Add Jaeger propagator

CHANGELOG.md

@@ -16,6 +16,7 @@ Increment the:
 ## [Unreleased]
 
 * [EXPORTER] Added Zipkin Exporter. ([#471](https:/open-telemetry/opentelemetry-cpp/pull/471))
+* [API] Added Jaeger propagator. ([#599](https:/open-telemetry/opentelemetry-cpp/pull/599))
 * [PROPAGATOR] Added Composite Propagator ([#597](https:/open-telemetry/opentelemetry-cpp/pull/597))
 
 ## [0.2.0] 2021-03-02

api/include/opentelemetry/context/context.h

@@ -60,7 +60,7 @@ class Context
  }
 
  // Returns the value associated with the passed in key.
- context::ContextValue GetValue(const nostd::string_view key) noexcept
+ context::ContextValue GetValue(const nostd::string_view key) const noexcept
  {
  for (DataList *data = head_.get(); data != nullptr; data = data->next_.get())
  {

api/include/opentelemetry/trace/propagation/b3_propagator.h

@@ -4,6 +4,7 @@
 #include <iostream>
 #include <map>
 #include <string>
+#include "detail/context.h"
 #include "opentelemetry/common/key_value_iterable.h"
 #include "opentelemetry/context/context.h"
 #include "opentelemetry/nostd/shared_ptr.h"
@@ -62,17 +63,6 @@ class B3PropagatorExtractor : public TextMapPropagator<T>
  return context.SetValue(kSpanKey, sp);
  }
 
- static SpanContext GetCurrentSpan(const context::Context &context)
- {
- context::Context ctx(context);
- context::ContextValue span = ctx.GetValue(kSpanKey);
- if (nostd::holds_alternative<nostd::shared_ptr<Span>>(span))
- {
- return nostd::get<nostd::shared_ptr<Span>>(span).get()->GetContext();
- }
- return SpanContext::GetInvalid();
- }
-
  static TraceId GenerateTraceIdFromString(nostd::string_view trace_id)
  {
  uint8_t buf[kTraceIdHexStrLength / 2];
@@ -213,7 +203,7 @@ class B3Propagator : public B3PropagatorExtractor<T>
  // Sets the context for a HTTP header carrier with self defined rules.
  void Inject(Setter setter, T &carrier, const context::Context &context) noexcept override
  {
- SpanContext span_context = B3PropagatorExtractor<T>::GetCurrentSpan(context);
+ SpanContext span_context = detail::GetCurrentSpan(context);
  if (!span_context.IsValid())
  {
  return;
@@ -251,7 +241,7 @@ class B3PropagatorMultiHeader : public B3PropagatorExtractor<T>
  nostd::string_view trace_description);
  void Inject(Setter setter, T &carrier, const context::Context &context) noexcept override
  {
- SpanContext span_context = B3PropagatorExtractor<T>::GetCurrentSpan(context);
+ SpanContext span_context = detail::GetCurrentSpan(context);
  if (!span_context.IsValid())
  {
  return;

api/include/opentelemetry/trace/propagation/detail/context.h

@@ -0,0 +1,26 @@
+#pragma once
+#include "opentelemetry/context/context.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace trace
+{
+namespace propagation
+{
+namespace detail
+{
+
+trace::SpanContext GetCurrentSpan(const context::Context &context)
+{
+ context::ContextValue span = context.GetValue(trace::kSpanKey);
+ if (nostd::holds_alternative<nostd::shared_ptr<trace::Span>>(span))
+ {
+ return nostd::get<nostd::shared_ptr<trace::Span>>(span).get()->GetContext();
+ }
+
+ return trace::SpanContext::GetInvalid();
+}
+
+} // namespace detail
+} // namespace propagation
+} // namespace trace
+OPENTELEMETRY_END_NAMESPACE

