OpenTelemetry Implementation

auto/help

@@ -52,6 +52,8 @@ cat << END
 
   --njs                enable njs library usage
 
+  --otel               enable otel library usage
+
   --debug              enable debug logging
 
   --fuzz=ENGINE        enable fuzz testing

auto/options

@@ -27,6 +27,7 @@ NXT_CYASSL=NO
 NXT_POLARSSL=NO
 
 NXT_NJS=NO
+NXT_OTEL=NO
 
 NXT_TEST_BUILD_EPOLL=NO
 NXT_TEST_BUILD_EVENTPORT=NO
@@ -112,6 +113,7 @@ do
         --polarssl)                      NXT_POLARSSL=YES                    ;;
 
         --njs)                           NXT_NJS=YES                         ;;
+        --otel)                          NXT_OTEL=YES                        ;;
 
         --test-build-epoll)              NXT_TEST_BUILD_EPOLL=YES            ;;
         --test-build-eventport)          NXT_TEST_BUILD_EVENTPORT=YES        ;;

auto/otel

@@ -0,0 +1,25 @@
+
+# Copyright (C) NGINX, Inc.
+
+
+nxt_found=no
+NXT_HAVE_OTEL=NO
+
+NXT_OTEL_LIB_LOC=src/otel/target/debug/libotel.a
+
+cat << END >> $NXT_AUTO_CONFIG_H
+#ifndef NXT_HAVE_OTEL
+#define NXT_HAVE_OTEL 1
+#endif
+END
+
+NXT_LIB_AUX_LIBS="$NXT_LIB_AUX_LIBS $(pkgconf openssl --cflags --libs || "-lssl -lcrypto") $NXT_OTEL_LIB_LOC"
+
+cat << END >> $NXT_MAKEFILE
+
+$NXT_OTEL_LIB_LOC:
+    pushd $NXT_BUILD_DIR/src/otel/
+    cargo build
+    cd ../../
+
+END

auto/sources

@@ -127,6 +127,10 @@ if [ "$NXT_NJS" != "NO" ]; then
     NXT_LIB_SRCS="$NXT_LIB_SRCS src/nxt_js.c src/nxt_http_js.c src/nxt_script.c"
 fi
 
+if [ "$NXT_OTEL" != "NO" ]; then
+    NXT_LIB_SRCS="$NXT_LIB_SRCS src/nxt_otel.c"
+fi
+
 NXT_LIB_EPOLL_SRCS="src/nxt_epoll_engine.c"
 NXT_LIB_KQUEUE_SRCS="src/nxt_kqueue_engine.c"
 NXT_LIB_EVENTPORT_SRCS="src/nxt_eventport_engine.c"

auto/ssltls

@@ -212,4 +212,4 @@ if [ $NXT_POLARSSL = YES ]; then
         $echo
         exit 1;
     fi
-fi
+fi

auto/summary

@@ -30,6 +30,7 @@ Unit configuration summary:
   TLS support: ............... $NXT_OPENSSL
   Regex support: ............. $NXT_REGEX
   njs support: ............... $NXT_NJS
+  otel support: .............. $NXT_OTEL
 
   process isolation: ......... $NXT_ISOLATION
   cgroupv2: .................. $NXT_HAVE_CGROUP

configure

@@ -179,6 +179,10 @@ if [ $NXT_NJS != NO ]; then
     . auto/njs
 fi
 
+if [ $NXT_OTEL != NO ]; then
+    . auto/otel
+fi
+
 . auto/make
 . auto/fuzzing
 . auto/summary

docs/unit-openapi.yaml

@@ -3090,6 +3090,68 @@ paths:
         "404":
           $ref: "#/components/responses/responseNotFound"
 
