 +148,12 @@
       inherit rawHive colmenaOptions colmenaModules;
       hermetic = true;
     };
+
+    githubActions = nix-github-actions.lib.mkGithubMatrix {
+      checks = {
+        inherit (self.checks) x86_64-linux;
+      };
+    };
   };
 
   nixConfig = {

garnix.yaml

@@ -1,3 +0,0 @@
-builds:
-  include:
-    - 'checks.x86_64-linux.*'

integration-tests/default.nix

@@ -8,8 +8,18 @@
   apply-local = import ./apply-local { inherit pkgs; };
   build-on-target = import ./build-on-target { inherit pkgs; };
   exec = import ./exec { inherit pkgs; };
-  flakes = import ./flakes { inherit pkgs; };
+
-  flakes-streaming = import ./flakes { inherit pkgs; evaluator = "streaming"; };
+  # FIXME: The old evaluation method doesn't work purely with Nix 2.21+
+  flakes = import ./flakes {
+    inherit pkgs;
+    extraApplyFlags = "--experimental-flake-eval";
+  };
+  flakes-impure = import ./flakes {
+    inherit pkgs;
+    pure = false;
+  };
+  #flakes-streaming = import ./flakes { inherit pkgs; evaluator = "streaming"; };
+
   parallel = import ./parallel { inherit pkgs; };
 
   allow-apply-all = import ./allow-apply-all { inherit pkgs; };

integration-tests/flakes/default.nix

@@ -1,13 +1,29 @@
 { pkgs
 , evaluator ? "chunked"
+, extraApplyFlags ? ""
+, pure ? true
 }:
 
 let
+  inherit (pkgs) lib;
+
   tools = pkgs.callPackage ../tools.nix {
     targets = [ "alpha" ];
   };
+
+  applyFlags = "--evaluator ${evaluator} ${extraApplyFlags}"
+    + lib.optionalString (!pure) "--impure";
+
+  # From integration-tests/nixpkgs.nix
+  colmenaFlakeInputs = pkgs._inputs;
 in tools.runTest {
-  name = "colmena-flakes-${evaluator}";
+  name = "colmena-flakes-${evaluator}"
+    + lib.optionalString (!pure) "-impure";
+
+  nodes.deployer = {
+    virtualisation.additionalPaths =
+      lib.mapAttrsToList (k: v: v.outPath) colmenaFlakeInputs;
+  };
 
   colmena.test = {
     bundle = ./.;
@@ -16,12 +32,13 @@ in tools.runTest {
       import re
 
       deployer.succeed("sed -i 's @nixpkgs@ path:${pkgs._inputs.nixpkgs.outPath}?narHash=${pkgs._inputs.nixpkgs.narHash} g' /tmp/bundle/flake.nix")
+      deployer.succeed("sed -i 's @colmena@ path:${tools.colmena.src} g' /tmp/bundle/flake.nix")
 
       with subtest("Lock flake dependencies"):
           deployer.succeed("cd /tmp/bundle && nix --extra-experimental-features \"nix-command flakes\" flake lock")
 
       with subtest("Deploy with a plain flake without git"):
-          deployer.succeed("cd /tmp/bundle && ${tools.colmenaExec} apply --on @target --evaluator ${evaluator}")
+          deployer.succeed("cd /tmp/bundle && ${tools.colmenaExec} apply --on @target ${applyFlags}")
           alpha.succeed("grep FIRST /etc/deployment")
 
       with subtest("Deploy with a git flake"):
@@ -29,21 +46,22 @@ in tools.runTest {
 
           # don't put probe.nix in source control - should fail
           deployer.succeed("cd /tmp/bundle && git init && git add flake.nix flake.lock hive.nix tools.nix")
-          logs = deployer.fail("cd /tmp/bundle && run-copy-stderr ${tools.colmenaExec} apply --on @target --evaluator ${evaluator}")
+          logs = deployer.fail("cd /tmp/bundle && run-copy-stderr ${tools.colmenaExec} apply --on @target ${applyFlags}")
-          assert re.search(r"probe.nix.*No such file or directory", logs)
+          assert re.search(r"probe.nix.*(No such file or directory|does not exist)", logs), "Expected error message not found in log"
 
           # now it should succeed
           deployer.succeed("cd /tmp/bundle && git add probe.nix")
-          deployer.succeed("cd /tmp/bundle && ${tools.colmenaExec} apply --on @target --evaluator ${evaluator}")
+          deployer.succeed("cd /tmp/bundle && ${tools.colmenaExec} apply --on @target ${applyFlags}")
           alpha.succeed("grep SECOND /etc/deployment")
 
