Added ability to send the client job heartbeat calls to server. (#2016)

* Added ability to send the client job heartbeat calls to server.

* codestyle fixes.

* Changed to use aux_message for sending the client job heartbeat calls.

* Made the thread daemon=true.

nvflare/apis/fl_constant.py

@@ -162,6 +162,7 @@ class ReservedTopic(object):
     END_RUN = "__end_run__"
     ABORT_ASK = "__abort_task__"
     AUX_COMMAND = "__aux_command__"
+    JOB_HEART_BEAT = "__job_heartbeat__"
 
 
 class AdminCommandNames(object):

nvflare/private/fed/client/client_runner.py

@@ -22,6 +22,7 @@
 from nvflare.apis.shareable import Shareable, make_reply
 from nvflare.apis.signal import Signal
 from nvflare.apis.utils.fl_context_utils import add_job_audit_event
+from nvflare.fuel.f3.cellnet.fqcn import FQCN
 from nvflare.private.defs import SpecialTaskName, TaskConstant
 from nvflare.private.fed.client.client_engine_executor_spec import ClientEngineExecutorSpec, TaskAssignment
 from nvflare.private.privacy_manager import Scope
@@ -392,6 +393,9 @@ def _check_stop_conditions(self, fl_ctx: FLContext) -> bool:
         return False
 
     def _try_run(self):
+        heartbeat_thread = threading.Thread(target=self.send_job_heartbeat, args=[], daemon=True)
+        heartbeat_thread.start()
+
         while not self.asked_to_stop:
             with self.engine.new_context() as fl_ctx:
                 if self._check_stop_conditions(fl_ctx):
@@ -404,6 +408,25 @@ def _try_run(self):
 
                 time.sleep(task_fetch_interval)
 
+    def send_job_heartbeat(self, interval=30.0):
+        wait_times = int(interval / 2)
+        request = Shareable()
+        while not self.asked_to_stop:
+            with self.engine.new_context() as fl_ctx:
+                self.engine.send_aux_request(
+                    targets=[FQCN.ROOT_SERVER],
+                    topic=ReservedTopic.JOB_HEART_BEAT,
+                    request=request,
+                    timeout=0,
+                    fl_ctx=fl_ctx,
+                    optional=True,
+                )
+
+                for i in range(wait_times):
+                    time.sleep(2)
+                    if self.asked_to_stop:
+                        break
+
     def fetch_and_run_one_task(self, fl_ctx) -> (float, bool):
         """Fetches and runs a task.
 

nvflare/private/fed/server/server_runner.py

@@ -99,6 +99,13 @@ def __init__(self, config: ServerRunnerConfig, job_id: str, engine: ServerEngine
         self.status = "init"
         self.turn_to_cold = False
 
+        self._register_aux_message_handler(engine)
+
+    def _register_aux_message_handler(self, engine):
+        engine.register_aux_message_handler(
+            topic=ReservedTopic.JOB_HEART_BEAT, message_handle_func=self._handle_job_heartbeat
+        )
+
     def _execute_run(self):
         while self.current_wf_index < len(self.config.workflows):
             wf = self.config.workflows[self.current_wf_index]
@@ -489,6 +496,10 @@ def process_submission(self, client: Client, task_name: str, task_id: str, resul
                     "Error processing client result by {}: {}".format(self.current_wf.id, secure_format_exception(e)),
                 )
 
+    def _handle_job_heartbeat(self, topic: str, request: Shareable, fl_ctx: FLContext) -> Shareable:
+        self.log_info(fl_ctx, "received client job_heartbeat aux request")
+        return make_reply(ReturnCode.OK)
+
     def abort(self, fl_ctx: FLContext, turn_to_cold: bool = False):
         self.status = "done"
         self.abort_signal.trigger(value=True)