From 7ada57e2a84651d62b23ac86d3b13a12b3ad2e03 Mon Sep 17 00:00:00 2001
From: Pratik Mankawde <3397372+pratikmankawde@users.noreply.github.com>
Date: Thu, 14 May 2026 15:53:59 +0100
Subject: [PATCH] fix(telemetry): map TraceCategory to OTel SpanKind in
 SpanGuard::span()

SpanGuard::span() hardcoded SpanKind::kInternal for every span. Tempo's
service-graph and spanmetrics RED calculations rely on kServer /
kConsumer / kClient / kProducer to classify inbound vs outbound vs
internal operations. With kInternal everywhere, the service graph
collapses to a single self-loop and RED metrics attribute all latency
to internal work.

Add categoryToSpanKind() mapping:
  - Rpc           -> kServer   (inbound synchronous request)
  - Peer          -> kConsumer (inbound async peer message)
  - Transactions  -> kInternal
  - Consensus     -> kInternal
  - Ledger        -> kInternal

Only the single-argument overload is affected; childSpan / linkedSpan
continue to default to kInternal because they represent in-process
continuations of an already-kinded parent.
---
 src/libxrpl/telemetry/SpanGuard.cpp | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/libxrpl/telemetry/SpanGuard.cpp b/src/libxrpl/telemetry/SpanGuard.cpp
index 22c210c7c5..11eda56ed6 100644
--- a/src/libxrpl/telemetry/SpanGuard.cpp
+++ b/src/libxrpl/telemetry/SpanGuard.cpp
@@ -132,6 +132,32 @@ isCategoryEnabled(Telemetry const& tel, TraceCategory cat)
     return false;  // unreachable, silences compiler warning
 }
 
+namespace {
+
+// Map a TraceCategory to an OTel SpanKind so Tempo's service-graph /
+// RED metrics see the correct direction. RPC spans are emitted at the
+// server entry point (handler dispatch), Peer spans at inbound-message
+// receipt. Transactions / Consensus / Ledger are internal processing
+// and keep the default kInternal.
+otel_trace::SpanKind
+categoryToSpanKind(TraceCategory cat)
+{
+    switch (cat)
+    {
+        case TraceCategory::Rpc:
+            return otel_trace::SpanKind::kServer;
+        case TraceCategory::Peer:
+            return otel_trace::SpanKind::kConsumer;
+        case TraceCategory::Transactions:
+        case TraceCategory::Consensus:
+        case TraceCategory::Ledger:
+            return otel_trace::SpanKind::kInternal;
+    }
+    return otel_trace::SpanKind::kInternal;  // unreachable
+}
+
+}  // namespace
+
 SpanGuard
 SpanGuard::span(TraceCategory cat, std::string_view prefix, std::string_view name)
 {
@@ -139,7 +165,7 @@ SpanGuard::span(TraceCategory cat, std::string_view prefix, std::string_view nam
     if (!tel || !tel->isEnabled() || !isCategoryEnabled(*tel, cat))
         return {};
     auto fullName = std::string(prefix) + "." + std::string(name);
-    return SpanGuard(std::make_unique<Impl>(tel->startSpan(fullName)));
+    return SpanGuard(std::make_unique<Impl>(tel->startSpan(fullName, categoryToSpanKind(cat))));
 }
 
 // ===== Child / linked span creation ========================================