api/include/opentelemetry/trace/propagation/detail/hex.h

@@ -0,0 +1,74 @@
+#pragma once
+
+#include "opentelemetry/nostd/string_view.h"
+
+#include <algorithm>
+#include <cstring>
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace trace
+{
+namespace propagation
+{
+namespace detail
+{
+
+constexpr int8_t kHexDigits[256] = {
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, -1, 10, 11, 12, 13, 14, 15, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+ -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
+};
+
+inline int8_t HexToInt(char c)
+{
+ return kHexDigits[uint8_t(c)];
+}
+
+bool IsValidHex(nostd::string_view s)
+{
+ return std::all_of(s.begin(), s.end(), [](char c) { return HexToInt(c) != -1; });
+}
+
+/**
+ * Converts a hexadecimal to binary format if the hex string will fit the buffer.
+ * Smaller hex strings are left padded with zeroes.
+ */
+bool HexToBinary(nostd::string_view hex, uint8_t *buffer, size_t buffer_size)
+{
+ if (hex.size() > buffer_size * 2)
+ {
+ return false;
+ }
+
+ std::memset(buffer, 0, buffer_size);
+
+ int64_t hex_size = int64_t(hex.size());
+ int64_t buffer_pos = int64_t(buffer_size) - (hex_size + 1) / 2;
+ int64_t last_hex_pos = hex_size - 1;
+
+ int64_t i = 0;
+ for (; i < last_hex_pos; i += 2)
+ {
+ buffer[buffer_pos++] = (HexToInt(hex[i]) << 4) | HexToInt(hex[i + 1]);
+ }
+
+ if (i == last_hex_pos)
+ {
+ buffer[buffer_pos] = HexToInt(hex[i]);
+ }
+
+ return true;
+}
+
+} // namespace detail
+} // namespace propagation
+} // namespace trace
+OPENTELEMETRY_END_NAMESPACE

api/include/opentelemetry/trace/propagation/detail/string.h

@@ -0,0 +1,54 @@
+#pragma once
+
+#include "opentelemetry/nostd/string_view.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace trace
+{
+namespace propagation
+{
+namespace detail
+{
+
+/**
+ * Splits a string by separator, up to given buffer count words.
+ * Returns the amount of words the input was split into.
+ */
+size_t SplitString(nostd::string_view s, char separator, nostd::string_view *results, size_t count)
+{
+ if (count == 0)
+ {
+ return count;
+ }
+
+ size_t filled = 0;
+ size_t token_start = 0;
+ for (size_t i = 0; i < s.size(); i++)
+ {
+ if (s[i] != separator)
+ {
+ continue;
+ }
+
+ results[filled++] = s.substr(token_start, i - token_start);
+
+ if (filled == count)
+ {
+ return count;
+ }
+
+ token_start = i + 1;
+ }
+
+ if (filled < count)
+ {
+ results[filled++] = s.substr(token_start);
+ }
+
+ return filled;
+}
+
+} // namespace detail
+} // namespace propagation
+} // namespace trace
+OPENTELEMETRY_END_NAMESPACE

api/include/opentelemetry/trace/propagation/http_trace_context.h

@@ -16,6 +16,7 @@
 #include <iostream>
 #include <map>
 #include <string>
+#include "detail/context.h"
 #include "opentelemetry/common/key_value_iterable.h"
 #include "opentelemetry/context/context.h"
 #include "opentelemetry/nostd/shared_ptr.h"
@@ -65,7 +66,7 @@ class HttpTraceContext : public TextMapPropagator<T>
 
  void Inject(Setter setter, T &carrier, const context::Context &context) noexcept override
  {
- SpanContext span_context = GetCurrentSpan(context);
+ SpanContext span_context = detail::GetCurrentSpan(context);
  if (!span_context.IsValid())
  {
  return;
@@ -82,17 +83,6 @@ class HttpTraceContext : public TextMapPropagator<T>
  return context.SetValue(kSpanKey, sp);
  }
 
- static SpanContext GetCurrentSpan(const context::Context &context)
- {
- context::Context ctx(context);
- context::ContextValue span = ctx.GetValue(kSpanKey);
- if (nostd::holds_alternative<nostd::shared_ptr<Span>>(span))
- {
- return nostd::get<nostd::shared_ptr<Span>>(span).get()->GetContext();
- }
- return SpanContext::GetInvalid();
- }
-
  static TraceId GenerateTraceIdFromString(nostd::string_view trace_id)
  {
  int trace_id_len = kHeaderElementLengths[1];

