Major overhaul of the nix side of things.

README.md

@@ -56,15 +56,19 @@ which should contain a `default.nix` file which functions as the entrance point.
 A simple System Manager module could look something like this:
 
 ```nix
-{ config, lib, pkgs, ... }:
+{ config
-let
+, lib
-  etcFiles = {
+, pkgs
+, ... }:
+
+{
+  config.system-manager = {
+    environment.etc = {
       "foo.conf".text = ''
         launch_the_rockets = true
       '';
     };
-
+    systemd.services = {
-  services = {
       foo = {
         enable = true;
         serviceConfig = {
@@ -77,15 +81,6 @@ let
         '';
       };
     };
-in
-{
-  config = {
-    system-manager = {
-      etcFiles = lib.attrNames etcFiles;
-      services = lib.attrNames services;
-    };
-    environment.etc = etcFiles;
-    systemd = { inherit services; };
   };
 }
 ```

nix/lib.nix

@@ -16,6 +16,7 @@ in
       pkgs = nixpkgs.legacyPackages.${system};
       inherit (self.packages.${system}) system-manager;
 
+      # TODO can we call lib.evalModules directly instead of building a NixOS system?
       nixosConfig = (lib.nixosSystem {
         inherit system;
         modules = [
@@ -33,17 +34,13 @@ in
         else lib.showWarnings nixosConfig.warnings drv;
 
       services =
-        lib.listToAttrs
+        lib.mapAttrs'
-          (map
+          (unitName: unit:
-            (name:
+            lib.nameValuePair unitName {
-              let
-                serviceName = "${name}.service";
-              in
-              lib.nameValuePair serviceName {
               storePath =
-                  ''${nixosConfig.systemd.units."${serviceName}".unit}/${serviceName}'';
+                ''${unit.unit}/${unitName}'';
             })
-            nixosConfig.system-manager.services);
+          nixosConfig.system-manager.systemd.units;
 
       servicesPath = pkgs.writeTextFile {
         name = "services";
@@ -54,8 +51,6 @@ in
       # TODO: handle globbing
       etcFiles =
         let
-          isManaged = name: lib.elem name nixosConfig.system-manager.etcFiles;
-
           addToStore = name: file: pkgs.runCommandLocal "${name}-etc-link" { } ''
             mkdir -p "$out/$(dirname "${file.target}")"
             ln -s "${file.source}" "$out/${file.target}"
@@ -68,8 +63,8 @@ in
           '';
 
           filteredEntries = lib.filterAttrs
-            (name: etcFile: etcFile.enable && isManaged name)
+            (_name: etcFile: etcFile.enable)
-            nixosConfig.environment.etc;
+            nixosConfig.system-manager.environment.etc;
 
           srcDrvs = lib.mapAttrs addToStore filteredEntries;
 

nix/modules/default.nix

@@ -2,37 +2,10 @@
 , pkgs
 , ...
 }:
-let
+{
-  services =
+  config = {
-    lib.listToAttrs
+    system-manager = {
-      (lib.flip lib.genList 10 (ix:
+      environment.etc = {
-        lib.nameValuePair "service-${toString ix}"
-          {
-            enable = true;
-            description = "service-${toString ix}";
-            wants = [ "network-online.target" ];
-            after = [
-              "network-online.target"
-              "avahi-daemon.service"
-              "chrony.service"
-              "nss-lookup.target"
-              "tinc.service"
-              "pulseaudio.service"
-            ];
-            serviceConfig = {
-              Type = "oneshot";
-              RemainAfterExit = true;
-              ExecReload = "${lib.getBin pkgs.coreutils}/bin/true";
-            };
-            wantedBy = [ "multi-user.target" ];
-            requiredBy = lib.mkIf (ix > 5) [ "service-0.service" ];
-            script = ''
-              sleep ${if ix > 5 then "2" else "1"}
-            '';
-          })
-      );
-
-  etcFiles = {
         foo = {
           text = ''
             This is just a test!
@@ -40,6 +13,10 @@ let
           target = "foo_test";
         };
 
+        "foo.conf".text = ''
+          launch_the_rockets = true
+        '';
+
         "baz/bar/foo2" = {
           text = ''
             Another test!
@@ -72,14 +49,34 @@ let
           source = "/run/systemd/system/";
         };
       };
-in
+      systemd.services =
-{
+        lib.listToAttrs
-  config = {
+          (lib.flip lib.genList 10 (ix:
-    system-manager = {
+            lib.nameValuePair "service-${toString ix}"
-      etcFiles = lib.attrNames etcFiles;
+              {
-      services = lib.attrNames services;
+                enable = true;
+                description = "service-${toString ix}";
+                wants = [ "network-online.target" ];
+                after = [
+                  "network-online.target"
+                  "avahi-daemon.service"
+                  "chrony.service"
+                  "nss-lookup.target"
+                  "tinc.service"
+                  "pulseaudio.service"
+                ];
+                serviceConfig = {
+                  Type = "oneshot";
+                  RemainAfterExit = true;
+                  ExecReload = "${lib.getBin pkgs.coreutils}/bin/true";
+                };
+                wantedBy = [ "multi-user.target" ];
+                requiredBy = lib.mkIf (ix > 5) [ "service-0.service" ];
+                script = ''
+                  sleep ${if ix > 5 then "2" else "1"}
+                '';
+              })
+          );
     };
-    environment.etc = etcFiles;
-    systemd = { inherit services; };
   };
 }

