Add interfaces in DTTracer to serialize and deserialize span

Signed-off-by: Emelia Lei <[email protected]>

Author: emelialei88

src/groups/bmq/bmqpi/bmqpi_dttracer.h

@@ -32,6 +32,7 @@
 // BDE
 #include <bsl_memory.h>
 #include <bsl_string_view.h>
+#include <bsl_vector.h>
 
 namespace BloombergLP {
 namespace bmqpi {
@@ -56,6 +57,23 @@ class DTTracer {
         const bsl::shared_ptr<DTSpan>& parent,
         const bsl::string_view&        operation,
         const DTSpan::Baggage&         baggage = DTSpan::Baggage()) const = 0;
+
+    /// Serialize the underlying context for a specified `DTSpan` and return
+    /// the bit stream as `out`.  Return 0 on success, or a non-zero error code
+    /// on error.
+    virtual int serializeSpan(bsl::vector<unsigned char>*    out,
+                              const bsl::shared_ptr<DTSpan>& dtSpan) const = 0;
+
+    /// Deserialize the specified bit stream `in` into a span context.
+    /// Create a child span and pass into `out` based on the deserialized
+    /// parent span context, the given `operation`, and an optional key-value
+    /// tags `baggage`.  Return 0 on success, or a non-zero error code on
+    /// error.
+    virtual int deserializeAndCreateChildSpan(
+        bsl::shared_ptr<DTSpan>*          out,
+        const bsl::vector<unsigned char>& in,
+        const bsl::string_view&           operation,
+        const DTSpan::Baggage& baggage = DTSpan::Baggage()) const = 0;
 };
 
 }  // close package namespace

src/groups/bmq/bmqpi/bmqpi_dttracer.t.cpp

@@ -35,6 +35,17 @@ struct DTTracerTestImp : public bsls::ProtocolTestImp<bmqpi::DTTracer> {
         const bsl::shared_ptr<bmqpi::DTSpan>& parent,
         const bsl::string_view&               operation,
         const bmqpi::DTSpan::Baggage& baggage) const BSLS_KEYWORD_OVERRIDE;
+
+    virtual int serializeSpan(bsl::vector<unsigned char>*           out,
+                              const bsl::shared_ptr<bmqpi::DTSpan>& dtSpan)
+        const BSLS_KEYWORD_OVERRIDE;
+
+    virtual int deserializeAndCreateChildSpan(
+        bsl::shared_ptr<bmqpi::DTSpan>*   out,
+        const bsl::vector<unsigned char>& in,
+        const bsl::string_view&           operation,
+        const bmqpi::DTSpan::Baggage& baggage = bmqpi::DTSpan::Baggage()) const
+        BSLS_KEYWORD_OVERRIDE;
 };
 
 // Define one of DTTracerTestImp methods out-of-line, to instruct the
@@ -47,6 +58,21 @@ DTTracerTestImp::createChildSpan(const bsl::shared_ptr<bmqpi::DTSpan>&,
     return markDone();
 }
 
+int DTTracerTestImp::serializeSpan(bsl::vector<unsigned char>*,
+                                   const bsl::shared_ptr<bmqpi::DTSpan>&) const
+{
+    return markDone();
+}
+
+int DTTracerTestImp::deserializeAndCreateChildSpan(
+    bsl::shared_ptr<bmqpi::DTSpan>*,
+    const bsl::vector<unsigned char>&,
+    const bsl::string_view&,
+    const bmqpi::DTSpan::Baggage&) const
+{
+    return markDone();
+}
+
 // ============================================================================
 //                                    TESTS
 // ============================================================================
@@ -100,8 +126,13 @@ static void test1_breathingTest()
     BMQTST_ASSERT(tracer.testVirtualDestructor());
 
     PV("Verify that all methods are public and virtual");
-    bmqpi::DTSpan::Baggage empty;
+    bmqpi::DTSpan::Baggage     empty;
+    bsl::vector<unsigned char> emptyVec;
     BSLS_PROTOCOLTEST_ASSERT(tracer, createChildSpan(NULL, "", empty));
+    BSLS_PROTOCOLTEST_ASSERT(tracer, serializeSpan(NULL, NULL));
+    BSLS_PROTOCOLTEST_ASSERT(
+        tracer,
+        deserializeAndCreateChildSpan(NULL, emptyVec, "", empty));
 }
 
 // ============================================================================