Allow configuring thermal zone shown in polybar

This is highly likely to be different on different machines.

3 files changed, 11 insertions, 5 deletions

diff --git a/tw/home/cern.scm b/tw/home/cern.scm
index a653bde7..842b8658 100644
--- a/tw/home/cern.scm
+++ b/tw/home/cern.scm
@@ -58,6 +58,7 @@
         (bluetooth? #t)
         (battery-name "BAT0")
         (ac-adapter-name "AC")
+        (thermal-zone "0")
         (monitors
          (list (home-monitor-configuration
                 (name "eDP-1")
diff --git a/tw/services/desktop.scm b/tw/services/desktop.scm
index 53385761..1aa2bb2d 100644
--- a/tw/services/desktop.scm
+++ b/tw/services/desktop.scm
@@ -103,6 +103,11 @@ true, configure the user interface to use it.")
 See @code{/sys/class/power_supply}.")
   (ac-adapter-name maybe-string "The device name of the system's mains power
 supply, if any.  See @code{/sys/class/power_supply}.")
+  ;; The default mirrors the previously hard-coded value from polybar.ini, for
+  ;; compatibility.  It is probably not a great default; "0" might be better.
+  (thermal-zone (string "1") "The number of the thermal sensor used to show
+the system temperature.  Run @code{grep '^' /sys/class/thermal/thermal_zone*/type}
+to list zones and their types.")
   (monitors list-of-monitors "List of monitor declarations to apply."))
 
 (define polybar-wrapper
@@ -124,7 +129,7 @@ supply, if any.  See @code{/sys/class/power_supply}.")
           (when monitor-connected?
             (execl #$(file-append polybar "/bin/polybar") "polybar"))))))
 
-(define (polybar-service monitor battery-name ac-adapter-name)
+(define (polybar-service monitor battery-name ac-adapter-name thermal-zone)
   (shepherd-service
    (documentation (string-append "Polybar desktop bar for monitor " monitor "."))
    (provision (list (symbol-append 'polybar- (string->symbol monitor))))
@@ -135,6 +140,7 @@ supply, if any.  See @code{/sys/class/power_supply}.")
              (cons* #$(string-append "POLYBAR_MONITOR=" monitor)
                     #$(string-append "POLYBAR_BATTERY=" (maybe-value battery-name ""))
                     #$(string-append "POLYBAR_AC_ADAPTER=" (maybe-value ac-adapter-name ""))
+                    #$(string-append "POLYBAR_THERMAL_ZONE=" thermal-zone)
                     (default-environment-variables))))
    (stop #~(make-kill-destructor))))
 
@@ -329,7 +335,7 @@ show_border=1
 (define (home-shepherd-services config)
   "Run various daemons in my user profile."
   (match-record config <home-desktop-configuration>
-                (nvidia-driver? bluetooth? desktop-background battery-name ac-adapter-name monitors)
+                (nvidia-driver? bluetooth? desktop-background battery-name ac-adapter-name thermal-zone monitors)
     `(,(shepherd-service
         (documentation "NetworkManager applet; provides a GUI for network connections.")
         (provision '(nm-applet))
@@ -424,7 +430,7 @@ show_border=1
                    (stop #~(make-kill-destructor))))
             '())
 
-      ,@(map (compose (cut polybar-service <> battery-name ac-adapter-name)
+      ,@(map (compose (cut polybar-service <> battery-name ac-adapter-name thermal-zone)
                       home-monitor-configuration-name)
              monitors))))
 
diff --git a/tw/services/files/polybar.ini b/tw/services/files/polybar.ini
index 54f6ff19..5c398c4a 100644
--- a/tw/services/files/polybar.ini
+++ b/tw/services/files/polybar.ini
@@ -153,8 +153,7 @@ ramp-coreload-7-foreground = ${colors.alert}
 
 [module/temp]
 type = internal/temperature
-; head /sys/class/thermal/thermal_zone*/type
-thermal-zone = 1
+thermal-zone = ${env:POLYBAR_THERMAL_ZONE}
 format-prefix = "🌡 "
 format-prefix-foreground = ${colors.primary}
 format-warn-prefix = "🌡 "