ray.rllib.callbacks.callbacks.RLlibCallback.on_episode_step#

RLlibCallback.on_episode_step(*, episode: SingleAgentEpisode | MultiAgentEpisode | EpisodeV2, env_runner: EnvRunner | None = None, metrics_logger: MetricsLogger | None = None, env: gymnasium.Env | None = None, env_index: int, rl_module: RLModule | None = None, worker: EnvRunner | None = None, base_env: BaseEnv | None = None, policies: Dict[str, Policy] | None = None, **kwargs) → None[source]#

Called on each episode step (after the action(s) has/have been logged).

Note that on the new API stack, this callback is also called after the final step of an episode, meaning when terminated/truncated are returned as True from the env.step() call, but is still provided with the non-finalized episode object (meaning the data has NOT been converted to numpy arrays yet).

The exact time of the call of this callback is after env.step([action]) and also after the results of this step (observation, reward, terminated, truncated, infos) have been logged to the given episode object.

Parameters:

  • episode – The just stepped SingleAgentEpisode or MultiAgentEpisode object (after env.step() and after returned obs, rewards, etc.. have been logged to the episode object).

  • env_runner – Reference to the EnvRunner running the env and episode.

  • metrics_logger – The MetricsLogger object inside the env_runner. Can be used to log custom metrics during env/episode stepping.

  • env – The gym.Env or gym.vector.Env object running the started episode.

  • env_index – The index of the sub-environment that has just been stepped.

  • rl_module – The RLModule used to compute actions for stepping the env. In a single-agent setup, this is a (single-agent) RLModule, in a multi- agent setup, this will be a MultiRLModule.

  • kwargs – Forward compatibility placeholder.