treewide: use attrs instead of list for types.loaOf options

nixos/modules/services/monitoring/datadog-agent.nix

@@ -22,9 +22,9 @@ let
   # Generate Datadog configuration files for each configured checks.
   # This works because check configurations have predictable paths,
   # and because JSON is a valid subset of YAML.
-  makeCheckConfigs = entries: mapAttrsToList (name: conf: {
-    source = pkgs.writeText "${name}-check-conf.yaml" (builtins.toJSON conf);
-    target = "datadog-agent/conf.d/${name}.d/conf.yaml";
+  makeCheckConfigs = entries: mapAttrs' (name: conf: {
+    name = "datadog-agent/conf.d/${name}.d/conf.yaml";
+    value.source = pkgs.writeText "${name}-check-conf.yaml" (builtins.toJSON conf);
   }) entries;
 
   defaultChecks = {
@@ -34,10 +34,11 @@ let
 
   # Assemble all check configurations and the top-level agent
   # configuration.
-  etcfiles = with pkgs; with builtins; [{
-    source = writeText "datadog.yaml" (toJSON ddConf);
-    target = "datadog-agent/datadog.yaml";
-  }] ++ makeCheckConfigs (cfg.checks // defaultChecks);
+  etcfiles = with pkgs; with builtins;
+  { "datadog-agent/datadog.yaml" = {
+      source = writeText "datadog.yaml" (toJSON ddConf);
+    };
+  } // makeCheckConfigs (cfg.checks // defaultChecks);
 
   # Apply the configured extraIntegrations to the provided agent
   # package. See the documentation of `dd-agent/integrations-core.nix`
@@ -204,7 +205,7 @@ in {
   config = mkIf cfg.enable {
     environment.systemPackages = [ datadogPkg pkgs.sysstat pkgs.procps pkgs.iproute ];
 
-    users.extraUsers.datadog = {
+    users.users.datadog = {
       description = "Datadog Agent User";
       uid = config.ids.uids.datadog;
       group = "datadog";
@@ -212,7 +213,7 @@ in {
       createHome = true;
     };
 
-    users.extraGroups.datadog.gid = config.ids.gids.datadog;
+    users.groups.datadog.gid = config.ids.gids.datadog;
 
     systemd.services = let
       makeService = attrs: recursiveUpdate {
@@ -224,7 +225,7 @@ in {
           Restart = "always";
           RestartSec = 2;
         };
-        restartTriggers = [ datadogPkg ] ++ map (etc: etc.source) etcfiles;
+        restartTriggers = [ datadogPkg ] ++ attrNames etcfiles;
       } attrs;
     in {
       datadog-agent = makeService {