nixos/pipewire: Use formats.json, stricter typing, line breaks

The upstream pipewire config is written in an almost, but not quite
JSON format. The parser accepts standard JSON, though, so we don't
need to write our file in the same nonstandard version.

The typing for all config options is changed from `types.attrs`, which
behaves poorly when the option is set from multiple locations, to the
formats.json-type.

Also, rewrite some very long one-liners for improved readability.

2 files changed, 66 insertions, 57 deletions

diff --git a/nixos/modules/services/desktops/pipewire/pipewire-media-session.nix b/nixos/modules/services/desktops/pipewire/pipewire-media-session.nix
index 539a4cf4469..17a2d49bb1f 100644
--- a/nixos/modules/services/desktops/pipewire/pipewire-media-session.nix
+++ b/nixos/modules/services/desktops/pipewire/pipewire-media-session.nix
@@ -4,6 +4,7 @@
 with lib;
 
 let
+  json = pkgs.formats.json {};
   cfg = config.services.pipewire.media-session;
   enable32BitAlsaPlugins = cfg.alsa.support32Bit
                            && pkgs.stdenv.isx86_64
@@ -17,24 +18,13 @@ let
     media-session = (builtins.fromJSON (builtins.readFile ./media-session.conf.json));
     v4l2-monitor = (builtins.fromJSON (builtins.readFile ./v4l2-monitor.conf.json));
   };
-  # Helpers for generating the pipewire JSON config file
-  mkSPAValueString = v:
-  if builtins.isList v then "[${lib.concatMapStringsSep " " mkSPAValueString v}]"
-  else if lib.types.attrs.check v then
-    "{${lib.concatStringsSep " " (mkSPAKeyValue v)}}"
-  else if builtins.isString v then "\"${lib.generators.mkValueStringDefault { } v}\""
-  else lib.generators.mkValueStringDefault { } v;
-
-  mkSPAKeyValue = attrs: map (def: def.content) (
-  lib.sortProperties
-    (
-      lib.mapAttrsToList
-        (k: v: lib.mkOrder (v._priority or 1000) "${lib.escape [ "=" ":" ] k} = ${mkSPAValueString (v._content or v)}")
-        attrs
-    )
-  );
-
-  toSPAJSON = attrs: lib.concatStringsSep "\n" (mkSPAKeyValue attrs);
+
+  configs = {
+    alsa-monitor = recursiveUpdate defaults.alsa-monitor cfg.config.alsa-monitor;
+    bluez-monitor = recursiveUpdate defaults.bluez-monitor cfg.config.bluez-monitor;
+    media-session = recursiveUpdate defaults.media-session cfg.config.media-session;
+    v4l2-monitor = recursiveUpdate defaults.v4l2-monitor cfg.config.v4l2-monitor;
+  };
 in {
 
   meta = {
@@ -62,7 +52,7 @@ in {
 
       config = {
         media-session = mkOption {
-          type = types.attrs;
+          type = json.type;
           description = ''
             Configuration for the media session core. For details see
             https://gitlab.freedesktop.org/pipewire/pipewire/-/blob/${cfg.package.version}/src/daemon/media-session.d/media-session.conf
@@ -71,7 +61,7 @@ in {
         };
 
         alsa-monitor = mkOption {
-          type = types.attrs;
+          type = json.type;
           description = ''
             Configuration for the alsa monitor. For details see
             https://gitlab.freedesktop.org/pipewire/pipewire/-/blob/${cfg.package.version}/src/daemon/media-session.d/alsa-monitor.conf
@@ -80,7 +70,7 @@ in {
         };
 
         bluez-monitor = mkOption {
-          type = types.attrs;
+          type = json.type;
           description = ''
             Configuration for the bluez5 monitor. For details see
             https://gitlab.freedesktop.org/pipewire/pipewire/-/blob/${cfg.package.version}/src/daemon/media-session.d/bluez-monitor.conf
@@ -89,7 +79,7 @@ in {
         };
 
         v4l2-monitor = mkOption {
-          type = types.attrs;
+          type = json.type;
           description = ''
             Configuration for the V4L2 monitor. For details see
             https://gitlab.freedesktop.org/pipewire/pipewire/-/blob/${cfg.package.version}/src/daemon/media-session.d/v4l2-monitor.conf
@@ -106,15 +96,34 @@ in {
     systemd.packages = [ cfg.package ];
     systemd.user.services.pipewire-media-session.wantedBy = [ "pipewire.service" ];
 
