Merge branch 'pratik/otel-phase1b-telemetry-infra' into pratik/otel-phase1c-rpc-integration

Signed-off-by: Pratik Mankawde <3397372+pratikmankawde@users.noreply.github.com>

docs/build/telemetry.md

@@ -36,7 +36,8 @@ such as Grafana Tempo.
 Telemetry is **off by default** at both compile time and runtime:
 
 - **Compile time**: The Conan option `telemetry` and CMake option `telemetry` must be set to `True`/`ON`.
-  When disabled, all tracing macros compile to `((void)0)` with zero overhead.
+  When disabled, all `SpanGuard` calls compile to inline no-ops (defined in `SpanGuard.h`)
+  with zero overhead — no OTel SDK dependency required.
 - **Runtime**: The `[telemetry]` config section must set `enabled=1`.
   When disabled at runtime, a no-op implementation is used.
 

include/xrpl/protocol/detail/features.macro

@@ -15,7 +15,6 @@
 // Add new amendments to the top of this list.
 // Keep it sorted in reverse chronological order.
 
-XRPL_FIX    (Cleanup3_2_0,                Supported::no, VoteBehavior::DefaultNo)
 XRPL_FEATURE(MPTokensV2,                  Supported::no, VoteBehavior::DefaultNo)
 XRPL_FIX    (Security3_1_3,               Supported::no, VoteBehavior::DefaultNo)
 XRPL_FIX    (PermissionedDomainInvariant, Supported::yes, VoteBehavior::DefaultNo)

include/xrpl/telemetry/Telemetry.h

@@ -35,19 +35,18 @@
 
     Usage examples:
 
-    1. Check before tracing (typical guard pattern):
+    1. Root span at a subsystem entry point (typical usage):
     @code
-        auto& telemetry = registry.getTelemetry();
-        if (telemetry.isEnabled() && telemetry.shouldTraceRpc())
-        {
-            auto span = telemetry.startSpan("rpc.command.server_info");
-            // ... do work, span ends when shared_ptr refcount drops to 0
-        }
+        // In an RPC handler dispatch:
+        auto guard = SpanGuard::span(TraceCategory::Rpc, "rpc", commandName);
+        guard.setAttribute("xrpl.rpc.command", commandName);
+        // ... process request
+        // guard destructor automatically ends the span on scope exit
     @endcode
 
-    2. RAII tracing with SpanGuard (preferred):
+    2. Child span for a sub-operation (cross-scope):
     @code
-        if (telemetry.isEnabled() && telemetry.shouldTraceRpc())
+        auto parent = SpanGuard::span(TraceCategory::Transactions, "tx", "process");
         {
             SpanGuard guard(telemetry.startSpan("rpc.command.submit"));
             guard.setAttribute("command", "submit");
@@ -55,12 +54,24 @@
         }
     @endcode
 
-    3. Cross-thread context propagation:
+    3. Child span for a sub-operation (cross-scope):
     @code
-        // On thread A: capture context
-        auto ctx = guard.context();
-        // On thread B: create child span with explicit parent
-        auto child = telemetry.startSpan("async.work", ctx);
+        auto parent = SpanGuard::span(TraceCategory::Transactions, "tx", "process");
+        {
+            auto child = parent.childSpan("tx.apply");
+            child.setAttribute("xrpl.tx.type", txType);
+            // child ends here
+        }
+        // parent continues, then ends here
+    @endcode
+
+    4. Cross-thread context propagation:
+    @code
+        // Thread A: capture the active context while span is in scope
+        auto ctx = parentGuard.captureContext();
+
+        // Thread B: create child span with explicit parent
+        auto child = SpanGuard::childSpan("async.work", ctx);
     @endcode
 
     @note Thread safety: The Telemetry interface is safe for concurrent reads

src/libxrpl/telemetry/SpanGuard.cpp

@@ -36,6 +36,7 @@
 #include <opentelemetry/trace/tracer.h>
 
 #include <string>
+#include <typeinfo>
 #include <utility>
 
 namespace xrpl {
@@ -332,7 +333,7 @@ SpanGuard::recordException(std::exception const& e)
         return;
     impl_->span->AddEvent(
         "exception",
-        {{"exception.type", "std::exception"}, {"exception.message", std::string(e.what())}});
+        {{"exception.type", typeid(e).name()}, {"exception.message", std::string(e.what())}});
     impl_->span->SetStatus(otel_trace::StatusCode::kError, e.what());
 }