api/include/opentelemetry/trace/propagation/jaeger.h

@@ -0,0 +1,131 @@
+#pragma once
+
+// Copyright 2021, OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "detail/context.h"
+#include "detail/hex.h"
+#include "detail/string.h"
+#include "opentelemetry/trace/default_span.h"
+#include "opentelemetry/trace/propagation/text_map_propagator.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace trace
+{
+namespace propagation
+{
+
+static const nostd::string_view kTraceHeader = "uber-trace-id";
+
+template <typename T>
+class JaegerPropagator : public TextMapPropagator<T>
+{
+public:
+ using Getter = nostd::string_view (*)(const T &carrier, nostd::string_view trace_type);
+
+ using Setter = void (*)(T &carrier,
+ nostd::string_view trace_type,
+ nostd::string_view trace_description);
+
+ void Inject(Setter setter, T &carrier, const context::Context &context) noexcept override
+ {
+ SpanContext span_context = detail::GetCurrentSpan(context);
+ if (!span_context.IsValid())
+ {
+ return;
+ }
+
+ const size_t trace_id_length = 32;
+ const size_t span_id_length = 16;
+
+ // trace-id(32):span-id(16):0:debug(2)
+ char trace_identity[trace_id_length + span_id_length + 6];
+ span_context.trace_id().ToLowerBase16({&trace_identity[0], trace_id_length});
+ trace_identity[trace_id_length] = ':';
+ span_context.span_id().ToLowerBase16({&trace_identity[trace_id_length + 1], span_id_length});
+ trace_identity[trace_id_length + span_id_length + 1] = ':';
+ trace_identity[trace_id_length + span_id_length + 2] = '0';
+ trace_identity[trace_id_length + span_id_length + 3] = ':';
+ trace_identity[trace_id_length + span_id_length + 4] = '0';
+ trace_identity[trace_id_length + span_id_length + 5] = span_context.IsSampled() ? '1' : '0';
+
+ setter(carrier, kTraceHeader, nostd::string_view(trace_identity, sizeof(trace_identity)));
+ }
+
+ context::Context Extract(Getter getter,
+ const T &carrier,
+ context::Context &context) noexcept override
+ {
+ SpanContext span_context = ExtractImpl(getter, carrier);
+ nostd::shared_ptr<Span> sp{new DefaultSpan(span_context)};
+ return context.SetValue(kSpanKey, sp);
+ }
+
+private:
+ static constexpr uint8_t kIsSampled = 0x01;
+
+ static TraceFlags GetTraceFlags(uint8_t jaeger_flags)
+ {
+ uint8_t sampled = jaeger_flags & kIsSampled;
+ return TraceFlags(sampled);
+ }
+
+ static SpanContext ExtractImpl(Getter getter, const T &carrier)
+ {
+ nostd::string_view trace_identity = getter(carrier, kTraceHeader);
+
+ const size_t trace_field_count = 4;
+ nostd::string_view trace_fields[trace_field_count];
+
+ if (detail::SplitString(trace_identity, ':', trace_fields, trace_field_count) !=
+ trace_field_count)
+ {
+ return SpanContext::GetInvalid();
+ }
+
+ nostd::string_view trace_id_hex = trace_fields[0];
+ nostd::string_view span_id_hex = trace_fields[1];
+ nostd::string_view flags_hex = trace_fields[3];
+
+ if (!detail::IsValidHex(trace_id_hex) || !detail::IsValidHex(span_id_hex) ||
+ !detail::IsValidHex(flags_hex))
+ {
+ return SpanContext::GetInvalid();
+ }
+
+ uint8_t trace_id[16];
+ if (!detail::HexToBinary(trace_id_hex, trace_id, sizeof(trace_id)))
+ {
+ return SpanContext::GetInvalid();
+ }
+
+ uint8_t span_id[8];
+ if (!detail::HexToBinary(span_id_hex, span_id, sizeof(span_id)))
+ {
+ return SpanContext::GetInvalid();
+ }
+
+ uint8_t flags;
+ if (!detail::HexToBinary(flags_hex, &flags, sizeof(flags)))
+ {
+ return SpanContext::GetInvalid();
+ }
+
+ return SpanContext(TraceId(trace_id), SpanId(span_id), GetTraceFlags(flags), true);
+ }
+};
+
+} // namespace propagation
+} // namespace trace
+OPENTELEMETRY_END_NAMESPACE