Add Upstart job for PulseAudio as a system-wide daemon.

svn path=/nixos/trunk/; revision=13907

system/ids.nix

@@ -19,6 +19,7 @@
     dovecot = 15;
     tomcat = 16;
     gnunetd = 17;
+    pulseaudio = 22; # must match `pulseaudio' GID
 
     nixbld = 30000; # start of range of uids
     nobody = 65534;
@@ -45,6 +46,7 @@
     uucp = 19;
     lp = 20;
     tomcat = 21;
+    pulseaudio = 22; # must match `pulseaudio' UID
     
     users = 100;
     nixbld = 30000;

system/options.nix

@@ -3066,5 +3066,6 @@ root        ALL=(ALL) SETENV: ALL
     (import ../upstart-jobs/manual.nix)
     (import ../upstart-jobs/rogue.nix)
     (import ../upstart-jobs/guest-users.nix)
+    (import ../upstart-jobs/pulseaudio.nix)
   ];
 }

upstart-jobs/pulseaudio.nix

@@ -0,0 +1,94 @@
+{pkgs, config, ...}:
+
+###### interface
+let
+  inherit (pkgs.lib) mkOption;
+
+  uid = (import ../system/ids.nix).uids.pulseaudio;
+  gid = (import ../system/ids.nix).gids.pulseaudio;
+
+  options = {
+    services = {
+      pulseaudio = {
+        enable = mkOption {
+          default = false;
+          description = ''
+            Whether to enable the PulseAudio system-wide audio server.
+            Note that the documentation recommends running PulseAudio
+            daemons per-user rather than system-wide on desktop machines.
+          '';
+        };
+
+        logLevel = mkOption {
+          default = "notice";
+          example = "debug";
+          description = ''
+            A string denoting the log level: one of
+            <literal>error</literal>, <literal>warn</literal>,
+            <literal>notice</literal>, <literal>info</literal>,
+            or <literal>debug</literal>.
+          '';
+        };
+      };
+    };
+  };
+in
+
+###### implementation
+
+# For some reason, PulseAudio wants UID == GID.
+assert uid == gid;
+
+{
+  require = [
+    options
+  ];
+
+  environment = {
+
+    extraPackages =
+      pkgs.lib.optional
+        (!config.environment.cleanStart)
+        pkgs.pulseaudio;
+  };
+
+  users = {
+    extraUsers = [
+      { name = "pulse";
+        inherit uid;
+        group = "pulse";
+        description = "PulseAudio system-wide daemon";
+        home = "/var/run/pulse";
+      }
+    ];
+
+    extraGroups = [
+      { name = "pulse";
+        inherit gid;
+      }
+    ];
+  };
+
+  services = {
+    extraJobs = [{
+      name = "pulseaudio";
+
+      job = ''
+        description "PulseAudio system-wide server"
+
+        start on startup
+        stop on shutdown
+
+        start script
+          test -d /var/run/pulse ||			\
+          ( mkdir -p --mode 755 /var/run/pulse &&	\
+            chown pulse:pulse /var/run/pulse )
+        end script
+
+        respawn ${pkgs.pulseaudio}/bin/pulseaudio               \
+          --system --daemonize                                  \
+          --log-level="${config.services.pulseaudio.logLevel}"
+      '';
+    }];
+  };
+}