+    '' + lib.optionalString pure ''
       with subtest("Check that impure expressions are forbidden"):
           deployer.succeed("sed -i 's|SECOND|''${builtins.readFile /etc/hostname}|g' /tmp/bundle/probe.nix")
-          logs = deployer.fail("cd /tmp/bundle && run-copy-stderr ${tools.colmenaExec} apply --on @target --evaluator ${evaluator}")
+          logs = deployer.fail("cd /tmp/bundle && run-copy-stderr ${tools.colmenaExec} apply --on @target ${applyFlags}")
-          assert re.search(r"access to absolute path.*forbidden in pure eval mode", logs)
+          assert re.search(r"access to absolute path.*forbidden in pure (eval|evaluation) mode", logs), "Expected error message not found in log"
 
       with subtest("Check that impure expressions can be allowed with --impure"):
-          deployer.succeed("cd /tmp/bundle && ${tools.colmenaExec} apply --on @target --evaluator ${evaluator} --impure")
+          deployer.succeed("cd /tmp/bundle && ${tools.colmenaExec} apply --on @target ${applyFlags} --impure")
           alpha.succeed("grep deployer /etc/deployment")
     '';
   };

integration-tests/flakes/flake.nix

@@ -3,13 +3,15 @@
 
   inputs = {
     nixpkgs.url = "@nixpkgs@";
+    colmena.url = "@colmena@";
   };
 
-  outputs = { self, nixpkgs }: let
+  outputs = { self, nixpkgs, colmena }: let
     pkgs = import nixpkgs {
       system = "x86_64-linux";
     };
   in {
     colmena = import ./hive.nix { inherit pkgs; };
+    colmenaHive = colmena.lib.makeHive self.outputs.colmena;
   };
 }

integration-tests/tools.nix

@@ -140,7 +140,7 @@ let
     nix.settings.substituters = lib.mkForce [];
 
     virtualisation = {
-      memorySize = 4096;
+      memorySize = 6144;
       writableStore = true;
       additionalPaths = [
         "${pkgs.path}"
@@ -165,6 +165,9 @@ let
         exec "$@" 2> >(tee /dev/stderr)
       '')
     ];
+
+    # Re-enable switch-to-configuration
+    system.switch.enable = true;
   };
 
   # Setup for target nodes
@@ -180,6 +183,9 @@ let
       sshKeys.snakeOilPublicKey
     ];
     virtualisation.writableStore = true;
+
+    # Re-enable switch-to-configuration
+    system.switch.enable = true;
   };
 
