add support for per-signal urls

src/client-cohttp-lwt/common_.ml

@@ -14,12 +14,30 @@ let debug_ =
 
 let default_url = "http://localhost:4318"
 
-let url =
-  ref (try Sys.getenv "OTEL_EXPORTER_OTLP_ENDPOINT" with _ -> default_url)
-
-let get_url () = !url
-
-let set_url s = url := s
+let make_get_from_env env_name =
+  let value = ref None in
+  fun () ->
+    match !value with
+    | None ->
+      value := Sys.getenv_opt env_name;
+      !value
+    | Some value -> Some value
+
+let get_url_from_env = make_get_from_env "OTEL_EXPORTER_OTLP_ENDPOINT"
+
+let get_url_traces_from_env =
+  make_get_from_env "OTEL_EXPORTER_OTLP_TRACES_ENDPOINT"
+
+let get_url_metrics_from_env =
+  make_get_from_env "OTEL_EXPORTER_OTLP_METRICS_ENDPOINT"
+
+let get_url_logs_from_env = make_get_from_env "OTEL_EXPORTER_OTLP_LOGS_ENDPOINT"
+
+let remove_trailing_slash url =
+  if url <> "" && String.get url (String.length url - 1) = '/' then
+    String.sub url 0 (String.length url - 1)
+  else
+    url
 
 let parse_headers s =
   let parse_header s =

src/client-cohttp-lwt/config.ml

@@ -2,7 +2,9 @@ open Common_
 
 type t = {
   debug: bool;
-  url: string;
+  url_traces: string;
+  url_metrics: string;
+  url_logs: string;
   headers: (string * string) list;
   batch_traces: int option;
   batch_metrics: int option;
@@ -16,7 +18,9 @@ let pp out self : unit =
   let ppheaders = Format.pp_print_list pp_header in
   let {
     debug;
-    url;
+    url_traces;
+    url_metrics;
+    url_logs;
     headers;
     batch_traces;
     batch_metrics;
@@ -26,17 +30,52 @@ let pp out self : unit =
     self
   in
   Format.fprintf out
-    "{@[ debug=%B;@ url=%S;@ headers=%a;@ batch_traces=%a;@ batch_metrics=%a;@ \
-     batch_logs=%a;@ batch_timeout_ms=%d; @]}"
-    debug url ppheaders headers ppiopt batch_traces ppiopt batch_metrics ppiopt
-    batch_logs batch_timeout_ms
+    "{@[ debug=%B;@ url_traces=%S;@ url_metrics=%S;@ url_logs=%S;@ \
+     headers=%a;@ batch_traces=%a;@ batch_metrics=%a;@ batch_logs=%a;@ \
+     batch_timeout_ms=%d; @]}"
+    debug url_traces url_metrics url_logs ppheaders headers ppiopt batch_traces
+    ppiopt batch_metrics ppiopt batch_logs batch_timeout_ms
+
+let make ?(debug = !debug_) ?url ?url_traces ?url_metrics ?url_logs
+    ?(headers = get_headers ()) ?(batch_traces = Some 400)
+    ?(batch_metrics = Some 20) ?(batch_logs = Some 400)
+    ?(batch_timeout_ms = 500) () : t =
+  let url_traces, url_metrics, url_logs =
+    let base_url =
+      match url with
+      | None -> Option.value (get_url_from_env ()) ~default:default_url
+      | Some url -> remove_trailing_slash url
+    in
+    let url_traces =
+      match url_traces with
+      | None ->
+        Option.value
+          (get_url_traces_from_env ())
+          ~default:(base_url ^ "/v1/traces")
+      | Some url -> url
+    in
+    let url_metrics =
+      match url_metrics with
+      | None ->
+        Option.value
+          (get_url_metrics_from_env ())
+          ~default:(base_url ^ "/v1/metrics")
+      | Some url -> url
+    in
+    let url_logs =
+      match url_logs with
+      | None ->
+        Option.value (get_url_logs_from_env ()) ~default:(base_url ^ "/v1/logs")
+      | Some url -> url
+    in
+    url_traces, url_metrics, url_logs
+  in
 
-let make ?(debug = !debug_) ?(url = get_url ()) ?(headers = get_headers ())
-    ?(batch_traces = Some 400) ?(batch_metrics = Some 20)
-    ?(batch_logs = Some 400) ?(batch_timeout_ms = 500) () : t =
   {
     debug;
-    url;
+    url_traces;
+    url_metrics;
+    url_logs;
     headers;
     batch_traces;
     batch_metrics;

src/client-cohttp-lwt/config.mli

@@ -1,8 +1,8 @@
 type t = private {
   debug: bool;
-  url: string;
-      (** Url of the endpoint. Default is "http://localhost:4318",
-      or "OTEL_EXPORTER_OTLP_ENDPOINT" if set. *)
+  url_traces: string;  (** Url to send traces *)
+  url_metrics: string;  (** Url to send metrics*)
+  url_logs: string;  (** Url to send logs *)
   headers: (string * string) list;
       (** API headers sent to the endpoint. Default is none or
       "OTEL_EXPORTER_OTLP_HEADERS" if set. *)
@@ -37,6 +37,9 @@ type t = private {
 val make :
   ?debug:bool ->
   ?url:string ->
+  ?url_traces:string ->
+  ?url_metrics:string ->
+  ?url_logs:string ->
   ?headers:(string * string) list ->
   ?batch_traces:int option ->
   ?batch_metrics:int option ->
@@ -49,6 +52,25 @@ val make :
    @param thread if true and [bg_threads] is not provided, we will pick a number
    of bg threads. Otherwise the number of [bg_threads] superseeds this option.
 
