Source file types.ml

type span = int64
(** A span identifier.

    The meaning of the identifier depends on the collector. *)

type trace_id = string
(** A bytestring representing a (possibly distributed) trace made of async
    spans. With opentelemetry this is 16 bytes.
    @since 0.10 *)

type user_data =
  [ `Int of int
  | `String of string
  | `Bool of bool
  | `Float of float
  | `None
  ]
(** User defined data, generally passed as key/value pairs to whatever collector
    is installed (if any). *)

type explicit_span_ctx = {
  span: span;  (** The current span *)
  trace_id: trace_id;  (** The trace this belongs to *)
}
(** A context, passed around for async traces.
    @since 0.10 *)

type explicit_span = {
  span: span;
      (** Identifier for this span. Several explicit spans might share the same
          identifier since we can differentiate between them via [meta]. *)
  trace_id: trace_id;  (** The trace this belongs to *)
  mutable meta: Meta_map.t;
      (** Metadata for this span (and its context). This can be used by
          collectors to carry collector-specific information from the beginning
          of the span, to the end of the span. *)
}
(** Explicit span, with collector-specific metadata. This is richer than
    {!explicit_span_ctx} but not intended to be passed around (or sent across
    the wire), unlike {!explicit_span_ctx}. *)

type extension_event = ..
(** An extension event, used to add features that are backend specific or simply
    not envisioned by [trace].
    @since 0.8 *)