Improve yt-dlp service

- allow configuring odd or even days (useful for future get-iplayer
  service so they run on alternating days)
- auto-update yt-dlp if not using the system package

1 files changed, 8 insertions, 4 deletions

diff --git a/tw/services/media.scm b/tw/services/media.scm
index 4bff1818..5fd5b2b5 100644
--- a/tw/services/media.scm
+++ b/tw/services/media.scm
@@ -15,10 +15,10 @@
 (define (string-or-gexp? value)
   (or (string? value) (gexp? value)))
 
-(define random-time-every-second-night
+(define (random-time-every-second-night day-predicate)
   #~(lambda (now)
       (let* ((even-day
-              (if (even? (tm:yday (localtime now)))
+              (if (#$day-predicate (tm:yday (localtime now)))
                   now
                   (next-day-from now)))
              (deterministic-value
@@ -30,13 +30,15 @@
          (next-hour-from even-day (list (1+ (string-hash deterministic-value 6))))
          (list (string-hash deterministic-value 60))))))
 
+
+
 (define-configuration/no-serialization yt-dlp-configuration
   (media-directory string "The directory in which to store downloaded media.
 The service expects a @code{.yt-dlp} config directory inside this one.")
   (yt-dlp (package-or-false yt-dlp) "The yt-dlp package to use; or
 @code{#false} to use the yt-dlp script inside the config directory.")
-  (schedule (string-or-gexp random-hour-every-second-night) "The mcron
-schedule on which to run the download script.  By default, picks a random hour
+  (schedule (string-or-gexp (random-time-every-second-night 'even?)) "The mcron
+schedule on which to run the download script.  By default, picks a random time
 between 01:00 and 06:00 every second night.")
   (user (string "root") "The Unix user name to run the script as.")
   (group (string "root") "The Unix group name to run the script as."))
@@ -55,6 +57,8 @@ between 01:00 and 06:00 every second night.")
               ;; `setgid' first while we're still root
               (setgid (group:gid (getgr #$(yt-dlp-configuration-group config))))
               (setuid (passwd:uid (getpw #$(yt-dlp-configuration-user config))))
+              #$@(if yt-dlp-package '()
+                     (list #~(system* #$yt-dlp-executable "--ignore-config" "--update")))
               (execl #$yt-dlp-executable
                      "yt-dlp" "--ignore-config" "--config-location" ".yt-dlp"))
             ;; Human-readable string for `herd schedule mcron'.