Refactor runtime_id into span defaults, available to tracer telemetry

Author: cgilmour

src/datadog/span_defaults.cpp

@@ -22,6 +22,7 @@ nlohmann::json to_json(const SpanDefaults& defaults) {
   TO_JSON(version);
   TO_JSON(name);
   TO_JSON(tags);
+  TO_JSON(runtime_id);
 #undef TO_JSON
   return result;
 }

src/datadog/span_defaults.h

@@ -8,6 +8,7 @@
 #include <unordered_map>
 
 #include "json_fwd.hpp"
+#include "random.h"
 
 namespace datadog {
 namespace tracing {
@@ -19,6 +20,7 @@ struct SpanDefaults {
   std::string version = "";
   std::string name = "";
   std::unordered_map<std::string, std::string> tags;
+  std::string runtime_id = uuid();
 };
 
 nlohmann::json to_json(const SpanDefaults&);

src/datadog/trace_segment.cpp

@@ -16,6 +16,7 @@
 #include "platform_util.h"
 #include "random.h"
 #include "span_data.h"
+#include "span_defaults.h"
 #include "span_sampler.h"
 #include "tag_propagation.h"
 #include "tags.h"
@@ -28,12 +29,8 @@ namespace {
 
 struct Cache {
   static int process_id;
-  static std::string runtime_id;
 
-  static void recalculate_values() {
-    process_id = get_process_id();
-    runtime_id = uuid();
-  }
+  static void recalculate_values() { process_id = get_process_id(); }
 
   Cache() {
     recalculate_values();
@@ -42,7 +39,6 @@ struct Cache {
 };
 
 int Cache::process_id;
-std::string Cache::runtime_id;
 
 // `cache_singleton` exists solely to invoke `Cache`'s constructor.
 // All data members are static, so use e.g. `Cache::process_id` instead of
@@ -218,7 +214,7 @@ void TraceSegment::span_finished() {
     }
     span.numeric_tags[tags::internal::process_id] = Cache::process_id;
     span.tags[tags::internal::language] = "cpp";
-    span.tags[tags::internal::runtime_id] = Cache::runtime_id;
+    span.tags[tags::internal::runtime_id] = defaults_->runtime_id;
   }
 
   const auto result = collector_->send(std::move(spans_), trace_sampler_);

src/datadog/tracer_telemetry.cpp

@@ -59,7 +59,7 @@ std::string TracerTelemetry::app_started(nlohmann::json&& tracer_config) {
               {"seq_id", seq_id},
               {"request_type", "app-started"},
               {"tracer_time", tracer_time},
-              {"runtime_id", "0524398a-11e2-4375-a637-619eb9148e8f"},
+              {"runtime_id", span_defaults_->runtime_id},
               {"debug", true},
               {"application",
                nlohmann::json::object({
@@ -149,7 +149,7 @@ std::string TracerTelemetry::heartbeat_and_telemetry() {
               {"seq_id", seq_id},
               {"request_type", "message-batch"},
               {"tracer_time", tracer_time},
-              {"runtime_id", "0524398a-11e2-4375-a637-619eb9148e8f"},
+              {"runtime_id", span_defaults_->runtime_id},
               {"debug", true},
               {"application",
                nlohmann::json::object({