From c66623d0a7571978b290934739d50ae4e8c6bb18 Mon Sep 17 00:00:00 2001
From: Pietro Abate <pietro.abate@tezcore.com>
Date: Tue, 27 Nov 2018 16:07:23 +0100
Subject: [PATCH] Worker: register Closed error globally

---
 src/lib_shell/block_validator.ml  |  1 -
 src/lib_shell/block_validator.mli |  2 --
 src/lib_shell/worker.ml           | 56 ++++++++++++++++++-------------
 src/lib_shell/worker.mli          |  9 ++---
 4 files changed, 37 insertions(+), 31 deletions(-)

diff --git a/src/lib_shell/block_validator.ml b/src/lib_shell/block_validator.ml
index c3e0a497d..98cb7b06b 100644
--- a/src/lib_shell/block_validator.ml
+++ b/src/lib_shell/block_validator.ml
@@ -75,7 +75,6 @@ end
 module Worker = Worker.Make (Name) (Event) (Request) (Types)
 
 type t = Worker.infinite Worker.queue Worker.t
-type error += Closed = Worker.Closed
 
 let debug w =
   Format.kasprintf (fun msg -> Worker.record_event w (Debug msg))
diff --git a/src/lib_shell/block_validator.mli b/src/lib_shell/block_validator.mli
index 3184a0845..88d231680 100644
--- a/src/lib_shell/block_validator.mli
+++ b/src/lib_shell/block_validator.mli
@@ -34,8 +34,6 @@ type limits = {
 type validator_kind =
   | Internal of Context.index
 
-type error += Closed of unit
-
 val create:
   limits ->  Distributed_db.t -> validator_kind ->
   t tzresult Lwt.t
diff --git a/src/lib_shell/worker.ml b/src/lib_shell/worker.ml
index 1c41211ae..344e9563e 100644
--- a/src/lib_shell/worker.ml
+++ b/src/lib_shell/worker.ml
@@ -58,6 +58,33 @@ module type TYPES = sig
   val pp : Format.formatter -> view -> unit
 end
 
+(** An error returned when trying to communicate with a worker that
+    has been closed.*)
+type worker_name = {base: string; name:string}
+type Error_monad.error += Closed of worker_name
+
+let () =
+  register_error_kind `Permanent
+    ~id:("worker.closed")
+    ~title:("Worker closed")
+    ~description:
+      ("An operation on a worker could not complete \
+        before it was shut down.")
+    ~pp: (fun ppf w ->
+        Format.fprintf ppf
+          "Worker %s[%s] has been shut down."
+          w.base w.name)
+    Data_encoding.(
+      conv
+        (fun { base ; name } -> (base,name))
+        (fun (name,base) -> { base ; name })
+        (obj1
+           (req "worker" (tup2 string string))
+        )
+    )
+    (function Closed w -> Some w | _ -> None)
+    (fun w -> Closed w)
+
 module type T = sig
 
   module Name: NAME
@@ -92,10 +119,6 @@ module type T = sig
   (** Create a table of workers. *)
   val create_table : 'kind buffer_kind -> 'kind table
 
-  (** An error returned when trying to communicate with a worker that
-      has been closed. *)
-  type Error_monad.error += Closed of Name.t
-
   (** The callback handlers specific to each worker instance. *)
   module type HANDLERS = sig
 
@@ -284,24 +307,6 @@ module Make
     zombies : (int, 'kind t) Hashtbl.t
   }
 
-  type error += Closed of Name.t
-
-  let () =
-    register_error_kind `Permanent
-      ~id:("worker." ^ base_name ^ ".closed")
-      ~title:("Worker " ^ base_name ^ " closed")
-      ~description:
-        ("An operation on a " ^ base_name ^
-         " worker could not complete \
-          before it was shut down.")
-      ~pp: (fun ppf name ->
-          Format.fprintf ppf
-            "Worker %s[%a] has been shut down."
-            base_name Name.pp name)
-      Data_encoding.(obj1 (req "worker_id" Name.encoding))
-      (function Closed chain_id -> Some chain_id | _ -> None)
-      (fun chain_id -> Closed chain_id)
-
   let queue_item ?u r =
     Time.now (),
     Message (r, u)
@@ -348,13 +353,16 @@ module Make
          Lwt_pipe.push message_queue (queue_item ~u request) >>= fun () ->
          t)
       (function
-        | Lwt_pipe.Closed -> fail (Closed w.name)
+        | Lwt_pipe.Closed ->
+            let name = Format.asprintf "%a" Name.pp w.name in
+            fail (Closed {base=base_name; name})
         | exn -> fail (Exn exn))
 
   let close (type a) (w : a t) =
     let wakeup = function
       | _, Message (_, Some u) ->
-          Lwt.wakeup_later u (Error [ Closed w.name ])
+          let name = Format.asprintf "%a" Name.pp w.name in
+          Lwt.wakeup_later u (Error [ Closed {base=base_name; name} ])
       | _ -> () in
     let close_queue message_queue =
       let messages = Lwt_pipe.pop_all_now message_queue in
diff --git a/src/lib_shell/worker.mli b/src/lib_shell/worker.mli
index b03606938..54288e623 100644
--- a/src/lib_shell/worker.mli
+++ b/src/lib_shell/worker.mli
@@ -119,6 +119,11 @@ end
 
 (** {2 Worker group maker} *)
 
+(** An error returned when trying to communicate with a worker that
+    has been closed. *)
+type worker_name = {base: string; name:string}
+type Error_monad.error += Closed of worker_name
+
 (** Functor to build a group of workers.
     At that point, all the types are fixed and introspectable,
     but the actual parameters and event handlers can be tweaked
@@ -157,10 +162,6 @@ module type T = sig
   (** Create a table of workers. *)
   val create_table : 'kind buffer_kind -> 'kind table
 
-  (** An error returned when trying to communicate with a worker that
-      has been closed. *)
-  type Error_monad.error += Closed of Name.t
-
   (** The callback handlers specific to each worker instance. *)
   module type HANDLERS = sig