   nodes = let

manual/src/tutorial/flakes.md

@@ -90,6 +90,34 @@ To build and deploy to all nodes:
 colmena apply
 ```
 
+## Direct Flake Evaluation (Experimental)
+
+By default, Colmena uses `nix-instantiate` to evaluate your flake which does not work purely on Nix 2.21+, necessitating the use of `--impure`.
+There is experimental support for evaluating flakes directly with `nix eval`, enabled via `--experimental-flake-eval`.
+
+To use this new evaluation mode, your flake needs to depend on Colmena itself as an input and expose a new output called `colmenaHive`:
+
+```diff
+ {
+   inputs = {
++    # ADDED: Colmena input
++    colmena.url = "github:zhaofengli/colmena";
+
+     # ... Rest of configuration ...
+   };
+   outputs = { self, colmena, ... }: {
++    # ADDED: New colmenaHive output
++    colmenaHive = colmena.lib.makeHive self.outputs.colmena;
+
+     # Your existing colmena output
+     colmena = {
+       # ... Rest of configuration ...
+     };
+   };
+ }
+```
+
+
 ## Next Steps
 
 - Head to the [Features](../features/index.md) section to see what else Colmena can do.

package.nix

@@ -1,13 +1,16 @@
-{ lib, stdenv, rustPlatform, installShellFiles, nix-eval-jobs }:
+{ lib
+, stdenv
+, rustPlatform
+, nix-gitignore
+, installShellFiles
+, nix-eval-jobs
+}:
 
 rustPlatform.buildRustPackage rec {
   pname = "colmena";
   version = "0.5.0-pre";
 
-  src = lib.cleanSourceWith {
+  src = nix-gitignore.gitignoreSource [ ./.srcignore ] ./.;
-    filter = name: type: !(type == "directory" && builtins.elem (baseNameOf name) [ "target" "manual" "integration-tests" ]);
-    src = lib.cleanSource ./.;
-  };
 
   cargoLock = {
     lockFile = ./Cargo.lock;

renovate.json

@@ -0,0 +1,14 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "config:recommended",
+    "group:allNonMajor"
+  ],
+  "lockFileMaintenance": {
+    "enabled": true,
+    "extends": ["schedule:weekly"]
+  },
+  "nix": {
+    "enabled": true
+  }
+}

src/cli.rs

@@ -10,7 +10,7 @@ use env_logger::fmt::WriteStyle;
 use crate::{
     command::{self, apply::DeployOpts},
     error::ColmenaResult,
-    nix::{Hive, HivePath},
+    nix::{hive::EvaluationMethod, Hive, HivePath},
 };
 
 /// Base URL of the manual, without the trailing slash.
@@ -137,6 +137,21 @@ This only works when building locally.
         value_names = ["NAME", "VALUE"],
     )]
     nix_option: Vec<String>,
+    #[arg(
+        long,
+        default_value_t,
+        help = "Use direct flake evaluation (experimental)",
+        long_help = r#"If enabled, flakes will be evaluated using `nix eval`. This requires the flake to depend on Colmena as an input and expose a compatible `colmenaHive` output:
+
+  outputs = { self, colmena, ... }: {
+    colmenaHive = colmena.lib.makeHive self.outputs.colmena;
+    colmena = ...;
+  };
+
+This is an experimental feature."#,
+        global = true
+    )]
+    experimental_flake_eval: bool,
     #[arg(
         long,
         value_name = "WHEN",
@@ -262,6 +277,11 @@ async fn get_hive(opts: &Opts) -> ColmenaResult<Hive> {
         hive.set_impure(true);
     }
 
+    if opts.experimental_flake_eval {
+        log::warn!("Using direct flake evaluation (experimental)");
+        hive.set_evaluation_method(EvaluationMethod::DirectFlakeEval);
+    }
+
     for chunks in opts.nix_option.chunks_exact(2) {
         let [name, value] = chunks else {
             unreachable!()

src/error.rs

@@ -64,6 +64,12 @@ pub enum ColmenaError {
     #[snafu(display("Don't know how to connect to the node"))]
     NoTargetHost,
 
+    #[snafu(display(
+        "Don't know how to deploy node: {} -- does your system type support deployment?",
+        node_name
+    ))]
+    UndeployableHost { node_name: String },
+
     #[snafu(display("Node name cannot be empty"))]
     EmptyNodeName,
 

src/job.rs

@@ -874,11 +874,17 @@ fn describe_node_list(nodes: &[NodeName]) -> Option<String> {
         }
 
         let (idx, next) = next.unwrap();
-        let remaining = rough_limit - s.len();
+        let remaining_text = rough_limit - s.len();
+        let remaining_nodes = total - idx;
 
-        if next.len() + other_text.len() >= remaining {
+        if next.len() + other_text.len() >= remaining_text {
-            write!(s, ", and {} other nodes", total - idx).unwrap();
+            if remaining_nodes == 1 {
-            break;
+                write!(s, ", and {}", next.as_str()).unwrap();
+                break;
+            } else {
+                write!(s, ", and {} other nodes", remaining_nodes).unwrap();
+                break;
+            }
         }
     }
 

src/nix/hive/assets.rs

@@ -51,7 +51,10 @@ impl Assets {
             // We explicitly specify `path:` instead of letting Nix resolve
             // automatically, which would involve checking parent directories
             // for a git repository.
-            let uri = format!("path:{}", temp_dir.path().to_str().unwrap());
+            let uri = format!(
+                "path:{}",
+                temp_dir.path().canonicalize().unwrap().to_str().unwrap()
+            );
             let _ = lock_flake_quiet(&uri).await;
             let assets_flake = Flake::from_uri(uri).await?;
             assets_flake_uri = Some(assets_flake.locked_uri().to_owned());

src/nix/hive/eval.nix

@@ -38,19 +38,25 @@ let
     else if uncheckedHive ? network then uncheckedHive.network
     else {};
 
+  uncheckedRegistries = if uncheckedHive ? registry then uncheckedHive.registry else {};
+
   # The final hive will always have the meta key instead of network.
   hive = let
     userMeta = (lib.modules.evalModules {
       modules = [ colmenaOptions.metaOptions uncheckedUserMeta ];
     }).config;
 
+    registry = (lib.modules.evalModules {
+      modules = [ colmenaOptions.registryOptions  { registry = uncheckedRegistries; } ];
+    }).config.registry;
+
     mergedHive =
       assert lib.assertMsg (!(uncheckedHive ? __schema)) ''
         You cannot pass in an already-evaluated Hive into the evaluator.
 
         Hint: Use the `colmenaHive` output instead of `colmena`.
       '';
-      removeAttrs (defaultHive // uncheckedHive) [ "meta" "network" ];
+      removeAttrs (defaultHive // uncheckedHive) [ "meta" "network" "registry" ];
 
     meta = {
       meta =
@@ -58,7 +64,7 @@ let
         then userMeta // { nixpkgs = <nixpkgs>; }
         else userMeta;
     };
-  in mergedHive // meta;
+  in mergedHive // meta // { inherit registry; };
 
   configsFor = node: let
     nodeConfig = hive.${node};
@@ -112,14 +118,23 @@ let
   in mkNixpkgs "meta.nixpkgs" nixpkgsConf;
 
   lib = nixpkgs.lib;
-  reservedNames = [ "defaults" "network" "meta" ];
+  reservedNames = [ "defaults" "network" "meta" "registry" ];
 
-  evalNode = name: configs: let
+  evalNode = name: configs:
+  # Some help on error messages.
+  assert (lib.assertMsg (lib.hasAttrByPath [ "deployment" "systemType" ] hive.${name})
+  "${name} does not have a deployment system type!");
+  assert (lib.assertMsg (builtins.typeOf hive.registry == "set"))
+    "The hive's registry is not a set, but of type '${builtins.typeOf hive.registry}'";
+  assert (lib.assertMsg (lib.hasAttr hive.${name}.deployment.systemType hive.registry)
+    "${builtins.toJSON (hive.${name}.deployment.systemType)} does not exist in the registry of systems!");
+  let
+    # We cannot use `configs` because we need to access to the raw configuration fragment.
+    inherit (hive.registry.${hive.${name}.deployment.systemType}) evalConfig;
     npkgs =
       if hasAttr name hive.meta.nodeNixpkgs
       then mkNixpkgs "meta.nodeNixpkgs.${name}" hive.meta.nodeNixpkgs.${name}
       else nixpkgs;
-    evalConfig = import (npkgs.path + "/nixos/lib/eval-config.nix");
 
     # Here we need to merge the configurations in meta.nixpkgs
     # and in machine config.
@@ -139,17 +154,19 @@ let
       in
         lib.optional (!hasTypedConfig && length remainingKeys != 0)
         "The following Nixpkgs configuration keys set in meta.nixpkgs will be ignored: ${toString remainingKeys}";
-    };
+      } // lib.optionalAttrs (builtins.hasAttr "localSystem" npkgs || builtins.hasAttr "crossSystem" npkgs) {
+        nixpkgs.localSystem = lib.mkBefore npkgs.localSystem;
+        nixpkgs.crossSystem = lib.mkBefore npkgs.crossSystem;
+      };
   in evalConfig {
-    inherit (npkgs) system;
+    # This doesn't exist for `evalModules` the generic way.
+    # inherit (npkgs) system;
 
     modules = [
       nixpkgsModule
       colmenaModules.assertionModule
-      colmenaModules.keyChownModule
-      colmenaModules.keyServiceModule
       colmenaOptions.deploymentOptions
-      hive.defaults
+      (hive.registry.${hive.${name}.deployment.systemType}.defaults or hive.defaults)
     ] ++ configs;
     specialArgs = {
       inherit name;
@@ -179,9 +196,13 @@ let
     "allowApplyAll"
   ];
 
+  serializableSystemTypeConfigKeys = [
+    "supportsDeployment"
+  ];
+
 in rec {
   # Exported attributes
-  __schema = "v0";
+  __schema = "v0.20241006";
 
   nodes = listToAttrs (map (name: { inherit name; value = evalNode name (configsFor name); }) nodeNames);
   toplevel =         lib.mapAttrs (_: v: v.config.system.build.toplevel) nodes;
@@ -190,5 +211,9 @@ in rec {
   evalSelected =             names: lib.filterAttrs (name: _: elem name names) toplevel;
   evalSelectedDrvPaths =     names: lib.mapAttrs    (_: v: v.drvPath)          (evalSelected names);
   metaConfig = lib.filterAttrs (n: v: elem n metaConfigKeys) hive.meta;
-  introspect = f: f { inherit lib; pkgs = nixpkgs; nodes = uncheckedNodes; };
+  # We cannot perform a `metaConfigKeys`-style simple check here
+  # because registry is arbitrarily deep and may evaluate nixpkgs indirectly.
+  registryConfig = lib.mapAttrs (systemTypeName: systemType:
+    lib.filterAttrs (n: v: elem n serializableSystemTypeConfigKeys) systemType) hive.registry;
+  introspect = f: f { inherit lib; pkgs = nixpkgs; inherit nodes; };
 }

src/nix/hive/flake.nix

@@ -7,7 +7,7 @@
 
   outputs = { self, hive }: {
     processFlake = let
-      compatibleSchema = "v0";
+      compatibleSchema = "v0.20241006";
 
