fixed #104 (#105)

Author: wuwen5

source/tracing_context_impl.cc

@@ -138,7 +138,8 @@ TracingContextImpl::TracingContextImpl(
     SpanContextExtensionPtr parent_ext_span_context, RandomGenerator& random)
     : parent_span_context_(std::move(parent_span_context)),
       parent_ext_span_context_(std::move(parent_ext_span_context)) {
-  segment_store_.set_traceid(random.uuid());
+  segment_store_.set_traceid(
+      parent_span_context_ ? parent_span_context_->traceId() : random.uuid());
   segment_store_.set_tracesegmentid(random.uuid());
   segment_store_.set_service(service_name);
   segment_store_.set_serviceinstance(instance_name);

test/tracing_context_test.cc

@@ -330,7 +330,7 @@ TEST_F(TracingContextTest, SW8CreateTest) {
   span2->endSpan();
 
   std::string expect_sw8(
-      "1-dXVpZA==-dXVpZA==-1-bWVzaA==-c2VydmljZV8w-c2FtcGxlMQ==-"
+      "1-MQ==-dXVpZA==-1-bWVzaA==-c2VydmljZV8w-c2FtcGxlMQ==-"
       "MTAuMC4wLjE6NDQz");
 
   EXPECT_EQ(expect_sw8, *sc.createSW8HeaderValue(target_address));
@@ -388,7 +388,7 @@ TEST_F(TracingContextTest, TraceLogTest) {
   TracingContextImpl sc(config_.service_name(), config_.instance_name(),
                         span_ctx_, span_ext_ctx_, random_);
   EXPECT_EQ(
-      "test\", \"SW_CTX\": [\"mesh\",\"service_0\",\"uuid\",\"uuid\",\"-1\"]}",
+      "test\", \"SW_CTX\": [\"mesh\",\"service_0\",\"1\",\"uuid\",\"-1\"]}",
       sc.logMessage("test"));
 }