Refactor LocalLogger to remove the dependency on LogSender. (#139)

* Refactor LocalLogger to remove the dependency on LogSender.

* call the LocalLogger.initialize() before EventType.ABOUT_TO_START_RUN.

Author: yhwen

nvflare/apis/utils/local_logger.py

@@ -15,25 +15,44 @@
 import logging
 import threading
 
-from nvflare.app_common.widgets.streaming import LogSender
-
 
 class LocalLogger:
+    handlers = None
     loggers = {}
     lock = threading.Lock()
 
+    @staticmethod
+    def initialize():
+        """        Initialize the LocalLogger to keep all the handlers before the adding of LogSender handler.
+        Returns:
+
+        """
+        if not LocalLogger.handlers:
+            LocalLogger.handlers = []
+            for handler in logging.root.handlers:
+                LocalLogger.handlers.append(handler)
+
     @staticmethod
     def get_logger(name=None) -> logging.Logger:
+        """        Get a logger only do the local logging.
+        Args:
+            name: logger name
+
+        Returns: local_logger
+
+        """
         with LocalLogger.lock:
+            if not LocalLogger.handlers:
+                LocalLogger.initialize()
+
             logger = LocalLogger.loggers.get(name)
             if logger:
                 return logger
 
             logger = logging.getLogger(name)
             LocalLogger.loggers[name] = logger
-            for handler in logging.root.handlers:
-                if not isinstance(handler, LogSender):
-                    logger.addHandler(handler)
+            for handler in LocalLogger.handlers:
+                logger.addHandler(handler)
             logger.propagate = False
 
             return logger

nvflare/private/fed/client/client_runner.py

@@ -22,6 +22,7 @@
 from nvflare.apis.fl_context import FLContext
 from nvflare.apis.shareable import Shareable, make_reply
 from nvflare.apis.signal import Signal
+from nvflare.apis.utils.local_logger import LocalLogger
 from nvflare.private.defs import SpecialTaskName
 from nvflare.private.defs import TaskConstant
 from nvflare.widgets.info_collector import GroupInfoCollector, InfoCollector
@@ -269,6 +270,9 @@ def _try_run(self):
 
     def run(self, app_root, args):
         with self.engine.new_context() as fl_ctx:
+            # initialize the LocalLogger to keep all the local handlers.
+            LocalLogger.initialize()
+
             self.fire_event(EventType.ABOUT_TO_START_RUN, fl_ctx)
             fl_ctx.set_prop(FLContextKey.APP_ROOT, app_root, sticky=True)
             fl_ctx.set_prop(FLContextKey.ARGS, args, sticky=True)