       # Evaluates a raw hive.
       #

src/nix/hive/mod.rs

@@ -8,6 +8,7 @@ use std::convert::AsRef;
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
 
+use const_format::formatcp;
 use tokio::process::Command;
 use tokio::sync::OnceCell;
 use validator::Validate;
@@ -15,13 +16,28 @@ use validator::Validate;
 use super::deployment::TargetNode;
 use super::{
     Flake, MetaConfig, NixExpression, NixFlags, NodeConfig, NodeFilter, NodeName,
-    ProfileDerivation, SerializedNixExpression, StorePath,
+    ProfileDerivation, RegistryConfig, SerializedNixExpression, StorePath,
 };
 use crate::error::{ColmenaError, ColmenaResult};
 use crate::job::JobHandle;
 use crate::util::{CommandExecution, CommandExt};
 use assets::Assets;
 
+/// The version of the Hive schema we are compatible with.
+///
+/// Currently we are tied to one specific version.
+const HIVE_SCHEMA: &str = "v0.20241006";
+
+/// The snippet to be used for `nix eval --apply`.
+const FLAKE_APPLY_SNIPPET: &str = formatcp!(
+    r#"with builtins; hive: assert (hive.__schema == "{}" || throw ''
+    The colmenaHive output (schema ${{hive.__schema}}) isn't compatible with this version of Colmena.
+
+    Hint: Use the same version of Colmena as in the Flake input.
+''); "#,
+    HIVE_SCHEMA
+);
+
 #[derive(Debug, Clone)]
 pub enum HivePath {
     /// A Nix Flake.
@@ -63,11 +79,33 @@ impl FromStr for HivePath {
     }
 }
 
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum EvaluationMethod {
+    /// Use nix-instantiate and specify the entire Nix expression.
+    ///
+    /// This is the default method.
+    ///
+    /// For flakes, we use `builtins.getFlakes`. Pure evaluation no longer works
+    /// with this method in Nix 2.21+.
+    NixInstantiate,
+
+    /// Use `nix eval --apply` on top of a flake.
+    ///
+    /// This can be activated with --experimental-flake-eval.
+    ///
+    /// In this method, we can no longer pull in our bundled assets and
+    /// the flake must expose a compatible `colmenaHive` output.
+    DirectFlakeEval,
+}
+
 #[derive(Debug)]
 pub struct Hive {
     /// Path to the hive.
     path: HivePath,
 
+    /// Method to evaluate the hive with.
+    evaluation_method: EvaluationMethod,
+
     /// Path to the context directory.
     ///
     /// Normally this is directory containing the "hive.nix"
@@ -87,6 +125,8 @@ pub struct Hive {
     nix_options: HashMap<String, String>,
 
     meta_config: OnceCell<MetaConfig>,
+
+    registry_config: OnceCell<RegistryConfig>,
 }
 
 struct NixInstantiate<'hive> {
@@ -134,12 +174,14 @@ impl Hive {
 
         Ok(Self {
             path,
+            evaluation_method: EvaluationMethod::NixInstantiate,
             context_dir,
             assets,
             show_trace: false,
             impure: false,
             nix_options: HashMap::new(),
             meta_config: OnceCell::new(),
+            registry_config: OnceCell::new(),
         })
     }
 
@@ -158,6 +200,25 @@ impl Hive {
             .await
     }
 
+    pub fn set_evaluation_method(&mut self, method: EvaluationMethod) {
+        if !self.is_flake() && method == EvaluationMethod::DirectFlakeEval {
+            return;
+        }
+
+        self.evaluation_method = method;
+    }
+
+    pub async fn get_registry_config(&self) -> ColmenaResult<&RegistryConfig> {
+        self.registry_config
+            .get_or_try_init(|| async {
+                self.nix_instantiate("hive.registryConfig")
+                    .eval()
+                    .capture_json()
+                    .await
+            })
+            .await
+    }
+
     pub fn set_show_trace(&mut self, value: bool) {
         self.show_trace = value;
     }
@@ -201,6 +262,9 @@ impl Hive {
     ) -> ColmenaResult<HashMap<NodeName, TargetNode>> {
         let mut node_configs = None;
 
+        log::info!("Enumerating systems...");
+        let registry = self.get_registry_config().await?;
+
         log::info!("Enumerating nodes...");
 
         let all_nodes = self.node_names().await?;
@@ -234,6 +298,24 @@ impl Hive {
             self.deployment_info_selected(&selected_nodes).await?
         };
 
+        for node_config in &node_configs {
+            if let Some(system_type) = node_config.1.system_type.as_ref() {
+                let Some(system_config) = registry.systems.get(system_type) else {
+                    // TODO: convert me to proper error?
+                    log::warn!("'{:?}' is not a known system type in the registry, double check your expressions!", system_type);
+                    return Err(ColmenaError::Unknown {
+                        message: "unknown system type".to_string(),
+                    });
+                };
+
+                if !system_config.supports_deployment {
+                    return Err(ColmenaError::UndeployableHost {
+                        node_name: node_config.0.to_string(),
+                    });
+                }
+            }
+        }
+
         let mut targets = HashMap::new();
         let mut n_ssh = 0;
         for node in selected_nodes.into_iter() {
