new package watch-outputs and example of its use

2024-08-14 22:58:17 +01:00
parent 2f82e0dab8
commit d79a941504
17 changed files with 172 additions and 0 deletions
--- a/pkgs/watch-outputs/watch-outputs.fnl
+++ b/pkgs/watch-outputs/watch-outputs.fnl
@@ -0,0 +1,63 @@
+(local { : system : assoc : split : table= } (require :anoia))
+(local svc (require :anoia.svc))
+(local { : view } (require :fennel))
+(local { : kill } (require :lualinux))
+
+(fn split-paths [paths]
+  (icollect [_ path (ipairs paths)]
+    (split "/" path)))
+
+(fn parse-args [args]
+  (match args
+    ["-r" service & rest] (assoc (parse-args rest)
+                                 :controlled-service service
+                                 :action :restart)
+    ["-R" service & rest] (assoc (parse-args rest)
+                                 :controlled-service service
+                                 :action :restart-all)
+    ["-s" signal service & rest] (assoc (parse-args rest)
+                                        :controlled-service service
+                                        :action [:signal signal])
+    [watched-service & paths] { : watched-service
+                                :paths (split-paths paths)
+                                }))
+
+(fn dig [tree path]
+  (match path
+    [el & more] (dig (. tree el) more)
+    [el] (. tree el)
+    [] tree))
+
+(fn changed? [paths old-tree new-tree]
+  (accumulate [changed? false
+               _ path (ipairs paths)]
+    (or changed? (not (table= (dig old-tree path) (dig new-tree path))))))
+
+
+(fn do-action [action service]
+  (case action
+    :restart (system "s6-svc -r /run/service/%s" service)
+    :restart-all (system "s6-rc -b -d %q; s6-rc-up-tree %q" service service)
+    [:signal n] (system "s6-svc -s %d /run/service/%s" n service)))
+
+(fn run []
+  (let [{
+         : controlled-service
+         : action
+         : watched-service
+         : paths } (parse-args arg)
+        dir (.. watched-service "/.outputs")
+        _ (print :service-dir dir)
+        service (assert (svc.open dir))]
+    (print "watching " watched-service)
+    (accumulate [tree (service:output ".")
+                 v (service:events)]
+      (let [new-tree (service:output ".")]
+        (print :was (view tree) :now (view new-tree))
+        (when (changed? paths tree new-tree)
+          (print "watched path event:"  action controlled-service)
+          (do-action action controlled-service))
+        new-tree))))
+
+
+{ : run }