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https://github.com/ocaml-tracing/ocaml-opentelemetry.git
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59 lines
1.8 KiB
OCaml
59 lines
1.8 KiB
OCaml
open Cohttp
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open Cohttp_lwt
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type ('conn, 'body) callback =
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'conn (* Cohttp_lwt_unix.Server.conn *)
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-> Request.t
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-> 'body (* Cohttp_lwt.Body.t *)
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-> (Response.t * 'body) Lwt.t
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let span_attrs (req : Request.t) =
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let meth = req |> Request.meth |> Code.string_of_method in
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let referer = Header.get (Request.headers req) "referer" in
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let host = Header.get (Request.headers req) "host" in
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let ua = Header.get (Request.headers req) "user-agent" in
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let uri = Request.uri req in
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List.concat
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[ [ ("http.method", `String meth) ]
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; (match host with None -> [] | Some h -> [ ("http.host", `String h) ])
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; [ ("http.url", `String (Uri.to_string uri)) ]
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; ( match ua with
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| None ->
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[]
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| Some ua ->
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[ ("http.user_agent", `String ua) ] )
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; ( match referer with
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| None ->
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[]
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| Some r ->
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[ ("http.request.header.referer", `String r) ] )
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]
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let trace ~service_name (callback : ('conn, 'body) callback ) : ('conn, 'body) callback =
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fun conn req body ->
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let trace_id =
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Header.get (Request.headers req) "trace-id"
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|> Option.map (fun s ->
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s |> Bytes.of_string |> Opentelemetry.Trace_id.of_bytes )
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in
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let parent_id =
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Header.get (Request.headers req) "parent-id"
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|> Option.map (fun s ->
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s |> Bytes.of_string |> Opentelemetry.Span_id.of_bytes )
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in
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let open Lwt.Syntax in
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Opentelemetry_lwt.Trace.with_
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~service_name
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"request"
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~kind:Span_kind_server
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~attrs:(span_attrs req)
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?parent:parent_id
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?trace_id
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(fun scope ->
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let* (res, body) = callback conn req body in
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Opentelemetry.Trace.add_attrs scope (fun () ->
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let code = Response.status res in
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let code = Code.code_of_status code in
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[ ("http.status_code", `Int code) ]) ;
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Lwt.return (res, body) )
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