nix/modules/etc.nix

@@ -0,0 +1,118 @@
+{ lib
+, pkgs
+, ...
+}:
+{
+  options.system-manager = {
+    environment.etc = lib.mkOption {
+      default = { };
+      example = lib.literalExpression ''
+        { example-configuration-file =
+            { source = "/nix/store/.../etc/dir/file.conf.example";
+              mode = "0440";
+            };
+          "default/useradd".text = "GROUP=100 ...";
+        }
+      '';
+      description = lib.mdDoc ''
+        Set of files that have to be linked in {file}`/etc`.
+      '';
+
+      type = lib.types.attrsOf (lib.types.submodule (
+        { name, config, options, ... }:
+        {
+          options = {
+
+            enable = lib.mkOption {
+              type = lib.types.bool;
+              default = true;
+              description = lib.mdDoc ''
+                Whether this /etc file should be generated.  This
+                option allows specific /etc files to be disabled.
+              '';
+            };
+
+            target = lib.mkOption {
+              type = lib.types.str;
+              description = lib.mdDoc ''
+                Name of symlink (relative to
+                {file}`/etc`).  Defaults to the attribute
+                name.
+              '';
+            };
+
+            text = lib.mkOption {
+              default = null;
+              type = lib.types.nullOr lib.types.lines;
+              description = lib.mdDoc "Text of the file.";
+            };
+
+            source = lib.mkOption {
+              type = lib.types.path;
+              description = lib.mdDoc "Path of the source file.";
+            };
+
+            mode = lib.mkOption {
+              type = lib.types.str;
+              default = "symlink";
+              example = "0600";
+              description = lib.mdDoc ''
+                If set to something else than `symlink`,
+                the file is copied instead of symlinked, with the given
+                file mode.
+              '';
+            };
+
+            uid = lib.mkOption {
+              default = 0;
+              type = lib.types.int;
+              description = lib.mdDoc ''
+                UID of created file. Only takes effect when the file is
+                copied (that is, the mode is not 'symlink').
+              '';
+            };
+
+            gid = lib.mkOption {
+              default = 0;
+              type = lib.types.int;
+              description = lib.mdDoc ''
+                GID of created file. Only takes effect when the file is
+                copied (that is, the mode is not 'symlink').
+              '';
+            };
+
+            user = lib.mkOption {
+              default = "+${toString config.uid}";
+              type = lib.types.str;
+              description = lib.mdDoc ''
+                User name of created file.
+                Only takes effect when the file is copied (that is, the mode is not 'symlink').
+                Changing this option takes precedence over `uid`.
+              '';
+            };
+
+            group = lib.mkOption {
+              default = "+${toString config.gid}";
+              type = lib.types.str;
+              description = lib.mdDoc ''
+                Group name of created file.
+                Only takes effect when the file is copied (that is, the mode is not 'symlink').
+                Changing this option takes precedence over `gid`.
+              '';
+            };
+
+          };
+
+          config = {
+            target = lib.mkDefault name;
+            source = lib.mkIf (config.text != null) (
+              let name' = "etc-" + baseNameOf name;
+              in lib.mkDerivedConfig options.text (pkgs.writeText name')
+            );
+          };
+
+        }
+      ));
+    };
+  };
+}

nix/modules/system-manager.nix

@@ -1,20 +1,14 @@
 { lib
 , config
-, pkgs
 , ...
 }:
 {
+  imports = [
+    ./etc.nix
+    ./systemd.nix
+  ];
+
   options.system-manager = {
-    services = lib.mkOption {
-      type = with lib.types; listOf str;
-      default = [ ];
-    };
-
-    etcFiles = lib.mkOption {
-      type = with lib.types; listOf str;
-      default = [ ];
-    };
-
     allowAnyDistro = lib.mkEnableOption "the usage of system-manager on untested distributions";
 
     preActivationAssertions = lib.mkOption {
@@ -44,28 +38,6 @@
     };
     system.stateVersion = lib.mkDefault lib.trivial.release;
 
