pass query traceparent

Author: cameron-p-m

src/postgres/src/backend/tcop/pquery.c

@@ -1257,7 +1257,6 @@ PortalRunMulti(Portal portal,
 			 * process a plannable query.
 			 */
 			TRACE_POSTGRESQL_QUERY_EXECUTE_START();
-			YBCOtelExecuteStart();
 
 			if (log_executor_stats)
 				ResetUsage();
@@ -1322,7 +1321,6 @@ PortalRunMulti(Portal portal,
 			if (log_executor_stats)
 				ShowUsage("EXECUTOR STATISTICS");
 
-			YBCOtelExecuteDone();
 			TRACE_POSTGRESQL_QUERY_EXECUTE_DONE();
 		}
 		else

src/yb/rpc/outbound_call.cc

@@ -243,8 +243,10 @@ OutboundCall::OutboundCall(const RemoteMethod& remote_method,
   IncrementCounter(rpc_metrics_->outbound_calls_created);
   IncrementGauge(rpc_metrics_->outbound_calls_alive);
 
-  if (OtelTracing::HasActiveContext()) {
-    otel_span_ = OtelTracing::StartSpan(Format("rpc.client $0", remote_method_.ToString()));
+  const auto& traceparent = controller_->traceparent();
+  if (!traceparent.empty()) {
+    otel_span_ = OtelTracing::StartSpanFromTraceparent(
+        Format("rpc.client $0", remote_method_.ToString()), traceparent);
     if (otel_span_.IsActive()) {
       otel_span_.SetAttribute("rpc.system", "yugabytedb");
       otel_span_.SetAttribute("rpc.service", remote_method_.service_name());

src/yb/rpc/rpc_controller.h

@@ -32,6 +32,7 @@
 #pragma once
 
 #include <memory>
+#include <string>
 
 #include "yb/util/logging.h"
 
@@ -139,6 +140,11 @@ class RpcController {
 
   InvokeCallbackMode invoke_callback_mode() { return invoke_callback_mode_; }
 
+  // Set the traceparent for distributed tracing. If set, the RPC will create
+  // a child span under this traceparent. If not set, no tracing span is created.
+  void set_traceparent(const std::string& traceparent) { traceparent_ = traceparent; }
+  const std::string& traceparent() const { return traceparent_; }
+
   // Return the configured timeout.
   MonoDelta timeout() const;
 
@@ -183,6 +189,7 @@ class RpcController {
 
   std::unique_ptr<Sidecars> outbound_sidecars_;
   bool TEST_disable_outbound_call_response_processing = false;
+  std::string traceparent_;
 
   DISALLOW_COPY_AND_ASSIGN(RpcController);
 };

src/yb/util/otel_tracing.cc

@@ -418,4 +418,21 @@ bool OtelTracing::HasActiveContext() {
   return current_span && current_span->GetContext().IsValid();
 }
 
+std::string OtelTracing::GetCurrentTraceparent() {
+  if (!IsEnabled()) {
+    return "";
+  }
+  auto current_span = trace_api::Tracer::GetCurrentSpan();
+  if (!current_span || !current_span->GetContext().IsValid()) {
+    return "";
+  }
+
+  auto span_context = current_span->GetContext();
+  std::string trace_id = TraceIdToHex(span_context.trace_id());
+  std::string span_id = SpanIdToHex(span_context.span_id());
+  std::string flags = span_context.IsSampled() ? "01" : "00";
+
+  return "00-" + trace_id + "-" + span_id + "-" + flags;
+}
+
 }  // namespace yb

src/yb/util/otel_tracing.h

@@ -65,6 +65,7 @@ class OtelTracing {
   static void AdoptSpan(const OtelSpanHandle& span);
   static void EndCurrentSpan();
   static bool HasActiveContext();
+  static std::string GetCurrentTraceparent();
 
  private:
   OtelTracing() = delete;

src/yb/yql/pggate/pg_client.cc

@@ -1656,6 +1656,7 @@ class PgClient::Impl : public BigDataFetcher {
     } else {
       controller->set_timeout(timeout_);
     }
+    controller->set_traceparent(OtelTracing::GetCurrentTraceparent());
     return controller;
   }