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open Common_
external int_of_bool : bool -> int = "%identity"
module Flags = struct
let sampled = 1
let remote = 2
end
type t = {
trace_id: Trace_id.t;
parent_id: Span_id.t;
flags: int;
}
let dummy = { trace_id = Trace_id.dummy; parent_id = Span_id.dummy; flags = 0 }
let make ?(remote = false) ?(sampled = false) ~trace_id ~parent_id () : t =
let flags =
0
lor (int_of_bool remote lsl Flags.remote)
lor (int_of_bool sampled lsl Flags.sampled)
in
{ trace_id; parent_id; flags }
let[@inline] is_valid self =
Trace_id.is_valid self.trace_id && Span_id.is_valid self.parent_id
let[@inline] sampled self = self.flags land (1 lsl Flags.sampled) != 0
let[@inline] is_remote self = self.flags land (1 lsl Flags.remote) != 0
let[@inline] trace_id self = self.trace_id
let[@inline] parent_id self = self.parent_id
let to_w3c_trace_context (self : t) : bytes =
let bs = Bytes.create 55 in
Bytes.set bs 0 '0';
Bytes.set bs 1 '0';
Bytes.set bs 2 '-';
Trace_id.to_hex_into self.trace_id bs 3;
Bytes.set bs (3 + 32) '-';
Span_id.to_hex_into self.parent_id bs 36;
Bytes.set bs 52 '-';
Bytes.set bs 53 '0';
Bytes.set bs 54
(if sampled self then
'1'
else
'0');
bs
let of_w3c_trace_context bs : _ result =
try
if Bytes.length bs <> 55 then invalid_arg "trace context must be 55 bytes";
(match int_of_string_opt (Bytes.sub_string bs 0 2) with
| Some 0 -> ()
| Some n -> invalid_arg @@ spf "version is %d, expected 0" n
| None -> invalid_arg "expected 2-digit version");
if Bytes.get bs 2 <> '-' then invalid_arg "expected '-' before trace_id";
let trace_id =
try Trace_id.of_hex_substring (Bytes.unsafe_to_string bs) 3
with Invalid_argument msg -> invalid_arg (spf "in trace id: %s" msg)
in
if Bytes.get bs (3 + 32) <> '-' then
invalid_arg "expected '-' before parent_id";
let parent_id =
try Span_id.of_hex_substring (Bytes.unsafe_to_string bs) 36
with Invalid_argument msg -> invalid_arg (spf "in span id: %s" msg)
in
if Bytes.get bs 52 <> '-' then invalid_arg "expected '-' after parent_id";
let sampled =
match int_of_string_opt ("0x" ^ Bytes.sub_string bs 53 2) with
| Some flags -> flags land 1 = 1
| None -> false
in
Ok (make ~remote:true ~sampled ~trace_id ~parent_id ())
with Invalid_argument msg -> Error msg
let of_w3c_trace_context_exn bs =
match of_w3c_trace_context bs with
| Ok t -> t
| Error msg -> invalid_arg @@ spf "invalid w3c trace context: %s" msg
let k_ambient : t Hmap.key = Hmap.Key.create ()