-    assertions =
-      lib.flip map config.system-manager.etcFiles
-        (entry:
-          {
-            assertion = lib.hasAttr entry config.environment.etc;
-            message = lib.concatStringsSep " " [
-              "The entry ${entry} that was passed to system-manager.etcFiles"
-              "is not present in environment.etc"
-            ];
-          }
-        ) ++
-      lib.flip map config.system-manager.services
-        (entry:
-          {
-            assertion = lib.hasAttr entry config.systemd.services;
-            message = lib.concatStringsSep " " [
-              "The entry ${entry} that was passed to system-manager.services"
-              "is not present in systemd.services"
-            ];
-          }
-        );
-
     system-manager.preActivationAssertions = {
       osVersion =
         let
@@ -86,66 +58,5 @@
           '';
         };
     };
-
-    # Add the system directory for systemd
-    system-manager.etcFiles = [ "systemd/system" ];
-
-    environment.etc =
-      let
-        allowCollisions = false;
-
-        enabledUnits =
-          lib.filterAttrs
-            (name: _: lib.elem
-              name
-              (map (name: "${name}.service") config.system-manager.services))
-            config.systemd.units;
-      in
-      {
-        "systemd/system".source = lib.mkForce (pkgs.runCommand "system-manager-units"
-          {
-            preferLocalBuild = true;
-            allowSubstitutes = false;
-          }
-          ''
-            mkdir -p $out
-
-            for i in ${toString (lib.mapAttrsToList (n: v: v.unit) enabledUnits)}; do
-              fn=$(basename $i/*)
-              if [ -e $out/$fn ]; then
-                if [ "$(readlink -f $i/$fn)" = /dev/null ]; then
-                  ln -sfn /dev/null $out/$fn
-                else
-                  ${if allowCollisions then ''
-                    mkdir -p $out/$fn.d
-                    ln -s $i/$fn $out/$fn.d/overrides.conf
-                  '' else ''
-                    echo "Found multiple derivations configuring $fn!"
-                    exit 1
-                  ''}
-                fi
-              else
-                ln -fs $i/$fn $out/
-              fi
-            done
-
-            ${lib.concatStrings (
-              lib.mapAttrsToList (name: unit:
-                lib.concatMapStrings (name2: ''
-                  mkdir -p $out/'${name2}.wants'
-                  ln -sfn '../${name}' $out/'${name2}.wants'/
-                '') (unit.wantedBy or [])
-              ) enabledUnits)}
-
-            ${lib.concatStrings (
-              lib.mapAttrsToList (name: unit:
-                lib.concatMapStrings (name2: ''
-                  mkdir -p $out/'${name2}.requires'
-                  ln -sfn '../${name}' $out/'${name2}.requires'/
-                '') (unit.requiredBy or [])
-              ) enabledUnits)}
-          ''
-        );
-      };
   };
 }

