add Systemd_main

bin/dune

@@ -2,4 +2,4 @@
  (public_name ocaml-systemd)
  (name main)
  (modes byte exe)
- (libraries systemd systemd.xlog eio_main fmt xlog))
+ (libraries systemd systemd.xlog systemd.main eio_main fmt xlog))

bin/main.ml

@@ -2,23 +2,16 @@ include (val Xlog.logs __FUNCTION__)
 
 open Eio.Std
 
-let () = Eio_main.run @@ fun env ->
+let () = Systemd_main.run ~min_level:Xlog.DEBUG ~ready_status:(Some "meow meow") ~shutdown:(fun env _ctx -> Eio.Time.sleep env#clock 10.0) @@ fun env notify ->
   let clock = Eio.Stdenv.clock env in
-  Switch.run ~name:"main" @@ fun sw ->
+  Switch.run @@ fun sw ->
-    if Systemd.is_journald_attached () then
-      Xlog.add_writer (Systemd_xlog.make_writer ~sw ~env) ~min_level:Xlog.DEBUG
-    else
-      Xlog.init_pretty_writer stdout ~min_level:Xlog.DEBUG;
-
     info (fun m -> m "meow meow meow");
 
     let fds = Systemd.Fdstore.listen_fds ~sw in
     List.iter (fun (name, fd) -> Stdlib.Format.printf "got fd %a=%a\n%!" (Fmt.option ~none:(Fmt.any "<none>") Fmt.string) name Eio_unix.Fd.pp fd; Eio_linux.Low_level.writev fd [Cstruct.of_string "meow"]) fds;
 
-    let ctx = Systemd.Notify.make ~sw ~env in
-    info (fun m -> m "notifying!");
-    Systemd.Notify.ready ctx;
     info (fun m -> m "performing barrier");
-    Systemd.Notify.barrier ctx;
+    Systemd.Notify.barrier notify;
     info (fun m -> m "done");
-    Eio.Time.sleep clock 2.0
+    Eio.Time.sleep clock 10.0;
+    info (fun m -> m "done 2")

lib_main/dune

@@ -0,0 +1,5 @@
+(library
+  (name systemd_main)
+  (public_name systemd.main)
+  (preprocess (pps ppx_unicode))
+  (libraries eio eio_linux systemd systemd.xlog xlog))

lib_main/systemd_main.ml

@@ -0,0 +1,45 @@
+let noop _env _ctx = ()
+
+let run ?(min_level=Xlog.WARN) ?(init=noop) ?(ready_status=None) ?(reload=noop) ?(shutdown=noop) func =
+  Eio_linux.run @@ fun env ->
+    Eio.Switch.run ~name:"main" @@ fun sw ->
+      if Systemd.is_journald_attached () then
+        Xlog.add_writer (Systemd_xlog.make_writer ~sw ~env) ~min_level
+      else
+        Xlog.init_pretty_writer stdout ~min_level;
+
+      let ctx = Systemd.Notify.make ~sw ~env in
+
+      let stop_cond = Eio.Condition.create () in
+      let reload_cond = Eio.Condition.create () in
+
+      let handle_stop _ =
+        Eio.Condition.broadcast stop_cond
+      in
+      let handle_reload _ =
+        Eio.Condition.broadcast reload_cond
+      in
+      Sys.set_signal Sys.sigint (Signal_handle handle_stop);
+      Sys.set_signal Sys.sigterm (Signal_handle handle_stop);
+      Sys.set_signal Sys.sighup (Signal_handle handle_reload);
+
+      init env ctx;
+
+      let rec reload_loop () =
+        Eio.Condition.await_no_mutex reload_cond;
+        Systemd.Notify.reloading ctx;
+        reload env ctx;
+        Systemd.Notify.ready ~status:ready_status ctx;
+        reload_loop ()
+      in
+
+      Eio.Switch.on_release sw (fun () ->
+        Systemd.Notify.stopping ctx;
+        shutdown env ctx);
+
+      Systemd.Notify.ready ~status:ready_status ctx;
+
+      Eio.Fiber.any
+        [(fun () -> Eio.Condition.await_no_mutex stop_cond);
+         reload_loop;
+         (fun () -> func env ctx)];