update the emit test so it records how many bytes were emitted

src/client-ocurl/opentelemetry_client_ocurl.ml

@@ -117,6 +117,8 @@ module Backend_impl : sig
 
   val send_event : t -> Event.t -> unit
 
+  val n_bytes_sent : unit -> int
+
   val shutdown : t -> on_done:(unit -> unit) -> unit
 end = struct
   open Opentelemetry.Proto
@@ -187,6 +189,10 @@ end = struct
 
   let[@inline] send_event (self : t) ev : unit = B_queue.push self.q ev
 
+  let n_bytes_sent_ = Atomic.make 0
+
+  let[@inline] n_bytes_sent () = Atomic.get n_bytes_sent_
+
   (** Thread that, in a loop, reads from [q] to get the next message to send via
       http *)
   let bg_thread_loop (self : t) : unit =
@@ -199,7 +205,9 @@ end = struct
         Self_trace.with_ ~kind:Span_kind_producer name
           ~attrs:[ "n", `Int (List.length l) ]
       in
-      conv l |> send_http_ ~stop ~config ~url client
+      let msg = conv l in
+      ignore (Atomic.fetch_and_add n_bytes_sent_ (String.length msg) : int);
+      send_http_ ~stop ~config ~url client msg
     in
     try
       while not (Atomic.get stop) do
@@ -471,3 +479,5 @@ let with_setup ?stop ?config ?(enable = true) () f =
     Fun.protect ~finally:remove_backend f
   ) else
     f ()
+
+let n_bytes_sent = Backend_impl.n_bytes_sent

src/client-ocurl/opentelemetry_client_ocurl.mli

@@ -11,6 +11,9 @@ val set_headers : (string * string) list -> unit
 module Atomic = Opentelemetry_atomic.Atomic
 module Config = Config
 
+val n_bytes_sent : unit -> int
+(** Global counter of bytes sent (or attempted to be sent) *)
+
 val create_backend :
   ?stop:bool Atomic.t ->
   ?config:Config.t ->

src/client/self_trace.ml

@@ -1,6 +1,6 @@
 module OT = Opentelemetry
 
-let enabled = Atomic.make true
+let enabled = Atomic.make false
 
 let add_event (scope : OT.Scope.t) ev = OT.Scope.add_event scope (fun () -> ev)
 

tests/bin/emit1.ml

@@ -86,6 +86,8 @@ let run () =
         [
           sum ~name:"num-sleep" ~is_monotonic:true
             [ int (Atomic.get num_sleep) ];
+          sum ~name:"otel.bytes-sent" ~is_monotonic:true ~unit_:"B"
+            [ int (Opentelemetry_client_ocurl.n_bytes_sent ()) ];
         ]);
 
   let n_jobs = max 1 !n_jobs in