lwt_monitor_info.ml

let lwt_monitor_info =
  let open Lwt in
  let started = ref false in
  let previous = ref (None : float option) in
  let reads = ref [] in
  fun () ->
    begin match !started with
    | false ->
      Lwt.ignore_result begin
        let rec loop () =
          let time = Time.(now () |> to_float) in
          begin match !previous with
          | None -> previous := Some time
          | Some p ->
            (* if time -. p > !maximum then maximum := time -. p else (); *)
            reads := (time, time -. p) :: !reads;
            if List.length !reads > 10 then (
              reads := List.sort 
                  ~cmp:(fun a b -> Float.compare (snd b) (snd a)) !reads 
                       |> (fun l -> List.take l 10);
            );
            previous := Some time;
          end;
          Lwt_main.yield () >>= fun () ->
          loop ()
        in
        loop ()
      end;
      started := true;
    | true -> ();
    end;
    let open Html5 in
    div [
      pcdataf "Maximal unavailability:";
      ul (List.map !reads ~f:(fun (date, delay) ->
          li [pcdataf "%s (%.3f): %f" 
                Time.(of_float date |> to_string) date delay]));
      pcdataf "Features:";
      ul (List.map features ~f:(fun f ->
          li [pcdataf "%s: %b" (feature_to_string f) (Lwt_sys.have f)]));
    ]