Opentracing 1.6 API support

Implemented Clone(), ToTraceID(), ToSpanID(), extra variants of Log()
methods for SpanContext. Test cases for Clone(), ToTraceID(), and ToSpanID().

ci/WORKSPACE

@@ -5,7 +5,7 @@ load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
 git_repository(
     name = "io_opentracing_cpp",
     remote = "https://github.com/opentracing/opentracing-cpp",
-    commit = "ac50154a7713877f877981c33c3375003b6ebfe1",
+    commit = "597b0fa9507c854877b3efa9f4f20293a9e1ed30",
 )
 
 new_local_repository(

ci/build_plugin.sh

@@ -9,7 +9,7 @@ apt-get install --no-install-recommends --no-install-suggests -y \
                 git \
                 ca-certificates
 
-export OPENTRACING_VERSION=1.5.0
+export OPENTRACING_VERSION=1.6.0
 
 # Compile for a portable cpu architecture
 export CFLAGS="-march=x86-64"

ci/install_dependencies.sh

@@ -11,7 +11,7 @@ apt-get install --no-install-recommends --no-install-suggests -y \
 
 # Build OpenTracing
 cd /
-export OPENTRACING_VERSION=1.5.0
+export OPENTRACING_VERSION=1.6.0
 git clone -b v$OPENTRACING_VERSION https://github.com/opentracing/opentracing-cpp.git
 cd opentracing-cpp
 mkdir .build && cd .build

zipkin/include/zipkin/span_context.h

@@ -24,6 +24,7 @@ namespace zipkin {
  */
 struct AnnotationSet {
   AnnotationSet() : cs_(false), cr_(false), ss_(false), sr_(false) {}
+  AnnotationSet(const AnnotationSet &set) : cs_{set.cs_}, cr_{set.cr_}, ss_{set.ss_}, sr_{set.sr_} {}
   bool cs_ : 1;
   bool cr_ : 1;
   bool ss_ : 1;
@@ -58,6 +59,15 @@ class SpanContext {
       : trace_id_{trace_id}, id_{id}, parent_id_{parent_id}, flags_{flags},
         is_initialized_{true} {}
 
+  /**
+   * Copy constructor that creates a context object from the given SpanContext
+   * instance.
+   */
+  SpanContext(const SpanContext &span)
+      : trace_id_{span.trace_id_}, id_{span.id_}, parent_id_{span.parent_id_},
+        annotation_values_{span.annotation_values_}, flags_{span.flags_},
+        is_initialized_{span.is_initialized_} {}
+
   bool isSampled() const { return flags_ & zipkin::sampled_flag; }
 
   /**

zipkin_opentracing/src/opentracing.cc

@@ -50,6 +50,9 @@ class OtSpanContext : public ot::SpanContext {
 public:
   OtSpanContext() = default;
 
+  OtSpanContext(const OtSpanContext &span)
+      : span_context_{span.span_context_}, baggage_{span.baggage_} {}
+
   explicit OtSpanContext(zipkin::SpanContext &&span_context)
       : span_context_{std::move(span_context)} {}
 
@@ -69,6 +72,20 @@ class OtSpanContext : public ot::SpanContext {
     return *this;
   }
 
+  std::unique_ptr<SpanContext> Clone() const noexcept override try {
+    return std::unique_ptr<SpanContext> (new OtSpanContext(*this));
+  } catch (...) {
+    return nullptr;
+  }
+
+  std::string ToTraceID() const noexcept override {
+    return span_context_.traceIdAsHexString();
+  }
+
+  std::string ToSpanID() const noexcept override {
+    return span_context_.idAsHexString();
+  }
+
   void ForeachBaggageItem(
       std::function<bool(const std::string &, const std::string &)> f)
       const override {
@@ -258,6 +275,14 @@ class OtSpan : public ot::Span {
   void Log(std::initializer_list<std::pair<string_view, Value>>
                fields) noexcept override {}
 
+  void Log(
+    SystemTime timestamp,
+    std::initializer_list<std::pair<string_view, Value>> fields) noexcept override {}
+
+  void Log(
+    SystemTime timestamp,
+    const std::vector<std::pair<string_view, Value>>& fields) noexcept override {}
+
   const ot::SpanContext &context() const noexcept override {
     return span_context_;
   }

zipkin_opentracing/test/ot_tracer_test.cc

@@ -37,6 +37,20 @@ static bool IsChildOf(const zipkin::Span &a, const zipkin::Span &b) {
          a.traceId() == b.traceId();
 }
 
+class TextMapCarrier : public ot::TextMapWriter {
+public:
+  TextMapCarrier(std::unordered_map<std::string, std::string> &text_map)
+      : text_map_(text_map) {}
+
+  ot::expected<void> Set(ot::string_view key, ot::string_view value) const override {
+    text_map_[key] = value;
+    return {};
+  }
+
+private:
+  std::unordered_map<std::string, std::string> &text_map_;
+};
+
 TEST_CASE("ot_tracer") {
   auto reporter = new InMemoryReporter();
   ZipkinOtTracerOptions options;
@@ -167,4 +181,58 @@ TEST_CASE("ot_tracer") {
     span->Finish();
     CHECK(hasTag(reporter->top(), "abc", 123));
   }
+
+  SECTION("Get SpanContext and check that it is valid after Finish") {
+    auto span = tracer->StartSpan("a");
+    CHECK(span);
+    span->SetTag("abc", 123);
+    auto &ctx = span->context();
+    span->Finish();
+    auto trace_id = ctx.ToTraceID();
+    CHECK(trace_id != "");
+    auto span_id = ctx.ToSpanID();
+    CHECK(span_id != "");
+  }
+
+  SECTION("Check SpanContext.Clone() preserves attributes") {
+    auto span = tracer->StartSpan("a");
+    CHECK(span);
+    span->SetTag("abc", 123);
+    span->SetBaggageItem("a", "1");
+    auto &ctx = span->context();
+    span->Finish();
+    auto ctx2 = ctx.Clone();
+
+    CHECK(ctx.ToTraceID() == ctx2->ToTraceID());
+    CHECK(ctx.ToSpanID() == ctx2->ToSpanID());
+
+    std::unordered_map<std::string, std::string> items;
+    ctx.ForeachBaggageItem(
+        [&items] (const std::string& key, const std::string& value) {
+            items[key] = value;
+            return true;
+        }
+    );
+
+    std::unordered_map<std::string, std::string> items2;
+    ctx2->ForeachBaggageItem(
+        [&items2] (const std::string& key, const std::string& value) {
+            items2[key] = value;
+            return true;
+        }
+    );
+    CHECK(items == items2);
+
+    // Cross-check: serialize span context to a carrier
+    // and compare low-level representation
+    items.clear();
+    items2.clear();
+
+    TextMapCarrier carrier{items};
+    tracer->Inject(ctx, carrier);
+    TextMapCarrier carrier2{items2};
+    tracer->Inject(*ctx2, carrier2);
+
+    CHECK(items == items2);
+  }
 }