@@ -421,7 +503,10 @@ impl Hive {
 
     /// Returns the base expression from which the evaluated Hive can be used.
     fn get_base_expression(&self) -> String {
-        self.assets.get_base_expression()
+        match self.evaluation_method {
+            EvaluationMethod::NixInstantiate => self.assets.get_base_expression(),
+            EvaluationMethod::DirectFlakeEval => FLAKE_APPLY_SNIPPET.to_string(),
+        }
     }
 
     /// Returns whether this Hive is a flake.
@@ -444,6 +529,11 @@ impl<'hive> NixInstantiate<'hive> {
     }
 
     fn instantiate(&self) -> Command {
+        // TODO: Better error handling
+        if self.hive.evaluation_method == EvaluationMethod::DirectFlakeEval {
+            panic!("Instantiation is not supported with DirectFlakeEval");
+        }
+
         let mut command = Command::new("nix-instantiate");
 
         if self.hive.is_flake() {
@@ -462,17 +552,48 @@ impl<'hive> NixInstantiate<'hive> {
     }
 
     fn eval(self) -> Command {
-        let mut command = self.instantiate();
         let flags = self.hive.nix_flags();
-        command
+
-            .arg("--eval")
+        match self.hive.evaluation_method {
-            .arg("--json")
+            EvaluationMethod::NixInstantiate => {
-            .arg("--strict")
+                let mut command = self.instantiate();
-            // Ensures the derivations are instantiated
+
-            // Required for system profile evaluation and IFD
+                command
-            .arg("--read-write-mode")
+                    .arg("--eval")
-            .args(flags.to_args());
+                    .arg("--json")
-        command
+                    .arg("--strict")
+                    // Ensures the derivations are instantiated
+                    // Required for system profile evaluation and IFD
+                    .arg("--read-write-mode")
+                    .args(flags.to_args());
+
+                command
+            }
+            EvaluationMethod::DirectFlakeEval => {
+                let mut command = Command::new("nix");
+                let flake = if let HivePath::Flake(flake) = self.hive.path() {
+                    flake
+                } else {
+                    panic!("The DirectFlakeEval evaluation method only support flakes");
+                };
+
+                let hive_installable = format!("{}#colmenaHive", flake.uri());
+
+                let mut full_expression = self.hive.get_base_expression();
+                full_expression += &self.expression;
+
+                command
+                    .arg("eval") // nix eval
+                    .args(["--extra-experimental-features", "flakes nix-command"])
+                    .arg(hive_installable)
+                    .arg("--json")
+                    .arg("--apply")
+                    .arg(&full_expression)
+                    .args(flags.to_args());
+
+                command
+            }
+        }
     }
 
     async fn instantiate_with_builders(self) -> ColmenaResult<Command> {

src/nix/hive/options.nix

@@ -1,18 +1,17 @@
 with builtins; rec {
   keyType = { lib, name, config, ... }: let
     inherit (lib) types;
-    mdDoc = lib.mdDoc or (md: md);
   in {
     options = {
       name = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           File name of the key.
         '';
         default = name;
         type = types.str;
       };
       text = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           Content of the key.
           One of `text`, `keyCommand` and `keyFile` must be set.
         '';
@@ -20,7 +19,7 @@ with builtins; rec {
         type = types.nullOr types.str;
       };
       keyFile = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           Path of the local file to read the key from.
           One of `text`, `keyCommand` and `keyFile` must be set.
         '';
@@ -29,7 +28,7 @@ with builtins; rec {
         type = types.nullOr types.path;
       };
       keyCommand = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           Command to run to generate the key.
           One of `text`, `keyCommand` and `keyFile` must be set.
         '';
@@ -39,14 +38,14 @@ with builtins; rec {
         in types.nullOr nonEmptyList;
       };
       destDir = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           Destination directory on the host.
         '';
         default = "/run/keys";
         type = types.path;
       };
       path = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           Full path to the destination.
         '';
         default = "${config.destDir}/${config.name}";
@@ -54,28 +53,28 @@ with builtins; rec {
         internal = true;
       };
       user = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           The group that will own the file.
         '';
         default = "root";
         type = types.str;
       };
       group = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           The group that will own the file.
         '';
         default = "root";
         type = types.str;
       };
