Don't export to collections for all workers with unsupported distrib training (#263)

Author: vandanavk

smdebug/core/hook.py

@@ -436,12 +436,13 @@ def _initialize_writers(self, only_initialize_if_missing=False) -> None:
                     self.first_process = True
                     self.logger.info(f"Hook is writing from the hook with pid: {os.getpid()}\n")
                 else:
+                    if self.first_process is None:
+                        self.logger.warn(
+                            f"Unsupported Distributed Training Strategy Detected. \
+                            Sagemaker-Debugger will only write from one process. \
+                            The process with pid: {os.getpid()} will not be writing any data. \n"
+                        )
                     self.first_process = False
-                    self.logger.warn(
-                        f"Unsupported Distributed Training Strategy Detected.\n\
-                        Sagemaker-Debugger will only write from one process.\n\
-                        The process with pid: {os.getpid()} will not be writing any data. \n"
-                    )
                     return
 
         if self.save_all_workers is False:
@@ -546,6 +547,13 @@ def set_mode(self, mode):
 
     def export_collections(self):
         num_workers = self._get_num_workers()
+        if num_workers == 1 and self.first_process is False:
+            self.logger.warn(
+                f"Unsupported Distributed Training Strategy Detected. \
+                Sagemaker-Debugger will only write from one process. \
+                The process with pid: {os.getpid()} will not be writing any data. \n"
+            )
+            return
         if self.save_all_workers is False:
             if self.chief_worker != self.worker:
                 return