-    environment.etc."pipewire/media-session.d/media-session.conf" = { text = toSPAJSON (recursiveUpdate defaults.media-session cfg.config.media-session); };
-    environment.etc."pipewire/media-session.d/v4l2-monitor.conf" = { text = toSPAJSON (recursiveUpdate defaults.v4l2-monitor cfg.config.v4l2-monitor); };
+    environment.etc."pipewire/media-session.d/media-session.conf" = {
+      source = json.generate "media-session.conf" configs.media-session;
+    };
+    environment.etc."pipewire/media-session.d/v4l2-monitor.conf" = {
+      source = json.generate "v4l2-monitor.conf" configs.v4l2-monitor;
+    };
 
-    environment.etc."pipewire/media-session.d/with-alsa" = mkIf config.services.pipewire.alsa.enable { text = ""; };
-    environment.etc."pipewire/media-session.d/alsa-monitor.conf" = mkIf config.services.pipewire.alsa.enable { text = toSPAJSON (recursiveUpdate defaults.alsa-monitor cfg.config.alsa-monitor); };
+    environment.etc."pipewire/media-session.d/with-alsa" =
+      mkIf config.services.pipewire.alsa.enable {
+        text = "";
+      };
+    environment.etc."pipewire/media-session.d/alsa-monitor.conf" =
+      mkIf config.services.pipewire.alsa.enable {
+        source = json.generate "alsa-monitor.conf" configs.alsa-monitor;
+      };
 
-    environment.etc."pipewire/media-session.d/with-pulseaudio" = mkIf config.services.pipewire.pulse.enable { text = ""; };
-    environment.etc."pipewire/media-session.d/bluez-monitor.conf" = mkIf config.services.pipewire.pulse.enable { text = toSPAJSON (recursiveUpdate defaults.bluez-monitor cfg.config.bluez-monitor); };
+    environment.etc."pipewire/media-session.d/with-pulseaudio" =
+      mkIf config.services.pipewire.pulse.enable {
+        text = "";
+      };
+    environment.etc."pipewire/media-session.d/bluez-monitor.conf" =
+      mkIf config.services.pipewire.pulse.enable {
+        source = json.generate "bluez-monitor.conf" configs.bluez-monitor;
+      };
 
-    environment.etc."pipewire/media-session.d/with-jack" = mkIf config.services.pipewire.jack.enable { text = ""; };
+    environment.etc."pipewire/media-session.d/with-jack" =
+      mkIf config.services.pipewire.jack.enable {
+        text = "";
+      };
   };
 }
diff --git a/nixos/modules/services/desktops/pipewire/pipewire.nix b/nixos/modules/services/desktops/pipewire/pipewire.nix
index 7cf19706a63..dbd6c5d87e1 100644
--- a/nixos/modules/services/desktops/pipewire/pipewire.nix
+++ b/nixos/modules/services/desktops/pipewire/pipewire.nix
@@ -4,6 +4,7 @@
 with lib;
 
 let
+  json = pkgs.formats.json {};
   cfg = config.services.pipewire;
   enable32BitAlsaPlugins = cfg.alsa.support32Bit
                            && pkgs.stdenv.isx86_64
@@ -29,24 +30,13 @@ let
     pipewire-pulse = builtins.fromJSON (builtins.readFile ./pipewire-pulse.conf.json);
   };
 
