[RLlib] Add timeout to filter synchronization. (#25959)

rllib/algorithms/algorithm.py

@@ -612,7 +612,12 @@ class Algorithm(Trainable):
 
         if hasattr(self, "workers") and isinstance(self.workers, WorkerSet):
             # Sync filters on workers.
-            self._sync_filters_if_needed(self.workers)
+            self._sync_filters_if_needed(
+                self.workers,
+                timeout_seconds=self.config[
+                    "sync_filters_on_rollout_workers_timeout_s"
+                ],
+            )
 
             # Collect worker metrics and add combine them with `results`.
             if self.config["_disable_execution_plan_api"]:
@@ -674,7 +679,12 @@ class Algorithm(Trainable):
             self.evaluation_workers.sync_weights(
                 from_worker=self.workers.local_worker()
             )
-            self._sync_filters_if_needed(self.evaluation_workers)
+            self._sync_filters_if_needed(
+                self.evaluation_workers,
+                timeout_seconds=self.config[
+                    "sync_filters_on_rollout_workers_timeout_s"
+                ],
+            )
 
         if self.config["custom_eval_function"]:
             logger.info(
@@ -1597,12 +1607,15 @@ class Algorithm(Trainable):
                 '(e.g., YourEnvCls) or a registered env id (e.g., "your_env").'
             )
 
-    def _sync_filters_if_needed(self, workers: WorkerSet):
+    def _sync_filters_if_needed(
+        self, workers: WorkerSet, timeout_seconds: Optional[float] = None
+    ):
         if self.config.get("observation_filter", "NoFilter") != "NoFilter":
             FilterManager.synchronize(
                 workers.local_worker().filters,
                 workers.remote_workers(),
                 update_remote=self.config["synchronize_filters"],
+                timeout_seconds=timeout_seconds,
             )
             logger.debug(
                 "synchronized filters: {}".format(workers.local_worker().filters)
@@ -2273,6 +2286,7 @@ class Algorithm(Trainable):
                         ignore=self.config["ignore_worker_failures"],
                         recreate=self.config["recreate_failed_workers"],
                     )
+
         return results, train_iter_ctx
 
     def _run_one_evaluation(

rllib/algorithms/algorithm_config.py

@@ -189,6 +189,7 @@ class AlgorithmConfig:
         # TODO: Set this flag still in the config or - much better - in the
         #  RolloutWorker as a property.
         self.in_evaluation = False
+        self.sync_filters_on_rollout_workers_timeout_s = 60.0
 
         # `self.reporting()`
         self.keep_per_episode_custom_metrics = False

rllib/evaluation/tests/test_trajectory_view_api.py

@@ -64,9 +64,6 @@ class TestTrajectoryViewAPI(unittest.TestCase):
             policy = algo.get_policy()
             view_req_model = policy.model.view_requirements
             view_req_policy = policy.view_requirements
-            print(_)
-            print(view_req_policy)
-            print(view_req_model)
             assert len(view_req_model) == 1, view_req_model
             assert len(view_req_policy) == 11, view_req_policy
             for key in [
@@ -321,8 +318,7 @@ class TestTrajectoryViewAPI(unittest.TestCase):
             normalize_actions=False,
             num_envs=1,
         )
-        batch = rollout_worker_w_api.sample()
-        print(batch)
+        batch = rollout_worker_w_api.sample()  # noqa: F841
 
     def test_counting_by_agent_steps(self):
         config = copy.deepcopy(ppo.DEFAULT_CONFIG)

rllib/utils/filter_manager.py

@@ -1,5 +1,11 @@
+import logging
+from typing import Optional
+
 import ray
 from ray.rllib.utils.annotations import DeveloperAPI
+from ray.exceptions import GetTimeoutError
+
+logger = logging.getLogger(__name__)
 
 
 @DeveloperAPI
@@ -10,7 +16,12 @@ class FilterManager:
 
     @staticmethod
     @DeveloperAPI
-    def synchronize(local_filters, remotes, update_remote=True):
+    def synchronize(
+        local_filters,
+        remotes,
+        update_remote=True,
+        timeout_seconds: Optional[float] = None,
+    ):
         """Aggregates all filters from remote evaluators.
 
         Local copy is updated and then broadcasted to all remote evaluators.
@@ -19,14 +30,37 @@ class FilterManager:
             local_filters: Filters to be synchronized.
             remotes: Remote evaluators with filters.
             update_remote: Whether to push updates to remote filters.
+            timeout_seconds: How long to wait for filter to get or set filters
         """
-        remote_filters = ray.get(
-            [r.get_filters.remote(flush_after=True) for r in remotes]
-        )
+        try:
+            remote_filters = ray.get(
+                [r.get_filters.remote(flush_after=True) for r in remotes],
+                timeout=timeout_seconds,
+            )
+        except GetTimeoutError:
+            logger.error(
+                "Failed to get remote filters from a rollout worker in "
+                "FilterManager. "
+                "Filtered "
+                "metrics may be computed, but filtered wrong."
+            )
+
         for rf in remote_filters:
             for k in local_filters:
                 local_filters[k].apply_changes(rf[k], with_buffer=False)
         if update_remote:
             copies = {k: v.as_serializable() for k, v in local_filters.items()}
             remote_copy = ray.put(copies)
-            [r.sync_filters.remote(remote_copy) for r in remotes]
+
+            try:
+                ray.get(
+                    [r.sync_filters.remote(remote_copy) for r in remotes],
+                    timeout=timeout_seconds,
+                )
+            except GetTimeoutError:
+                logger.error(
+                    "Failed to set remote filters to a rollout worker in "
+                    "FilterManager. "
+                    "Filtered "
+                    "metrics may be computed, but filtered wrong."
+                )