feat(cohttp): trace post_form

src/integrations/cohttp/opentelemetry_cohttp_lwt.ml

@@ -147,8 +147,7 @@ end = struct
 end
 
 let client ?(scope : Otel.Trace.scope option) (module C : Cohttp_lwt.S.Client)  =
-  let module Traced : Cohttp_lwt.S.Client = struct
-      include C
+  let module Traced = struct
       open Lwt.Syntax
 
       let attrs_for ~uri ~meth () =
@@ -168,6 +167,8 @@ let client ?(scope : Otel.Trace.scope option) (module C : Cohttp_lwt.S.Client)
         Header.add headers Traceparent.name
           (Traceparent.to_value ~trace_id:scope.trace_id ~parent_id:scope.span_id ())
 
+      type ctx = C.ctx
+
       let call ?ctx ?headers ?body ?chunked meth (uri : Uri.t) : (Response.t * Cohttp_lwt.Body.t) Lwt.t =
         let (trace_id, parent, attrs) = context_for ~uri ~meth in
         Otel_lwt.Trace.with_ "request"
@@ -200,6 +201,27 @@ let client ?(scope : Otel.Trace.scope option) (module C : Cohttp_lwt.S.Client)
         call ?ctx ?headers ?body ?chunked `PUT uri
 
       let patch ?ctx ?body ?chunked ?headers uri =
-        call ?ctx ?headers ?body ?chunked `PATCH uri    end
+        call ?ctx ?headers ?body ?chunked `PATCH uri
+
+      let post_form ?ctx ?headers ~params uri =
+        let (trace_id, parent, attrs) = context_for ~uri ~meth:`POST in
+        Otel_lwt.Trace.with_ "request"
+          ~kind:Span_kind_client
+          ?trace_id
+          ?parent
+          ~attrs
+          (fun scope ->
+            let headers = add_traceparent scope headers in
+            let* (res, body) =
+              C.post_form ?ctx ~headers ~params uri
+            in
+            Otel.Trace.add_attrs scope (fun () ->
+                let code = Response.status res in
+                let code = Code.code_of_status code in
+                [ ("http.status_code", `Int code) ]) ;
+            Lwt.return (res, body))
+
+      let callv = C.callv (* TODO *)
+    end
   in
   (module Traced : Cohttp_lwt.S.Client)