Set auto config hint for empty polls (#6611)

* Set auto config hint for empty polls
* Get auto config hint enabled flag from matching engine config

service/matching/handler/engine.go

@@ -539,6 +539,7 @@ pollLoop:
 		if err != nil {
 			return nil, fmt.Errorf("couldn't load tasklist namanger: %w", err)
 		}
+		startT := time.Now() // Record the start time
 		task, err := tlMgr.GetTask(pollerCtx, nil)
 		if err != nil {
 			// TODO: Is empty poll the best reply for errPumpClosed?
@@ -561,9 +562,14 @@ pollLoop:
 						"RequestForwardedFrom": req.GetForwardedFrom(),
 					},
 				})
+				domainName, _ := e.domainCache.GetDomainName(domainID)
 				return &types.MatchingPollForDecisionTaskResponse{
 					PartitionConfig:   tlMgr.TaskListPartitionConfig(),
 					LoadBalancerHints: tlMgr.LoadBalancerHints(),
+					AutoConfigHint: &types.AutoConfigHint{
+						EnableAutoConfig:   e.config.EnableClientAutoConfig(domainName, taskListName, persistence.TaskListTypeDecision),
+						PollerWaitTimeInMs: time.Since(startT).Milliseconds(),
+					},
 				}, nil
 			}
 			return nil, fmt.Errorf("couldn't get task: %w", err)
@@ -722,13 +728,19 @@ pollLoop:
 		if err != nil {
 			return nil, fmt.Errorf("couldn't load tasklist namanger: %w", err)
 		}
+		startT := time.Now() // Record the start time
 		task, err := tlMgr.GetTask(pollerCtx, maxDispatch)
 		if err != nil {
 			// TODO: Is empty poll the best reply for errPumpClosed?
 			if errors.Is(err, tasklist.ErrNoTasks) || errors.Is(err, errPumpClosed) {
+				domainName, _ := e.domainCache.GetDomainName(domainID)
 				return &types.MatchingPollForActivityTaskResponse{
 					PartitionConfig:   tlMgr.TaskListPartitionConfig(),
 					LoadBalancerHints: tlMgr.LoadBalancerHints(),
+					AutoConfigHint: &types.AutoConfigHint{
+						EnableAutoConfig:   e.config.EnableClientAutoConfig(domainName, taskListName, persistence.TaskListTypeDecision),
+						PollerWaitTimeInMs: time.Since(startT).Milliseconds(),
+					},
 				}, nil
 			}
 			e.logger.Error("Received unexpected err while getting task",

service/matching/handler/engine_integration_test.go

@@ -311,6 +311,8 @@ func (s *matchingEngineSuite) PollForDecisionTasksResultTest() {
 	}
 	resp, err := pollTask(s.matchingEngine, s.handlerContext, pollReq)
 	s.NoError(err)
+	s.NotNil(resp.AutoConfigHint)
+	resp.AutoConfigHint = nil
 	s.Equal(&pollTaskResponse{}, resp)
 	// add task to sticky tasklist again, this time it should pass
 	_, err = addTask(s.matchingEngine, s.handlerContext, addRequest)
@@ -363,6 +365,8 @@ func (s *matchingEngineSuite) PollForTasksEmptyResultTest(callContext context.Co
 			Identity:   identity,
 		}
 		pollResp, err := pollTask(s.matchingEngine, s.handlerContext, pollReq)
+		s.NotNil(pollResp.AutoConfigHint)
+		pollResp.AutoConfigHint = nil // poller wait time is not a fixed value, exclude it from comparison
 		s.NoError(err)
 		s.Equal(&pollTaskResponse{}, pollResp)
 
@@ -952,6 +956,8 @@ func (s *matchingEngineSuite) PollWithExpiredContext(taskType int) {
 	s.handlerContext.Context = ctx
 	resp, err := pollTask(s.matchingEngine, s.handlerContext, pollReq)
 	s.Nil(err)
+	s.NotNil(resp.AutoConfigHint)
+	resp.AutoConfigHint = nil
 	s.Equal(&pollTaskResponse{}, resp)
 }
 
@@ -1134,6 +1140,8 @@ func (s *matchingEngineSuite) UnloadTasklistOnIsolationConfigChange(taskType int
 	}
 	result, err := pollTask(s.matchingEngine, s.handlerContext, pollReq)
 	s.NoError(err)
+	s.NotNil(result.AutoConfigHint)
+	result.AutoConfigHint = nil
 	s.Equal(&pollTaskResponse{}, result)
 
 	result, err = pollTask(s.matchingEngine, s.handlerContext, pollReq)
@@ -1644,6 +1652,7 @@ func pollTask(engine *matchingEngineImpl, hCtx *handlerContext, request *pollTas
 			WorkflowType:                    resp.WorkflowType,
 			WorkflowDomain:                  resp.WorkflowDomain,
 			Header:                          resp.Header,
+			AutoConfigHint:                  resp.AutoConfigHint,
 		}, nil
 	}
 	resp, err := engine.PollForDecisionTask(hCtx, &types.MatchingPollForDecisionTaskRequest{