       permissions = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           Permissions to set for the file.
         '';
         default = "0600";
         type = types.str;
       };
       uploadAt = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           When to upload the keys.
 
           - pre-activation (default): Upload the keys before activating the new system profile.
@@ -94,12 +93,19 @@ with builtins; rec {
   # Largely compatible with NixOps/Morph.
   deploymentOptions = { name, lib, ... }: let
     inherit (lib) types;
-    mdDoc = lib.mdDoc or (md: md);
   in {
     options = {
       deployment = {
-        targetHost = lib.mkOption {
+        systemType = lib.mkOption {
           description = mdDoc ''
+            System type used for this node, e.g. NixOS.
+          '';
+          default = "nixos";
+          # TODO: enum among all registered systems?
+          type = types.str;
+        };
+        targetHost = lib.mkOption {
+          description = ''
             The target SSH node for deployment.
 
             By default, the node's attribute name will be used.
@@ -109,7 +115,7 @@ with builtins; rec {
           default = name;
         };
         targetPort = lib.mkOption {
-          description = mdDoc ''
+          description = ''
             The target SSH port for deployment.
 
             By default, the port is the standard port (22) or taken
@@ -119,7 +125,7 @@ with builtins; rec {
           default = null;
         };
         targetUser = lib.mkOption {
-          description = mdDoc ''
+          description = ''
             The user to use to log into the remote node. If set to null, the
             target user will not be specified in SSH invocations.
           '';
@@ -127,7 +133,7 @@ with builtins; rec {
           default = "root";
         };
         allowLocalDeployment = lib.mkOption {
-          description = mdDoc ''
+          description = ''
             Allow the configuration to be applied locally on the host running
             Colmena.
 
@@ -144,7 +150,7 @@ with builtins; rec {
           default = false;
         };
         buildOnTarget = lib.mkOption {
-          description = mdDoc ''
+          description = ''
             Whether to build the system profiles on the target node itself.
 
             When enabled, Colmena will copy the derivation to the target
@@ -164,7 +170,7 @@ with builtins; rec {
           default = false;
         };
         tags = lib.mkOption {
-          description = mdDoc ''
+          description = ''
             A list of tags for the node.
 
             Can be used to select a group of nodes for deployment.
@@ -173,7 +179,7 @@ with builtins; rec {
           default = [];
         };
         keys = lib.mkOption {
-          description = mdDoc ''
+          description = ''
             A set of secrets to be deployed to the node.
 
             Secrets are transferred to the node out-of-band and
@@ -183,7 +189,7 @@ with builtins; rec {
           default = {};
         };
         replaceUnknownProfiles = lib.mkOption {
-          description = mdDoc ''
+          description = ''
             Allow a configuration to be applied to a host running a profile we
             have no knowledge of. By setting this option to false, you reduce
             the likelyhood of rolling back changes made via another Colmena user.
@@ -199,7 +205,7 @@ with builtins; rec {
           default = true;
         };
         privilegeEscalationCommand = lib.mkOption {
-          description = mdDoc ''
+          description = ''
             Command to use to elevate privileges when activating the new profiles on SSH hosts.
 
             This is used on SSH hosts when `deployment.targetUser` is not `root`.
@@ -209,7 +215,7 @@ with builtins; rec {
           default = [ "sudo" "-H" "--" ];
         };
         sshOptions = lib.mkOption {
-          description = mdDoc ''
+          description = ''
             Extra SSH options to pass to the SSH command.
           '';
           type = types.listOf types.str;
@@ -218,32 +224,77 @@ with builtins; rec {
       };
     };
   };
+  # Options for a registered system type
+  systemTypeOptions = { name, lib, ... }: let
+    inherit (lib) types;
+    mdDoc = lib.mdDoc or lib.id;
+  in
+  {
+    options = {
+      evalConfig = lib.mkOption {
+        description = mdDoc ''
+          Evaluation function which share the same interface as `nixos/lib/eval-config.nix`
+          which can be tailored to your own usecases or to target another type of system,
+          e.g. nix-darwin.
+        '';
+        type = types.functionTo types.unspecified;
+      };
+      supportsDeployment = lib.mkOption {
+        description = mdDoc ''
+          Whether this system type supports deployment or not.
+
+          If it supports deployment, it needs to have appropriate activation code,
+          refer to how to write custom activators.
+        '';
+        default = name == "nixos";
+        defaultText = "If a NixOS system, then true, otherwise false by default";
