KIKIMR-20533 Implemented conversion from OTEL header to traceId (#607)

* KIKIMR-20533 Implemented conversion from OTEL header to traceId

Author: domwst

ydb/library/actors/wilson/wilson_trace.cpp

@@ -1,4 +1,67 @@
 #include "wilson_trace.h"
 
+#include <util/generic/algorithm.h>
+#include <util/string/hex.h>
+
 namespace NWilson {
+    TTraceId TTraceId::FromTraceparentHeader(const TStringBuf header) {
+        constexpr size_t versionChars = 2; // Only version 0 is supported
+        constexpr size_t versionStart = 0;
+
+        constexpr size_t traceIdChars = 32;
+        constexpr size_t traceIdStart = versionStart + versionChars + 1;
+        static_assert(traceIdChars == TTraceId::GetTraceIdSize() * 2);
+
+        constexpr size_t parentSpanIdChars = 16;
+        constexpr size_t parentSpanIdStart = traceIdStart + traceIdChars + 1;
+        static_assert(parentSpanIdChars == TTraceId::GetSpanIdSize() * 2);
+
+        constexpr size_t traceFlagsChars = 2;
+        constexpr size_t traceFlagsStart = parentSpanIdStart + parentSpanIdChars + 1;
+
+        constexpr size_t expectedHeaderSize =
+            versionChars + traceIdChars + parentSpanIdChars + traceFlagsChars + 3;
+
+        if (header.Size() != expectedHeaderSize) {
+            return {};
+        }
+
+        auto isHex = [](char c) {
+            return (c >= '0' && c <= '9') || (c >= 'A' && c <= 'F') || (c >= 'a' && c <= 'f');
+        };
+
+        if (!AllOf(header.substr(versionStart, versionChars), isHex) ||
+                !AllOf(header.substr(traceIdStart, traceIdChars), isHex) ||
+                !AllOf(header.substr(parentSpanIdStart, parentSpanIdChars), isHex) ||
+                !AllOf(header.substr(traceFlagsStart, traceFlagsChars), isHex)) {
+            return {};
+        }
+
+        if (header[traceIdStart - 1] != '-' || header[parentSpanIdStart - 1] != '-' || header[traceIdChars - 1] != '-') {
+            return {};
+        }
+
+        ui8 version;
+        HexDecode(header.Data(), versionChars, &version);
+        if (version != 0) {
+            return {};
+        }
+
+        TTrace traceId;
+        ui64 spanId;
+        static_assert(traceIdChars == 2 * sizeof(traceId));
+        static_assert(parentSpanIdChars == 2 * sizeof(spanId));
+        HexDecode(header.Data() + traceIdStart, traceIdChars, &traceId);
+        HexDecode(header.Data() + parentSpanIdStart, parentSpanIdChars, &spanId);
+
+        if ((traceId[0] == 0 && traceId[1] == 0) || spanId == 0) {
+            return {};
+        }
+
+        return TTraceId(traceId, spanId, 15, Max<ui32>());
+    }
+
+    TString TTraceId::GetHexTraceId() const {
+        return HexEncode(GetTraceIdPtr(), GetTraceIdSize());
+    }
 }

ydb/library/actors/wilson/wilson_trace.h

@@ -5,11 +5,9 @@
 
 #include <library/cpp/string_utils/base64/base64.h>
 
-#include <util/stream/output.h>
 #include <util/random/random.h>
 #include <util/random/fast.h>
-
-#include <util/string/hex.h>
+#include <util/stream/output.h>
 #include <util/string/printf.h>
 
 #include <array>
@@ -186,6 +184,8 @@ namespace NWilson {
             return TTraceId();
         }
 
+        static TTraceId FromTraceparentHeader(const TStringBuf header);
+
         TTraceId Span(ui8 verbosity) const {
             Validate();
             if (!*this || !TimeToLive) {
@@ -223,9 +223,7 @@ namespace NWilson {
         const void *GetSpanIdPtr() const { return &SpanId; }
         static constexpr size_t GetSpanIdSize() { return sizeof(ui64); }
 
-        TString GetHexTraceId() const {
-            return HexEncode(GetTraceIdPtr(), GetTraceIdSize());
-        }
+        TString GetHexTraceId() const;
 
         void Validate() const {
             Y_DEBUG_ABORT_UNLESS(*this || !SpanId);