-  # Helpers for generating the pipewire JSON config file
-  mkSPAValueString = v:
-  if builtins.isList v then "[${lib.concatMapStringsSep " " mkSPAValueString v}]"
-  else if lib.types.attrs.check v then
-    "{${lib.concatStringsSep " " (mkSPAKeyValue v)}}"
-  else if builtins.isString v then "\"${lib.generators.mkValueStringDefault { } v}\""
-  else lib.generators.mkValueStringDefault { } v;
-
-  mkSPAKeyValue = attrs: map (def: def.content) (
-  lib.sortProperties
-    (
-      lib.mapAttrsToList
-        (k: v: lib.mkOrder (v._priority or 1000) "${lib.escape [ "=" ] k} = ${mkSPAValueString (v._content or v)}")
-        attrs
-    )
-  );
-
-  toSPAJSON = attrs: lib.concatStringsSep "\n" (mkSPAKeyValue attrs);
+  configs = {
+    client = recursiveUpdate defaults.client cfg.config.client;
+    client-rt = recursiveUpdate defaults.client-rt cfg.config.client-rt;
+    jack = recursiveUpdate defaults.jack cfg.config.jack;
+    pipewire = recursiveUpdate defaults.pipewire cfg.config.pipewire;
+    pipewire-pulse = recursiveUpdate defaults.pipewire-pulse cfg.config.pipewire-pulse;
+  };
 in {
 
   meta = {
@@ -78,7 +68,7 @@ in {
 
       config = {
         client = mkOption {
-          type = types.attrs;
+          type = json.type;
           default = {};
           description = ''
             Configuration for pipewire clients. For details see
@@ -87,7 +77,7 @@ in {
         };
 
         client-rt = mkOption {
-          type = types.attrs;
+          type = json.type;
           default = {};
           description = ''
             Configuration for realtime pipewire clients. For details see
@@ -96,7 +86,7 @@ in {
         };
 
         jack = mkOption {
-          type = types.attrs;
+          type = json.type;
           default = {};
           description = ''
             Configuration for the pipewire daemon's jack module. For details see
@@ -105,7 +95,7 @@ in {
         };
 
         pipewire = mkOption {
-          type = types.attrs;
+          type = json.type;
           default = {};
           description = ''
             Configuration for the pipewire daemon. For details see
@@ -114,7 +104,7 @@ in {
         };
 
         pipewire-pulse = mkOption {
-          type = types.attrs;
+          type = json.type;
           default = {};
           description = ''
             Configuration for the pipewire-pulse daemon. For details see
@@ -187,11 +177,21 @@ in {
       source = "${cfg.package}/share/alsa/alsa.conf.d/99-pipewire-default.conf";
     };
 
-    environment.etc."pipewire/client.conf" = { text = toSPAJSON (recursiveUpdate defaults.client cfg.config.client); };
-    environment.etc."pipewire/client-rt.conf" = { text = toSPAJSON (recursiveUpdate defaults.client-rt cfg.config.client-rt); };
-    environment.etc."pipewire/jack.conf" = { text = toSPAJSON (recursiveUpdate defaults.jack cfg.config.jack); };
-    environment.etc."pipewire/pipewire.conf" = { text = toSPAJSON (recursiveUpdate defaults.pipewire cfg.config.pipewire); };
-    environment.etc."pipewire/pipewire-pulse.conf" = { text = toSPAJSON (recursiveUpdate defaults.pipewire-pulse cfg.config.pipewire-pulse); };
+    environment.etc."pipewire/client.conf" = {
+      source = json.generate "client.conf" configs.client;
+    };
+    environment.etc."pipewire/client-rt.conf" = {
+      source = json.generate "client-rt.conf" configs.client-rt;
+    };
+    environment.etc."pipewire/jack.conf" = {
+      source = json.generate "jack.conf" configs.jack;
+    };
+    environment.etc."pipewire/pipewire.conf" = {
+      source = json.generate "pipewire.conf" configs.pipewire;
+    };
+    environment.etc."pipewire/pipewire-pulse.conf" = {
+      source = json.generate "pipewire-pulse.conf" configs.pipewire-pulse;
+    };
 
     environment.sessionVariables.LD_LIBRARY_PATH =
       lib.optional cfg.jack.enable "/run/current-system/sw/lib/pipewire";