nix/modules/systemd.nix

@@ -0,0 +1,192 @@
+{ lib
+, config
+, pkgs
+, utils
+, ...
+}:
+
+let
+  cfg = config.system-manager.systemd;
+
+  inherit (utils) systemdUtils;
+  systemd-lib = utils.systemdUtils.lib;
+in
+{
+  options.system-manager.systemd = {
+
+    units = lib.mkOption {
+      description = lib.mdDoc "Definition of systemd units.";
+      default = { };
+      type = systemdUtils.types.units;
+    };
+
+    packages = lib.mkOption {
+      default = [ ];
+      type = lib.types.listOf lib.types.package;
+      example = lib.literalExpression "[ pkgs.systemd-cryptsetup-generator ]";
+      description = lib.mdDoc "Packages providing systemd units and hooks.";
+    };
+
+    targets = lib.mkOption {
+      default = { };
+      type = systemdUtils.types.targets;
+      description = lib.mdDoc "Definition of systemd target units.";
+    };
+
+    services = lib.mkOption {
+      default = { };
+      type = systemdUtils.types.services;
+      description = lib.mdDoc "Definition of systemd service units.";
+    };
+
+    sockets = lib.mkOption {
+      default = { };
+      type = systemdUtils.types.sockets;
+      description = lib.mdDoc "Definition of systemd socket units.";
+    };
+
+    timers = lib.mkOption {
+      default = { };
+      type = systemdUtils.types.timers;
+      description = lib.mdDoc "Definition of systemd timer units.";
+    };
+
+    paths = lib.mkOption {
+      default = { };
+      type = systemdUtils.types.paths;
+      description = lib.mdDoc "Definition of systemd path units.";
+    };
+
+    mounts = lib.mkOption {
+      default = [ ];
+      type = systemdUtils.types.mounts;
+      description = lib.mdDoc ''
+        Definition of systemd mount units.
+        This is a list instead of an attrSet, because systemd mandates the names to be derived from
+        the 'where' attribute.
+      '';
+    };
+
+    automounts = lib.mkOption {
+      default = [ ];
+      type = systemdUtils.types.automounts;
+      description = lib.mdDoc ''
+        Definition of systemd automount units.
+        This is a list instead of an attrSet, because systemd mandates the names to be derived from
+        the 'where' attribute.
+      '';
+    };
+
+    slices = lib.mkOption {
+      default = { };
+      type = systemdUtils.types.slices;
+      description = lib.mdDoc "Definition of slice configurations.";
+    };
+
+    generators = lib.mkOption {
+      type = lib.types.attrsOf lib.types.path;
+      default = { };
+      example = { systemd-gpt-auto-generator = "/dev/null"; };
+      description = lib.mdDoc ''
+        Definition of systemd generators.
+        For each `NAME = VALUE` pair of the attrSet, a link is generated from
+        `/etc/systemd/system-generators/NAME` to `VALUE`.
+      '';
+    };
+
+    shutdown = lib.mkOption {
+      type = lib.types.attrsOf lib.types.path;
+      default = { };
+      description = lib.mdDoc ''
+        Definition of systemd shutdown executables.
+        For each `NAME = VALUE` pair of the attrSet, a link is generated from
+        `/etc/systemd/system-shutdown/NAME` to `VALUE`.
+      '';
+    };
+  };
+
+  config = {
+    system-manager = {
+      systemd = {
+        timers =
+          lib.mapAttrs
+            (name: service:
+              {
+                wantedBy = [ "timers.target" ];
+                timerConfig.OnCalendar = service.startAt;
+              })
+            (lib.filterAttrs (name: service: service.enable && service.startAt != [ ]) cfg.services);
+
+        units =
+          lib.mapAttrs' (n: v: lib.nameValuePair "${n}.path" (systemd-lib.pathToUnit n v)) cfg.paths
+          // lib.mapAttrs' (n: v: lib.nameValuePair "${n}.service" (systemd-lib.serviceToUnit n v)) cfg.services
+          // lib.mapAttrs' (n: v: lib.nameValuePair "${n}.slice" (systemd-lib.sliceToUnit n v)) cfg.slices
+          // lib.mapAttrs' (n: v: lib.nameValuePair "${n}.socket" (systemd-lib.socketToUnit n v)) cfg.sockets
+          // lib.mapAttrs' (n: v: lib.nameValuePair "${n}.target" (systemd-lib.targetToUnit n v)) cfg.targets
+          // lib.mapAttrs' (n: v: lib.nameValuePair "${n}.timer" (systemd-lib.timerToUnit n v)) cfg.timers
+          // lib.listToAttrs (map
+            (v:
+              let n = utils.escapeSystemdPath v.where;
+              in lib.nameValuePair "${n}.mount" (systemd-lib.mountToUnit n v))
+            cfg.mounts)
+          // lib.listToAttrs (map
+            (v:
+              let n = utils.escapeSystemdPath v.where;
+              in lib.nameValuePair "${n}.automount" (systemd-lib.automountToUnit n v))
+            cfg.automounts);
+      };
+
+      environment.etc =
+        let
+          allowCollisions = false;
+
+          enabledUnits = cfg.units;
+        in
+        {
+          "systemd/system".source = pkgs.runCommand "system-manager-units"
+            {
+              preferLocalBuild = true;
+              allowSubstitutes = false;
+            }
+            ''
+              mkdir -p $out
+
+              for i in ${toString (lib.mapAttrsToList (n: v: v.unit) enabledUnits)}; do
+                fn=$(basename $i/*)
+                if [ -e $out/$fn ]; then
+                  if [ "$(readlink -f $i/$fn)" = /dev/null ]; then
+                    ln -sfn /dev/null $out/$fn
+                  else
+                    ${if allowCollisions then ''
+                      mkdir -p $out/$fn.d
+                      ln -s $i/$fn $out/$fn.d/overrides.conf
+                    '' else ''
+                      echo "Found multiple derivations configuring $fn!"
+                      exit 1
+                    ''}
+                  fi
+                else
+                  ln -fs $i/$fn $out/
+                fi
+              done
+
+              ${lib.concatStrings (
+                lib.mapAttrsToList (name: unit:
+                  lib.concatMapStrings (name2: ''
+                    mkdir -p $out/'${name2}.wants'
+                    ln -sfn '../${name}' $out/'${name2}.wants'/
+                  '') (unit.wantedBy or [])
+                ) enabledUnits)}
+
+              ${lib.concatStrings (
+                lib.mapAttrsToList (name: unit:
+                  lib.concatMapStrings (name2: ''
+                    mkdir -p $out/'${name2}.requires'
+                    ln -sfn '../${name}' $out/'${name2}.requires'/
+                  '') (unit.requiredBy or [])
+                ) enabledUnits)}
+            '';
+        };
+    };
+  };
+}