import logging from typing import Callable, Iterable, List, Optional, Type from ray.rllib.agents.trainer import Trainer, COMMON_CONFIG from ray.rllib.env.env_context import EnvContext from ray.rllib.evaluation.worker_set import WorkerSet from ray.rllib.execution.rollout_ops import ParallelRollouts, ConcatBatches from ray.rllib.execution.train_ops import TrainOneStep from ray.rllib.execution.metric_ops import StandardMetricsReporting from ray.rllib.policy import Policy from ray.rllib.utils import add_mixins from ray.rllib.utils.annotations import override, DeveloperAPI from ray.rllib.utils.typing import EnvConfigDict, EnvType, ResultDict, \ TrainerConfigDict logger = logging.getLogger(__name__) def default_execution_plan(workers: WorkerSet, config: TrainerConfigDict): # Collects experiences in parallel from multiple RolloutWorker actors. rollouts = ParallelRollouts(workers, mode="bulk_sync") # Combine experiences batches until we hit `train_batch_size` in size. # Then, train the policy on those experiences and update the workers. train_op = rollouts.combine( ConcatBatches( min_batch_size=config["train_batch_size"], count_steps_by=config["multiagent"]["count_steps_by"], )).for_each(TrainOneStep(workers)) # Add on the standard episode reward, etc. metrics reporting. This returns # a LocalIterator[metrics_dict] representing metrics for each train step. return StandardMetricsReporting(train_op, workers, config) @DeveloperAPI def build_trainer( name: str, *, default_config: Optional[TrainerConfigDict] = None, validate_config: Optional[Callable[[TrainerConfigDict], None]] = None, default_policy: Optional[Type[Policy]] = None, get_policy_class: Optional[Callable[[TrainerConfigDict], Optional[Type[ Policy]]]] = None, validate_env: Optional[Callable[[EnvType, EnvContext], None]] = None, before_init: Optional[Callable[[Trainer], None]] = None, after_init: Optional[Callable[[Trainer], None]] = None, before_evaluate_fn: Optional[Callable[[Trainer], None]] = None, mixins: Optional[List[type]] = None, execution_plan: Optional[Callable[[ WorkerSet, TrainerConfigDict ], Iterable[ResultDict]]] = default_execution_plan) -> Type[Trainer]: """Helper function for defining a custom trainer. Functions will be run in this order to initialize the trainer: 1. Config setup: validate_config, get_policy 2. Worker setup: before_init, execution_plan 3. Post setup: after_init Args: name (str): name of the trainer (e.g., "PPO") default_config (Optional[TrainerConfigDict]): The default config dict of the algorithm, otherwise uses the Trainer default config. validate_config (Optional[Callable[[TrainerConfigDict], None]]): Optional callable that takes the config to check for correctness. It may mutate the config as needed. default_policy (Optional[Type[Policy]]): The default Policy class to use. get_policy_class (Optional[Callable[ TrainerConfigDict, Optional[Type[Policy]]]]): Optional callable that takes a config and returns the policy class or None. If None is returned, will use `default_policy` (which must be provided then). validate_env (Optional[Callable[[EnvType, EnvContext], None]]): Optional callable to validate the generated environment (only on worker=0). before_init (Optional[Callable[[Trainer], None]]): Optional callable to run before anything is constructed inside Trainer (Workers with Policies, execution plan, etc..). Takes the Trainer instance as argument. after_init (Optional[Callable[[Trainer], None]]): Optional callable to run at the end of trainer init (after all Workers and the exec. plan have been constructed). Takes the Trainer instance as argument. before_evaluate_fn (Optional[Callable[[Trainer], None]]): Callback to run before evaluation. This takes the trainer instance as argument. mixins (list): list of any class mixins for the returned trainer class. These mixins will be applied in order and will have higher precedence than the Trainer class. execution_plan (Optional[Callable[[WorkerSet, TrainerConfigDict], Iterable[ResultDict]]]): Optional callable that sets up the distributed execution workflow. Returns: Type[Trainer]: A Trainer sub-class configured by the specified args. """ original_kwargs = locals().copy() base = add_mixins(Trainer, mixins) class trainer_cls(base): _name = name _default_config = default_config or COMMON_CONFIG _policy_class = default_policy def __init__(self, config=None, env=None, logger_creator=None): Trainer.__init__(self, config, env, logger_creator) def _init(self, config: TrainerConfigDict, env_creator: Callable[[EnvConfigDict], EnvType]): # Validate config via custom validation function. if validate_config: validate_config(config) # No `get_policy_class` function. if get_policy_class is None: # Default_policy must be provided (unless in multi-agent mode, # where each policy can have its own default policy class. if not config["multiagent"]["policies"]: assert default_policy is not None self._policy_class = default_policy # Query the function for a class to use. else: self._policy_class = get_policy_class(config) # If None returned, use default policy (must be provided). if self._policy_class is None: assert default_policy is not None self._policy_class = default_policy if before_init: before_init(self) # Creating all workers (excluding evaluation workers). self.workers = self._make_workers( env_creator=env_creator, validate_env=validate_env, policy_class=self._policy_class, config=config, num_workers=self.config["num_workers"]) self.execution_plan = execution_plan self.train_exec_impl = execution_plan(self.workers, config) if after_init: after_init(self) @override(Trainer) def step(self): res = next(self.train_exec_impl) return res @override(Trainer) def _before_evaluate(self): if before_evaluate_fn: before_evaluate_fn(self) @override(Trainer) def __getstate__(self): state = Trainer.__getstate__(self) state["train_exec_impl"] = ( self.train_exec_impl.shared_metrics.get().save()) return state @override(Trainer) def __setstate__(self, state): Trainer.__setstate__(self, state) self.train_exec_impl.shared_metrics.get().restore( state["train_exec_impl"]) @staticmethod @override(Trainer) def with_updates(**overrides) -> Type[Trainer]: """Build a copy of this trainer class with the specified overrides. Keyword Args: overrides (dict): use this to override any of the arguments originally passed to build_trainer() for this policy. Returns: Type[Trainer]: A the Trainer sub-class using `original_kwargs` and `overrides`. Examples: >>> MyClass = SomeOtherClass.with_updates({"name": "Mine"}) >>> issubclass(MyClass, SomeOtherClass) ... False >>> issubclass(MyClass, Trainer) ... True """ return build_trainer(**dict(original_kwargs, **overrides)) trainer_cls.__name__ = name trainer_cls.__qualname__ = name return trainer_cls