rename hmap keys with more consistent scheme

src/core/span.ml

@@ -144,4 +144,4 @@ let set_status = span_set_status
 
 let set_kind = span_set_kind
 
-let k_context : t Context.key = Context.new_key ()
+let k_ambient : t Context.key = Context.new_key ()

src/core/span.mli

@@ -124,4 +124,6 @@ val default_kind : Span_kind.t ref
     set to "internal", following directions from the [.proto] file. It can be
     convenient to set "client" or "server" uniformly in here. *)
 
-val k_context : t Context.key
+val k_ambient : t Context.key
+(** Context key to carry around a {!Span.t} in ambient context.
+    @since NEXT_RELEASE *)

src/core/span_ctx.ml

@@ -88,4 +88,4 @@ let of_w3c_trace_context_exn bs =
   | Ok t -> t
   | Error msg -> invalid_arg @@ spf "invalid w3c trace context: %s" msg
 
-let k_span_ctx : t Hmap.key = Hmap.Key.create ()
+let k_ambient : t Hmap.key = Hmap.Key.create ()

src/core/span_ctx.mli

@@ -36,7 +36,7 @@ val of_w3c_trace_context : bytes -> (t, string) result
 val of_w3c_trace_context_exn : bytes -> t
 (** @raise Invalid_argument if parsing failed *)
 
-val k_span_ctx : t Hmap.key
+val k_ambient : t Hmap.key
 (** Hmap key to carry around a {!Span_ctx.t}, e.g. to remember what the current
     parent span is.
     @since 0.8 *)

src/lib/ambient_span.ml

@@ -1,9 +1,9 @@
 (** Find current span from ambient-context *)
 let[@inline] get () : Span.t option =
-  Opentelemetry_ambient_context.get Span.k_context
+  Opentelemetry_ambient_context.get Span.k_ambient
 
 (** [with_ambient span f] runs [f()] with the current ambient span being set to
     [span] *)
 let[@inline] with_ambient (span : Span.t) (f : unit -> 'a) : 'a =
-  Opentelemetry_ambient_context.with_key_bound_to Span.k_context span (fun _ ->
+  Opentelemetry_ambient_context.with_key_bound_to Span.k_ambient span (fun _ ->
       f ())

src/lib/opentelemetry.ml

@@ -40,7 +40,7 @@ let k_trace_id = Trace_id.k_trace_id
 module Span_id = Span_id
 module Span_ctx = Span_ctx
 
-let k_span_ctx = Span_ctx.k_span_ctx
+let k_ambient = Span_ctx.k_ambient
 
 (** {2 Attributes and conventions} *)
 

src/trace/opentelemetry_trace.ml

@@ -36,9 +36,9 @@ open struct
   (* sanity check: otrace meta-map must be the same as hmap *)
   let () = ignore (fun (k : _ Hmap.key) : _ Ambient_context.Context.key -> k)
 
-  (** Key to access the current span context. *)
+  (** Key to access the current span context. Uses the shared key from core. *)
   let k_span_ctx : OTEL.Span_ctx.t Ambient_context.Context.key =
-    Ambient_context.Context.new_key ()
+    OTEL.Span_ctx.k_ambient
 
   let enter_span (self : state) ~__FUNCTION__ ~__FILE__ ~__LINE__ ~level:_
       ~params:_ ~(data : (_ * Otrace.user_data) list) ~parent name : Otrace.span