set file_writer as field

examples/shields/rl/callbacks.py

@@ -28,14 +28,13 @@ class ShieldInfoCallback(DefaultCallbacks):
 
 class MyCallbacks(DefaultCallbacks):
     def on_algorithm_init(self, algorithm: Algorithm, **kwargs):
-        file_writer = tf.summary.create_file_writer(algorithm.logdir)
-        with file_writer.as_default():
+        self.file_writer = tf.summary.create_file_writer(algorithm.logdir)
+        with self.file_writer.as_default():
             tf.summary.text("first_text", "testing", step=0)
 
     def on_episode_start(self, *, worker: RolloutWorker, base_env: BaseEnv, policies: Dict[PolicyID, Policy], episode, env_index, **kwargs) -> None:
-        file_writer = tf.summary.create_file_writer(algorithm.logdir)
-        with file_writer.as_default():
-            tf.summary.text("first_text", "testing", step=0)
+        with self.file_writer.as_default():
+            tf.summary.text("first_text_from_episode_start", "testing_in_episode", step=0)
         # print(F"Epsiode started Environment: {base_env.get_sub_environments()}")
         env = base_env.get_sub_environments()[0]
         episode.user_data["count"] = 0