[rllib] Support Nested Configuration Merging (#1268)

python/ray/rllib/agent.py

@@ -25,6 +25,37 @@ logger = logging.getLogger(__name__)
 logger.setLevel(logging.INFO)
 
 
+def _deep_update(original, new_dict, new_keys_allowed, whitelist):
+    """Updates original dict with values from new_dict recursively.
+    If new key is introduced in new_dict, then if new_keys_allowed is not
+    True, an error will be thrown. Further, for sub-dicts, if the key is
+    in the whitelist, then new subkeys can be introduced.
+
+    Args:
+        original (dict): Dictionary with default values.
+        new_dict (dict): Dictionary with values to be updated
+        new_keys_allowed (bool): Whether new keys are allowed.
+        whitelist (list): List of keys that correspond to dict values
+            where new subkeys can be introduced. This is only at
+            the top level.
+    """
+    for k, value in new_dict.items():
+        if k not in original and k != "env":
+            if not new_keys_allowed:
+                raise Exception(
+                    "Unknown config parameter `{}` ".format(k))
+            else:
+                logger.warn("`{}` not in default configuration...".format(k))
+        if type(original.get(k)) is dict:
+            if k in whitelist:
+                _deep_update(original[k], value, True, [])
+            else:
+                _deep_update(original[k], value, new_keys_allowed, [])
+        else:
+            original[k] = value
+    return original
+
+
 class Agent(Trainable):
     """All RLlib agents extend this base class.
 
@@ -40,6 +71,7 @@ class Agent(Trainable):
     """
 
     _allow_unknown_configs = False
+    _allow_unknown_subkeys = []
     _default_logdir = "/tmp/ray"
 
     def __init__(
@@ -67,13 +99,10 @@ class Agent(Trainable):
             self.env_creator = lambda: gym.make(env)
         self.config = self._default_config.copy()
         self.registry = registry
-        if not self._allow_unknown_configs:
-            for k in config.keys():
-                if k not in self.config and k != "env":
-                    raise Exception(
-                        "Unknown agent config `{}`, "
-                        "all agent configs: {}".format(k, self.config.keys()))
-        self.config.update(config)
+
+        self.config = _deep_update(self.config, config,
+                                   self._allow_unknown_configs,
+                                   self._allow_unknown_subkeys)
 
         if logger_creator:
             self._result_logger = logger_creator(self.config)

python/ray/rllib/dqn/dqn.py

@@ -111,6 +111,7 @@ DEFAULT_CONFIG = dict(
 
 class DQNAgent(Agent):
     _agent_name = "DQN"
+    _allow_unknown_subkeys = ["model", "optimizer", "tf_session_args"]
     _default_config = DEFAULT_CONFIG
 
     def _init(self):

python/ray/rllib/ppo/ppo.py

@@ -83,6 +83,7 @@ DEFAULT_CONFIG = {
 
 class PPOAgent(Agent):
     _agent_name = "PPO"
+    _allow_unknown_subkeys = ["model", "tf_session_args"]
     _default_config = DEFAULT_CONFIG
 
     def _init(self):

python/ray/rllib/tuned_examples/pong-a3c-pytorch.yaml

@@ -0,0 +1,17 @@
+pong-a3c-pytorch-cnn:
+    env: PongDeterministic-v4
+    run: A3C
+    resources:
+        cpu: 16
+        driver_cpu_limit: 1
+    config:
+        num_workers: 16
+        num_batches_per_iteration: 1000
+        batch_size: 20
+        use_lstm: false
+        use_pytorch: true
+        model:
+            grayscale: true
+            zero_mean: false
+            dim: 80
+            channel_major: true