From 4e51977ae014e26e345304eb405e35a99dbf64f6 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Wed, 12 Mar 2025 23:35:56 +0000
Subject: [PATCH] provide `properties` attr to services

properties are similar to outputs, but are different in that they are
fixed values (do not change) and are present even when the service is
down

if the attribute is present and an attrset, this will write the
equivalent recursive directory structure to $out/.properties/
---
 pkgs/liminix-tools/services/builder.sh  | 10 ++++++++++
 pkgs/liminix-tools/services/default.nix | 11 ++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/pkgs/liminix-tools/services/builder.sh b/pkgs/liminix-tools/services/builder.sh
index 47587c6..7a00b37 100644
--- a/pkgs/liminix-tools/services/builder.sh
+++ b/pkgs/liminix-tools/services/builder.sh
@@ -1,5 +1,15 @@
 source $stdenv/setup
 mkdir -p $out/${name}
+
+writepath(){
+    mkdir -p $(dirname $1)
+    echo $2 > $1
+}
+if test -n "$propertiesText"; then
+    mkdir $out/.properties
+    ( cd $out/.properties; eval "$propertiesText" )
+fi
+
 echo $serviceType > $out/${name}/type
 mkdir -p $out/${name}/dependencies.d
 echo $buildInputs > $out/buildInputs
diff --git a/pkgs/liminix-tools/services/default.nix b/pkgs/liminix-tools/services/default.nix
index 79b4a8f..6e11a32 100644
--- a/pkgs/liminix-tools/services/default.nix
+++ b/pkgs/liminix-tools/services/default.nix
@@ -8,6 +8,8 @@
 let
   prefix = "/run/services/outputs";
   output = service: name: "${prefix}/${service.name}/${name}";
+  inherit (lib.attrsets) mapAttrsRecursive collect;
+  inherit (lib.strings) concatStringsSep;
   serviceScript = commands: ''
     #!/bin/sh
     exec 2>&1
@@ -38,6 +40,7 @@ let
       buildInputs ? [ ],
       restart-on-upgrade ? false,
       controller ? null,
+      properties ? {}
     }:
     stdenvNoCC.mkDerivation {
       # we use stdenvNoCC to avoid generating derivations with names
@@ -56,7 +59,13 @@ let
         timeout-up
         timeout-down
         restart-on-upgrade
-        ;
+      ;
+      propertiesText =
+        let a = mapAttrsRecursive
+          (path: value: "writepath ${concatStringsSep "/" path} ${builtins.toString value}\n")
+          properties;
+        in collect builtins.isString a;
+
       buildInputs =
         buildInputs ++ dependencies ++ contents ++ lib.optional (controller != null) controller;
       inherit controller dependencies contents;