+      };
+      defaults = lib.mkOption {
+        description = mdDoc ''
+          Default configuration for that system type.
+        '';
+        type = types.functionTo types.unspecified;
+        default = _: {};
+      };
+    };
+  };
+  registryOptions = { lib, ... }: let
+    inherit (lib) types;
+    mdDoc = lib.mdDoc or lib.id;
+  in
+  {
+    options.registry = lib.mkOption {
+      description = mdDoc ''
+        A registry of all system types.
+      '';
+      type = types.attrsOf (types.submodule systemTypeOptions);
+    };
+  };
   # Hive-wide options
   metaOptions = { lib, ... }: let
     inherit (lib) types;
-    mdDoc = lib.mdDoc or (md: md);
   in {
     options = {
       name = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           The name of the configuration.
         '';
         type = types.str;
         default = "hive";
       };
       description = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           A short description for the configuration.
         '';
         type = types.str;
         default = "A Colmena Hive";
       };
       nixpkgs = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           The pinned Nixpkgs package set. Accepts one of the following:
 
           - A path to a Nixpkgs checkout
-          - The Nixpkgs lambda (e.g., import \<nixpkgs\>)
+          - The Nixpkgs lambda (e.g., import <nixpkgs>)
           - An initialized Nixpkgs attribute set
 
           This option must be specified when using Flakes.
@@ -252,21 +303,21 @@ with builtins; rec {
         default = null;
       };
       nodeNixpkgs = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           Node-specific Nixpkgs pins.
         '';
         type = types.attrsOf types.unspecified;
         default = {};
       };
       nodeSpecialArgs = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           Node-specific special args.
         '';
         type = types.attrsOf types.unspecified;
         default = {};
       };
       machinesFile = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           Use the machines listed in this file when building this hive configuration.
 
           If your Colmena host has nix configured to allow for remote builds
@@ -290,7 +341,7 @@ with builtins; rec {
         type = types.nullOr types.path;
       };
       specialArgs = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           A set of special arguments to be passed to NixOS modules.
 
           This will be merged into the `specialArgs` used to evaluate
@@ -300,7 +351,7 @@ with builtins; rec {
         type = types.attrsOf types.unspecified;
       };
       allowApplyAll = lib.mkOption {
-        description = mdDoc ''
+        description = ''
           Whether to allow deployments without a node filter set.
 
           If set to false, a node filter must be specified with `--on` when

src/nix/key.rs

@@ -87,14 +87,14 @@ pub struct Key {
     #[serde(flatten)]
     source: KeySource,
 
-    #[validate(custom = "validate_dest_dir")]
+    #[validate(custom(function = "validate_dest_dir"))]
     #[serde(rename = "destDir")]
     dest_dir: PathBuf,
 
-    #[validate(custom = "validate_unix_name")]
+    #[validate(custom(function = "validate_unix_name"))]
     user: String,
 
-    #[validate(custom = "validate_unix_name")]
+    #[validate(custom(function = "validate_unix_name"))]
     group: String,
 
     permissions: String,

src/nix/mod.rs

@@ -55,6 +55,9 @@ pub struct NodeName(#[serde(deserialize_with = "NodeName::deserialize")] String)
 
 #[derive(Debug, Clone, Validate, Deserialize)]
 pub struct NodeConfig {
+    #[serde(rename = "systemType")]
+    system_type: Option<String>,
+
     #[serde(rename = "targetHost")]
     target_host: Option<String>,
 
@@ -81,7 +84,7 @@ pub struct NodeConfig {
     #[serde(rename = "sshOptions")]
     extra_ssh_options: Vec<String>,
 
-    #[validate(custom = "validate_keys")]
+    #[validate(custom(function = "validate_keys"))]
     keys: HashMap<String, Key>,
 }
 
@@ -94,6 +97,18 @@ pub struct MetaConfig {
     pub machines_file: Option<String>,
 }
 
+#[derive(Debug, Clone, Validate, Deserialize)]
+pub struct SystemTypeConfig {
+    #[serde(rename = "supportsDeployment")]
+    pub supports_deployment: bool,
+}
+
+#[derive(Debug, Clone, Validate, Deserialize)]
+pub struct RegistryConfig {
+    #[serde(flatten)]
+    pub systems: HashMap<String, SystemTypeConfig>,
+}
+
 /// Nix CLI flags.
 #[derive(Debug, Clone, Default)]
 pub struct NixFlags {

src/progress/mod.rs

@@ -7,6 +7,8 @@
 pub mod plain;
 pub mod spinner;
 
+use std::io::IsTerminal;
+
 use async_trait::async_trait;
 use tokio::sync::mpsc::{self, UnboundedReceiver as TokioReceiver, UnboundedSender as TokioSender};
 
@@ -90,7 +92,7 @@ pub enum LineStyle {
 
 impl SimpleProgressOutput {
     pub fn new(verbose: bool) -> Self {
-        let tty = atty::is(atty::Stream::Stdout);
+        let tty = std::io::stdout().is_terminal();
 
         if verbose || !tty {
             Self::Plain(PlainOutput::new())