+  /config/settings/telemetry:
+    summary: "Endpoint for the `telemetry` object in `settings`"
+    get:
+      operationId: getSettingsTelemetry
+      summary: "Retrieve the `telemetry` object from settings"
+      description: "Retrieves the `telemetry` object that represents Unit's
+        [Telemetry settings](https://unit.nginx.org/configuration/#settings)."
+      tags:
+        - settings
+        - config
+      responses:
+        "200":
+          description: "Ok; the `telemetry` object exists in the configuration."
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/configSettingsTelemetry"
+        "404":
+          $ref: "#/components/responses/responseNotFound"
+
+    put:
+      operationId: putSettingsTelemetry
+      summary: "Create or update the `telemetry` object in settings"
+      description: "Creates or updates the `telemetry` object that represents Unit's
+        [Telemetry settings](https://unit.nginx.org/configuration/#settings)."
+      tags:
+        - settings
+        - config
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/configSettingsTelemetry"
+      responses:
+        "200":
+          $ref: "#/components/responses/responseOkUpdated"
+
+        "400":
+          $ref: "#/components/responses/responseBadRequest"
+
+        "404":
+          $ref: "#/components/responses/responseNotFound"
+
+        "500":
+          $ref: "#/components/responses/responseInternalError"
+
+    delete:
+      operationId: deleteSettingsTelemetry
+      summary: "Delete the telemetry object"
+      description: "Deletes the `telemetry` object from the configuration."
+      tags:
+        - settings
+        - config
+
+      responses:
+        "200":
+          $ref: "#/components/responses/responseOkDeleted"
+
+        "404":
+          $ref: "#/components/responses/responseNotFound"
+
   /config/settings/http:
     summary: "Endpoint for the `http` object in `settings`"
 
@@ -6545,10 +6607,33 @@ components:
         Unit settings."
 
       properties:
+        telemetry:
+          description: "Represents global telemetry settings in Unit."
+          $ref: "#/components/schemas/configSettingsTelemetry"
+
         http:
           description: "Represents global HTTP settings in Unit."
           $ref: "#/components/schemas/configSettingsHttp"
 
+    # /config/settings/telemetry
+    configSettingsTelemetry:
+      type: object
+      description: "An object whose options represent global telemetry settings in Unit."
+      required: ["endpoint"]
+      properties:
+        batch_size:
+          type: integer
+          description: "Number of spans to cache before sending to telemetry collector."
+          default: 128
+
+        endpoint:
+          type: string
+          description: "A valid endpoint to which Unit can send OpenTelemetry spans."
+
+        protocol:
+          type: string
+          description: "Protocol to use when communicating with the aforementioned endpoint."
+
     # /config/settings/http
     configSettingsHttp:
       type: object

src/nxt_conf_validation.c

@@ -307,6 +307,30 @@ static nxt_conf_vldt_object_t  nxt_conf_vldt_root_members[] = {
 };
 
 
+
+#if (NXT_HAVE_OTEL)
+static nxt_conf_vldt_object_t nxt_conf_vldt_otel_members[] = {
+    {
+        .name      = nxt_string("endpoint"),
+        .type      = NXT_CONF_VLDT_STRING,
+        .validator = nxt_otel_validate_endpoint,
+        .flags     = NXT_CONF_VLDT_REQUIRED
+    }, {
+        .name      = nxt_string("batch_size"),
+        .type      = NXT_CONF_VLDT_INTEGER,
+        .validator = nxt_otel_validate_batch_size,
+    }, {
+        .name      = nxt_string("protocol"),
+        .type      = NXT_CONF_VLDT_STRING,
+        .validator = nxt_otel_validate_protocol,
+        .flags     = NXT_CONF_VLDT_REQUIRED
+    },
+
+    NXT_CONF_VLDT_END
+};
+#endif
+
+
 static nxt_conf_vldt_object_t  nxt_conf_vldt_setting_members[] = {
     {
         .name       = nxt_string("listen_threads"),
@@ -317,6 +341,13 @@ static nxt_conf_vldt_object_t  nxt_conf_vldt_setting_members[] = {
         .type       = NXT_CONF_VLDT_OBJECT,
         .validator  = nxt_conf_vldt_object,
         .u.members  = nxt_conf_vldt_http_members,
+#if (NXT_HAVE_OTEL)
+    }, {
+        .name       = nxt_string("telemetry"),
+        .type       = NXT_CONF_VLDT_OBJECT,
+        .validator  = nxt_conf_vldt_object,
+        .u.members  = nxt_conf_vldt_otel_members,
+#endif
 #if (NXT_HAVE_NJS)
     }, {
         .name       = nxt_string("js_module"),

src/nxt_h1proto.c

@@ -178,6 +178,10 @@ static nxt_http_field_proc_t           nxt_h1p_fields[] = {
     { nxt_string("Content-Length"),    &nxt_http_request_content_length, 0 },
     { nxt_string("Authorization"),     &nxt_http_request_field,
         offsetof(nxt_http_request_t, authorization) },
+#if (NXT_HAVE_OTEL)
+    { nxt_string("Traceparent"),       &nxt_otel_parse_traceparent, 0 },
+    { nxt_string("Tracestate"),        &nxt_otel_parse_tracestate,  0 },
+#endif
 };
 
