Merge branch 'pratik/otel-phase8-log-correlation' into pratik/otel-phase9-metric-gap-fill

# Conflicts:
#	src/xrpld/app/misc/detail/TxQ.cpp

include/xrpl/tx/detail/TxApplySpanNames.h

@@ -0,0 +1,109 @@
+#pragma once
+
+/** Compile-time span name constants for the transaction apply pipeline.
+ *
+ *  Defines the span names and attribute keys used by the three apply-pipeline
+ *  stages — preflight, preclaim, and transactor (apply) — that run inside the
+ *  library (`src/libxrpl/tx/`). Built on the StaticStr/join() primitives from
+ *  <xrpl/telemetry/SpanNames.h>.
+ *
+ *  Why a separate header from TxSpanNames.h:
+ *  TxSpanNames.h lives under src/xrpld/ (daemon) and serves the overlay/app
+ *  lifecycle spans (tx.receive, tx.process). Library code (applySteps.cpp,
+ *  Transactor.cpp) must not depend on daemon headers, so the apply-pipeline
+ *  constants live here instead. The attribute strings ("tx_type",
+ *  "ter_result", "applied") intentionally match TxSpanNames.h so the collector
+ *  spanmetrics connector aggregates both sets under the same dimensions.
+ *
+ *  Span hierarchy (deterministic trace_id derived from txID[0:16]):
+ *
+ *  The three stages run sequentially and often on different threads, so they
+ *  do not auto-parent. Each uses a hash-derived trace_id keyed on the same
+ *  transaction id, placing all three under one trace without context
+ *  propagation. A transaction that hard-fails preflight or preclaim never
+ *  reaches the transactor span — the stage attribute identifies where it
+ *  stopped.
+ *
+ *    +-----------------------------------------------------------+
+ *    | trace_id = txID[0:16]                                     |
+ *    |                                                           |
+ *    |  +-------------------+   +------------------+   +-------+  |
+ *    |  | tx.preflight      |   | tx.preclaim      |   | tx.   |  |
+ *    |  | stage=preflight   |-->| stage=preclaim   |-->| trans |  |
+ *    |  | tx_type           |   | tx_type          |   | actor |  |
+ *    |  | ter_result        |   | ter_result       |   | stage=|  |
+ *    |  +-------------------+   +------------------+   | apply |  |
+ *    |   stateless checks       ledger-aware checks   +-------+  |
+ *    |   (signature, fields)    (sequence, fee)        applies   |
+ *    +-----------------------------------------------------------+
+ *
+ *  Usage:
+ *  @code
+ *      #include <xrpl/tx/detail/TxApplySpanNames.h>
+ *      using namespace telemetry;
+ *
+ *      // preflight() / preclaim() use hashSpan with a full span name:
+ *      auto span = SpanGuard::hashSpan(
+ *          TraceCategory::Transactions, tx_apply_span::preflight,
+ *          txID.data(), txID.kBytes);
+ *      span.setAttribute(tx_apply_span::attr::stage, tx_apply_span::val::preflight);
+ *      span.setAttribute(tx_apply_span::attr::terResult, transToken(ter).c_str());
+ *  @endcode
+ *
+ *  @code
+ *      // Transactor::operator() uses span() with prefix + suffix:
+ *      auto span = SpanGuard::span(
+ *          TraceCategory::Transactions, seg::tx, tx_apply_span::op::transactor);
+ *      span.setAttribute(tx_apply_span::attr::stage, tx_apply_span::val::apply);
+ *  @endcode
+ */
+
+#include <xrpl/telemetry/SpanNames.h>
+
+namespace xrpl::telemetry::tx_apply_span {
+
+// ===== Span operation suffixes =============================================
+
+namespace op {
+/// "preflight" — stateless transaction checks (suffix form).
+inline constexpr auto preflight = makeStr("preflight");
+/// "preclaim" — ledger-aware checks before fee claim (suffix form).
+inline constexpr auto preclaim = makeStr("preclaim");
+/// "transactor" — the apply stage (suffix form, used with span()).
+inline constexpr auto transactor = makeStr("transactor");
+}  // namespace op
+
+// ===== Full span names (tx.<op>) ===========================================
+
+/// "tx.preflight" — full name for hashSpan() at the preflight stage.
+inline constexpr auto preflight = join(seg::tx, op::preflight);
+/// "tx.preclaim" — full name for hashSpan() at the preclaim stage.
+inline constexpr auto preclaim = join(seg::tx, op::preclaim);
+
+// ===== Attribute keys ======================================================
+
+namespace attr {
+/// "stage" — which apply-pipeline stage this span represents. Drives the
+/// collector spanmetrics `stage` dimension for per-stage RED metrics.
+inline constexpr auto stage = makeStr("stage");
+/// "tx_type" — transaction type name (e.g., "Payment", "OfferCreate").
+/// Matches tx_span::attr::txType so both share the spanmetrics dimension.
+inline constexpr auto txType = makeStr("tx_type");
+/// "ter_result" — engine result code after the stage (e.g., "tesSUCCESS").
+inline constexpr auto terResult = makeStr("ter_result");
+/// "applied" — whether the transaction was applied to the ledger (apply only).
+inline constexpr auto applied = makeStr("applied");
+}  // namespace attr
+
+// ===== Attribute values (stage names) ======================================
+
+namespace val {
+/// "preflight" — value of the stage attribute on tx.preflight.
+inline constexpr auto preflight = makeStr("preflight");
+/// "preclaim" — value of the stage attribute on tx.preclaim.
+inline constexpr auto preclaim = makeStr("preclaim");
+/// "apply" — value of the stage attribute on tx.transactor.
+inline constexpr auto apply = makeStr("apply");
+}  // namespace val
+
+}  // namespace xrpl::telemetry::tx_apply_span