feat(telemetry): enrich RPC and PathFind spans with workflow-identifying attributes

Wire up span attributes that enable filtering/grouping traces by request
characteristics: batch detection, payload size, resource cost category,
command name on WS spans, and pathfinding search parameters (destination
amount/currency, source asset count).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/xrpld/rpc/detail/PathFindSpanNames.h

@@ -84,6 +84,12 @@ inline constexpr auto numPaths = makeStr("pathfind_num_paths");
 inline constexpr auto numRequests = makeStr("pathfind_num_requests");
 /// "pathfind_ledger_index" — pathfind target ledger index.
 inline constexpr auto ledgerIndex = makeStr("pathfind_ledger_index");
+/// "pathfind_dest_amount" — requested destination amount as string.
+inline constexpr auto destAmount = makeStr("pathfind_dest_amount");
+/// "pathfind_dest_currency" — destination currency code.
+inline constexpr auto destCurrency = makeStr("pathfind_dest_currency");
+/// "pathfind_num_source_assets" — candidate source assets count.
+inline constexpr auto numSourceAssets = makeStr("pathfind_num_source_assets");
 }  // namespace attr
 
 }  // namespace xrpl::telemetry::pathfind_span

src/xrpld/rpc/detail/PathRequest.cpp

@@ -594,6 +594,8 @@ PathRequest::findPaths(
     auto span = SpanGuard::span(
         TraceCategory::Rpc, pathfind_span::prefix::pathfind, pathfind_span::op::discover);
     span.setAttribute(pathfind_span::attr::searchLevel, static_cast<int64_t>(level));
+    span.setAttribute(
+        pathfind_span::attr::numSourceAssets, static_cast<int64_t>(sourceAssets.size()));
 
     std::int64_t totalPaths = 0;
     for (auto const& asset : sourceAssets)
@@ -740,6 +742,8 @@ PathRequest::doUpdate(
     auto span = SpanGuard::span(
         TraceCategory::Rpc, pathfind_span::prefix::pathfind, pathfind_span::op::compute);
     span.setAttribute(pathfind_span::attr::fast, fast);
+    span.setAttribute(pathfind_span::attr::destAmount, saDstAmount_.getFullText().c_str());
+    span.setAttribute(pathfind_span::attr::destCurrency, to_string(saDstAmount_.asset()).c_str());
 
     JLOG(journal_.debug()) << iIdentifier_ << " update " << (fast ? "fast" : "normal");
 

src/xrpld/rpc/detail/RPCHandler.cpp

@@ -185,6 +185,7 @@ callMethod(JsonContext& context, Method method, std::string const& name, Object&
         JLOG(context.j.debug()) << "RPC call " << name << " completed in "
                                 << ((end - start).count() / 1000000000.0) << "seconds";
         perfLog.rpcFinish(name, curId);
+        span.setAttribute(rpc_span::attr::loadType, context.loadType.label().c_str());
         // Status::operator bool() returns true when there IS an error
         // (code_ != OK), so the ternary correctly maps error->error, ok->success.
         span.setAttribute(

src/xrpld/rpc/detail/RpcSpanNames.h

@@ -144,6 +144,12 @@ inline constexpr auto rpcRole = makeStr("rpc_role");
 inline constexpr auto rpcStatus = makeStr("rpc_status");
 /// "request_payload_size" — bytes of inbound request payload.
 inline constexpr auto requestPayloadSize = makeStr("request_payload_size");
+/// "is_batch" — whether request is a JSON-RPC batch.
+inline constexpr auto isBatch = makeStr("is_batch");
+/// "batch_size" — number of sub-requests in a batch.
+inline constexpr auto batchSize = makeStr("batch_size");
+/// "load_type" — resource cost category after execution.
+inline constexpr auto loadType = makeStr("load_type");
 }  // namespace attr
 
 // ===== Attribute values ====================================================

src/xrpld/rpc/detail/ServerHandler.cpp

@@ -63,6 +63,7 @@
 #include <algorithm>
 #include <cctype>
 #include <chrono>
+#include <cstdint>
 #include <exception>
 #include <map>
 #include <memory>
@@ -428,6 +429,15 @@ ServerHandler::processSession(
     json::Value const& jv)
 {
     auto span = SpanGuard::span(TraceCategory::Rpc, rpc_span::prefix::rpc, rpc_span::op::wsMessage);
+    if (jv.isMember(jss::command) && jv[jss::command].isString())
+    {
+        span.setAttribute(rpc_span::attr::command, jv[jss::command].asString().c_str());
+    }
+    else if (jv.isMember(jss::method) && jv[jss::method].isString())
+    {
+        span.setAttribute(rpc_span::attr::command, jv[jss::method].asString().c_str());
+    }
+
     auto is = std::static_pointer_cast<WSInfoSub>(session->appDefined);
     if (is->getConsumer().disconnect(journal_))
     {
@@ -576,9 +586,12 @@ ServerHandler::processSession(
     auto span =
         SpanGuard::span(TraceCategory::Rpc, rpc_span::prefix::rpc, rpc_span::op::httpRequest);
 
+    auto const requestBody = ::xrpl::buffersToString(session->request().body().data());
+    span.setAttribute(rpc_span::attr::requestPayloadSize, static_cast<int64_t>(requestBody.size()));
+
     processRequest(
         session->port(),
-        ::xrpl::buffersToString(session->request().body().data()),
+        requestBody,
         session->remoteAddress().atPort(0),
         makeOutput(*session),
         coro,
@@ -657,6 +670,9 @@ ServerHandler::processRequest(
         }
         size = jsonOrig[jss::params].size();
     }
+    span.setAttribute(rpc_span::attr::isBatch, batch);
+    if (batch)
+        span.setAttribute(rpc_span::attr::batchSize, static_cast<int64_t>(size));
 
     json::Value reply(batch ? json::ValueType::Array : json::ValueType::Object);
     auto const start(std::chrono::high_resolution_clock::now());