+   @param url base url used to construct per-signal urls. Per-signal url options take precedence over this base url.
+   Default is "http://localhost:4318", or "OTEL_EXPORTER_OTLP_ENDPOINT" if set.
+
+   Example of constructed per-signal urls with the base url http://localhost:4318
+   - Traces: http://localhost:4318/v1/traces
+   - Metrics: http://localhost:4318/v1/metrics
+   - Logs: http://localhost:4318/v1/logs
+
+   Use per-signal url options if different urls are needed for each signal type.
+
+   @param url_traces url to send traces, or "OTEL_EXPORTER_OTLP_TRACES_ENDPOINT" if set.
+   The url is used as-is without any modification.
+
+   @param url_metrics url to send metrics, or "OTEL_EXPORTER_OTLP_METRICS_ENDPOINT" if set.
+   The url is used as-is without any modification.
+
+   @param url_logs url to send logs, or "OTEL_EXPORTER_OTLP_LOGS_ENDPOINT" if set.
+   The url is used as-is without any modification.
+
  *)
 
 val pp : Format.formatter -> t -> unit

src/client-cohttp-lwt/opentelemetry_client_cohttp_lwt.ml

@@ -73,7 +73,7 @@ module Httpc : sig
   val send :
     t ->
     config:Config.t ->
-    path:string ->
+    url:string ->
     decode:[ `Dec of Pbrt.Decoder.t -> 'a | `Ret of 'a ] ->
     string ->
     ('a, error) result Lwt.t
@@ -91,17 +91,9 @@ end = struct
   let cleanup _self = ()
 
   (* send the content to the remote endpoint/path *)
-  let send (_self : t) ~(config : Config.t) ~path ~decode (bod : string) :
+  let send (_self : t) ~(config : Config.t) ~url ~decode (bod : string) :
       ('a, error) result Lwt.t =
-    let url =
-      let url = config.url in
-      if url <> "" && String.get url (String.length url - 1) = '/' then
-        String.sub url 0 (String.length url - 1)
-      else
-        url
-    in
-    let full_url = url ^ path in
-    let uri = Uri.of_string full_url in
+    let uri = Uri.of_string url in
 
     let open Cohttp in
     let headers = Header.(add_list (init ()) !headers) in
@@ -121,7 +113,7 @@ end = struct
     | Error e ->
       let err =
         `Failure
-          (spf "sending signals via http POST to %S\nfailed with:\n%s" full_url
+          (spf "sending signals via http POST to %S\nfailed with:\n%s" url
              (Printexc.to_string e))
       in
       Lwt.return @@ Error err
@@ -158,7 +150,7 @@ end = struct
                     %s\n\
                     status: %S\n\
                     %s"
-                   full_url code (Printexc.to_string e) body bt))
+                   url code (Printexc.to_string e) body bt))
         in
         Lwt.return r
       )
@@ -292,11 +284,11 @@ let mk_emitter ~stop ~(config : Config.t) () : (module EMITTER) =
 
     let set_on_tick_callbacks = Atomic.set on_tick_cbs_
 
-    let send_http_ (httpc : Httpc.t) encoder ~path ~encode x : unit Lwt.t =
+    let send_http_ (httpc : Httpc.t) encoder ~url ~encode x : unit Lwt.t =
       Pbrt.Encoder.reset encoder;
       encode x encoder;
       let data = Pbrt.Encoder.to_string encoder in
-      let* r = Httpc.send httpc ~config ~path ~decode:(`Ret ()) data in
+      let* r = Httpc.send httpc ~config ~url ~decode:(`Ret ()) data in
       match r with
       | Ok () -> Lwt.return ()
       | Error `Sysbreak ->
@@ -317,23 +309,26 @@ let mk_emitter ~stop ~(config : Config.t) () : (module EMITTER) =
         Metrics_service.default_export_metrics_service_request
           ~resource_metrics:l ()
       in
-      send_http_ curl encoder ~path:"/v1/metrics"
+      let url = config.Config.url_metrics in
+      send_http_ curl encoder ~url
         ~encode:Metrics_service.encode_pb_export_metrics_service_request x
 
     let send_traces_http curl encoder (l : Trace.resource_spans list list) =
       let l = List.fold_left (fun acc l -> List.rev_append l acc) [] l in
       let x =
         Trace_service.default_export_trace_service_request ~resource_spans:l ()
       in
-      send_http_ curl encoder ~path:"/v1/traces"
+      let url = config.Config.url_traces in
+      send_http_ curl encoder ~url
         ~encode:Trace_service.encode_pb_export_trace_service_request x
 
     let send_logs_http curl encoder (l : Logs.resource_logs list list) =
       let l = List.fold_left (fun acc l -> List.rev_append l acc) [] l in
       let x =
         Logs_service.default_export_logs_service_request ~resource_logs:l ()
       in
-      send_http_ curl encoder ~path:"/v1/logs"
+      let url = config.Config.url_logs in
+      send_http_ curl encoder ~url
         ~encode:Logs_service.encode_pb_export_logs_service_request x
 
     (* emit metrics, if the batch is full or timeout lapsed *)
@@ -459,12 +454,13 @@ let mk_emitter ~stop ~(config : Config.t) () : (module EMITTER) =
   end in
   (module M)
 
-module Backend (Arg : sig
-  val stop : bool Atomic.t
+module Backend
+    (Arg : sig
+      val stop : bool Atomic.t
 
-  val config : Config.t
-end)
-() : Opentelemetry.Collector.BACKEND = struct
+      val config : Config.t
+    end)
+    () : Opentelemetry.Collector.BACKEND = struct
   include (val mk_emitter ~stop:Arg.stop ~config:Arg.config ())
 
   open Opentelemetry.Proto
@@ -475,10 +471,10 @@ end)
       send =
         (fun l ~ret ->
           (if !debug_ then
-            let@ () = Lock.with_lock in
-            Format.eprintf "send spans %a@."
-              (Format.pp_print_list Trace.pp_resource_spans)
-              l);
+             let@ () = Lock.with_lock in
+             Format.eprintf "send spans %a@."
+               (Format.pp_print_list Trace.pp_resource_spans)
+               l);
           push_trace l;
           ret ());
     }
@@ -532,10 +528,10 @@ end)
       send =
         (fun m ~ret ->
           (if !debug_ then
-            let@ () = Lock.with_lock in
-            Format.eprintf "send metrics %a@."
-              (Format.pp_print_list Metrics.pp_resource_metrics)
-              m);
+             let@ () = Lock.with_lock in
+             Format.eprintf "send metrics %a@."
+               (Format.pp_print_list Metrics.pp_resource_metrics)
+               m);
 
           let m = List.rev_append (additional_metrics ()) m in
           push_metrics m;
@@ -547,10 +543,10 @@ end)
       send =
         (fun m ~ret ->
           (if !debug_ then
-            let@ () = Lock.with_lock in
-            Format.eprintf "send logs %a@."
-              (Format.pp_print_list Logs.pp_resource_logs)
-              m);
+             let@ () = Lock.with_lock in
+             Format.eprintf "send logs %a@."
+               (Format.pp_print_list Logs.pp_resource_logs)
+               m);
 
           push_logs m;
           ret ());
@@ -560,8 +556,6 @@ end
 let create_backend ?(stop = Atomic.make false) ?(config = Config.make ()) () =
   debug_ := config.debug;
 
-  if config.url <> get_url () then set_url config.url;
-
   let module B =
     Backend
       (struct

src/client-cohttp-lwt/opentelemetry_client_cohttp_lwt.mli

@@ -5,12 +5,6 @@
 
 open Common_
 
-val get_url : unit -> string
-
-val set_url : string -> unit
-(** Url of the endpoint. Default is "http://localhost:4318",
-    or "OTEL_EXPORTER_OTLP_ENDPOINT" if set. *)
-
 val get_headers : unit -> (string * string) list
 
 val set_headers : (string * string) list -> unit

src/client-ocurl/common_.ml

@@ -15,12 +15,30 @@ let debug_ =
 
 let default_url = "http://localhost:4318"
 
-let url =
-  ref (try Sys.getenv "OTEL_EXPORTER_OTLP_ENDPOINT" with _ -> default_url)
-
-let get_url () = !url
-
-let set_url s = url := s
+let make_get_from_env env_name =
+  let value = ref None in
+  fun () ->
+    match !value with
+    | None ->
+      value := Sys.getenv_opt env_name;
+      !value
+    | Some value -> Some value
+
+let get_url_from_env = make_get_from_env "OTEL_EXPORTER_OTLP_ENDPOINT"
+
+let get_url_traces_from_env =
+  make_get_from_env "OTEL_EXPORTER_OTLP_TRACES_ENDPOINT"
+
+let get_url_metrics_from_env =
+  make_get_from_env "OTEL_EXPORTER_OTLP_METRICS_ENDPOINT"
+
+let get_url_logs_from_env = make_get_from_env "OTEL_EXPORTER_OTLP_LOGS_ENDPOINT"
+
+let remove_trailing_slash url =
+  if url <> "" && String.get url (String.length url - 1) = '/' then
+    String.sub url 0 (String.length url - 1)
+  else
+    url
 
 let parse_headers s =
   let parse_header s =