 
@@ -518,6 +522,10 @@ nxt_h1p_conn_request_init(nxt_task_t *task, void *obj, void *data)
             h1p->parser.discard_unsafe_fields = skcf->discard_unsafe_fields;
 
             nxt_h1p_conn_request_header_parse(task, c, h1p);
+#if (NXT_HAVE_OTEL)
+            nxt_otel_test_and_call_state(task, r);
+#endif
+
             return;
         }
 
@@ -1685,6 +1693,10 @@ nxt_h1p_request_discard(nxt_task_t *task, nxt_http_request_t *r,
 
     nxt_sendbuf_drain(task, wq, b);
     nxt_sendbuf_drain(task, wq, last);
+
+#if (NXT_HAVE_OTEL)
+    nxt_otel_test_and_call_state(task, r);
+#endif
 }
 
 
@@ -1824,6 +1836,12 @@ nxt_h1p_conn_sent(nxt_task_t *task, void *obj, void *data)
 {
     nxt_conn_t          *c;
     nxt_event_engine_t  *engine;
+#if (NXT_HAVE_OTEL)
+    nxt_http_request_t  *r;
+
+    r = ((nxt_h1proto_t *) data)->request;
+    nxt_otel_test_and_call_state(task, r);
+#endif
 
     c = obj;
 

src/nxt_http.h

@@ -8,6 +8,7 @@
 #define _NXT_HTTP_H_INCLUDED_
 
 #include <nxt_regex.h>
+#include <nxt_otel.h>
 
 
 typedef enum {
@@ -190,6 +191,10 @@ struct nxt_http_request_s {
 
     nxt_http_response_t             resp;
 
+#if (NXT_HAVE_OTEL)
+    nxt_otel_state_t                *otel;
+#endif
+
     nxt_http_status_t               status:16;
 
     uint8_t                         log_route;    /* 1 bit */

src/nxt_http_request.c

@@ -283,7 +283,15 @@ nxt_http_request_create(nxt_task_t *task)
     task->thread->engine->requests_cnt++;
 
     r->tstr_cache.var.pool = mp;
-
+#if (NXT_HAVE_OTEL)
+    if (nxt_otel_is_init()) {
+        r->otel = nxt_mp_zget(r->mem_pool, sizeof(nxt_otel_state_t));
+        if (r->otel == NULL) {
+            goto fail;
+        }
+        r->otel->status = NXT_OTEL_INIT_STATE;
+    }
+#endif
     return r;
 
 fail:
@@ -311,6 +319,10 @@ nxt_http_request_start(nxt_task_t *task, void *obj, void *data)
 
     r = obj;
 
+#if (NXT_HAVE_OTEL)
+    nxt_otel_test_and_call_state(task, r);
+#endif
+
     r->state = &nxt_http_request_body_state;
 
     skcf = r->conf->socket_conf;
@@ -582,6 +594,10 @@ nxt_http_request_ready(nxt_task_t *task, void *obj, void *data)
     r = obj;
     action = r->conf->socket_conf->action;
 
+#if (NXT_HAVE_OTEL)
+    nxt_otel_test_and_call_state(task, r);
+#endif
+
     if (r->chunked) {
         ret = nxt_http_request_chunked_transform(r);
         if (nxt_slow_path(ret != NXT_OK)) {
@@ -850,6 +866,11 @@ nxt_http_request_error_handler(nxt_task_t *task, void *obj, void *data)
 
     r->error = 1;
 
+#if (NXT_HAVE_OTEL)
+    // TODO
+    // PHASE 2: add error event to span
+#endif
+
     if (nxt_fast_path(proto.any != NULL)) {
         nxt_http_proto[r->protocol].discard(task, r, nxt_http_buf_last(r));
     }

src/nxt_main.c

@@ -6,11 +6,8 @@
 
 #include <nxt_main.h>
 #include <nxt_runtime.h>
-
-
 extern char  **environ;
 
-
 int nxt_cdecl
 main(int argc, char **argv)
 {