HPCC-33145: Optimize ESP server span creation

esp/bindings/http/platform/httpservice.cpp

@@ -351,6 +351,44 @@ int CEspHttpServer::processRequest()
         m_request->getEspPathInfo(stype, &pathEx, &serviceName, &methodName, false);
         ESPLOG(LogNormal,"sub service type: %s. parm: %s", getSubServiceDesc(stype), m_request->queryParamStr());
 
+        // getEspPathInfo provides all information needed to decide if the request should be
+        // traced. Create a server span, if needed, before proceding with request processing
+        // so maximize the amount of request processing that can be traced. Specifically, user
+        // authentication and authorization may generate trace output.
+        bool wantTracing = true;
+        if (!queryTraceManager().isTracingEnabled())
+            wantTracing = false;
+        else if (streq(method, GET_METHOD))
+        {
+            if (sub_serv_root == stype)
+                wantTracing = false;
+            else if (strieq(serviceName, "esp"))
+            {
+                wantTracing = !(methodName.isEmpty() ||
+                    strieq(methodName, "files") ||
+                    strieq(methodName, "xslt") ||
+                    strieq(methodName, "frame") ||
+                    strieq(methodName, "titlebar") ||
+                    strieq(methodName, "nav") ||
+                    strieq(methodName, "navdata") ||
+                    strieq(methodName, "navmenuevent") ||
+                    strieq(methodName, "soapreq"));
+            }
+        }
+        else if (!m_apport)
+            wantTracing = false;
+        Owned<ISpan> serverSpan;
+        if (wantTracing)
+        {
+            // The context will be destroyed when this request is destroyed. So initialise a
+            // SpanScope in the context to ensure the span is also terminated at the same time.
+            serverSpan.setown(m_request->createServerSpan(serviceName, methodName));
+            ctx->setRequestSpan(serverSpan);
+        }
+        else
+            serverSpan.setown(getNullSpan());
+        ActiveSpanScope serverSpanScope(serverSpan);
+
         m_request->updateContext();
         ctx->setServiceName(serviceName.str());
         ctx->setHTTPMethod(method.str());
@@ -500,11 +538,6 @@ int CEspHttpServer::processRequest()
                 return 0;
             }
 
-            //The context will be destroyed when this request is destroyed. So initialise a SpanScope in the context to
-            //ensure the span is also terminated at the same time.
-            Owned<ISpan> serverSpan = m_request->createServerSpan(serviceName, methodName);
-            ctx->setRequestSpan(serverSpan);
-
             if (thebinding!=NULL)
             {
                 if(stricmp(method.str(), POST_METHOD)==0)

esp/bindings/http/platform/httptransport.cpp

@@ -1924,7 +1924,7 @@ ISpan * CHttpRequest::createServerSpan(const char * serviceName, const char * me
         spanName.append("/").append(methodName);
     spanName.toLowerCase();
     Owned<IProperties> httpHeaders = getHeadersAsProperties(m_headers);
-    return queryTraceManager().createServerSpan(spanName, httpHeaders, SpanFlags::EnsureGlobalId);
+    return queryTraceManager().createServerSpan(spanName, httpHeaders, &m_receivedAt, SpanFlags::EnsureGlobalId);
 }
 
 void CHttpRequest::annotateSpan(const char * key, const char * value)
@@ -2089,6 +2089,7 @@ int CHttpRequest::processHeaders(IMultiException *me)
     char oneline[MAX_HTTP_HEADER_LEN + 2];
 
     int lenread = m_bufferedsocket->readline(oneline, MAX_HTTP_HEADER_LEN + 1, me);
+    m_receivedAt.now(); // use receipt of a first loe as the start time for a server span
     if(lenread <= 0) //special case client connected and disconnected, load balancer ping?
         return -1;
     else if (lenread > MAX_HTTP_HEADER_LEN)

esp/bindings/http/platform/httptransport.ipp

@@ -329,6 +329,7 @@ const char* getSubServiceDesc(sub_service stype);
 class esp_http_decl CHttpRequest : public CHttpMessage
 {
 private:
+    SpanTimeStamp m_receivedAt;
     StringAttr    m_httpMethod;
     StringAttr    m_espServiceName;
     StringAttr    m_espMethodName;

esp/platform/espcontext.cpp

@@ -89,7 +89,7 @@ class CEspContext : public CInterface, implements IEspContext
     Owned<IEspSecureContextEx> m_secureContext;
 
     StringAttr   m_transactionID;
-    OwnedActiveSpanScope m_requestSpan;    // When the context is destroy the span will end.
+    OwnedSpanLifetime m_requestSpan;    // When the context is destroy the span will end.
     IHttpMessage* m_request;
 
 public: