make previous op's name visible to current op, we assume DAG is sequential in...

make previous op's name visible to current op, we assume DAG is sequential in this case, will refine later

core/predictor/framework/dag_view.cpp

@@ -45,6 +45,8 @@ int DagView::init(Dag* dag, const std::string& service_name) {
                  << "at:" << si;
       return ERR_MEM_ALLOC_FAILURE;
     }
+    VLOG(2) << "stage[" << si << "] name: " <<  stage->full_name;
+    VLOG(2) << "stage[" << si << "] node size: " << stage->nodes.size();
     vstage->full_name = service_name + NAME_DELIMITER + stage->full_name;
     uint32_t node_size = stage->nodes.size();
     // create tls view node
@@ -63,16 +65,30 @@ int DagView::init(Dag* dag, const std::string& service_name) {
       }
 
       // initialize a TLS op object
+      VLOG(2) << "dag view initialized: \n"
+              << "node id: " << node->id << "\n"
+              << "node name: " << node->name << "\n"
+              << "node type: " << node->type;
       if (op->init(_bus, dag, node->id, node->name, node->type, node->conf) !=
           0) {
         LOG(WARNING) << "Failed init op, type:" << node->type;
         return ERR_INTERNAL_FAILURE;
       }
+      
       op->set_full_name(service_name + NAME_DELIMITER + node->full_name);
       vnode->conf = node;
       vnode->op = op;
       vstage->nodes.push_back(vnode);
     }
+    // TODO(guru4elephant): this seems buggy, please review later
+    if (si > 0) {
+      VLOG(2) << "set op pre name: \n"
+              << "current op name: " << vstage->nodes.back()->op->op_name()
+              << " previous op name: "
+              << _view[si-1]->nodes.back()->op->op_name();
+      vstage->nodes.back()->op->set_pre_node_name(
+          _view[si-1]->nodes.back()->op->op_name());
+    }
     _view.push_back(vstage);
   }
 

core/predictor/op/op.cpp

@@ -127,6 +127,7 @@ int Op::process(bool debug) {
           return -1;
       }
   }*/
+
   if (debug && _timer) {
     _timer->check("depend");
   }

core/predictor/op/op.h

@@ -128,10 +128,18 @@ class Op {
 
   const char* name() const;
 
+  const std::string& op_name() const { return _name; }
+
   const std::string& full_name() const { return _full_name; }
 
+  const std::string& pre_name() const { return _pre_node_name; }
+
   void set_full_name(const std::string full_name) { _full_name = full_name; }
 
+  void set_pre_node_name(const std::string pre_name) {
+    _pre_node_name = pre_name;
+  }
+
   const std::string& type() const;
 
   uint32_t id() const;
@@ -181,6 +189,7 @@ class Op {
   Bus* _bus;
   Dag* _dag;
   uint32_t _id;
+  std::string _pre_node_name;  // only for sequential execution
   std::string _name;
   std::string _full_name;  // service_workflow_stageindex_opname
   std::string _type;