Files
lerobot/lerobot/scripts/server/policy_server.py
2025-06-03 18:03:42 +02:00

430 lines
17 KiB
Python

import itertools
import pickle # nosec
import time
from concurrent import futures
from queue import Queue
from typing import Generator, List, Optional
import async_inference_pb2 # type: ignore
import async_inference_pb2_grpc # type: ignore
import grpc
import torch
from datasets import load_dataset
from lerobot.common.policies.factory import get_policy_class
from lerobot.scripts.server.constants import environment_dt, idle_wait, inference_latency, supported_policies
from lerobot.scripts.server.helpers import (
TimedAction,
TimedObservation,
TinyPolicyConfig,
observations_similar,
setup_logging,
)
class PolicyServer(async_inference_pb2_grpc.AsyncInferenceServicer):
prefix = "policy_server"
info_bracket = "SERVER"
logger = setup_logging(prefix, info_bracket)
def __init__(self):
# Initialize dataset action generator (to debug this first version, will be removed in the future)
self.action_generator = itertools.cycle(self._stream_action_chunks_from_dataset())
self._setup_server()
self.actions_per_chunk = 20
self.actions_overlap = 10
self.running = True
def _setup_server(self) -> None:
"""Flushes server state when new client connects."""
# only running inference on the latest observation received by the server
self.observation_queue = Queue(maxsize=1)
self._predicted_timesteps = set()
self._predicted_observations = Queue(maxsize=1)
def Ready(self, request, context): # noqa: N802
client_id = context.peer()
self.logger.info(f"Client {client_id} connected and ready")
self._setup_server()
return async_inference_pb2.Empty()
def SendPolicyInstructions(self, request, context): # noqa: N802
"""Receive policy instructions from the robot client"""
client_id = context.peer()
self.logger.debug(f"Receiving policy instructions from {client_id}")
policy_specs = pickle.loads(request.data) # nosec
assert isinstance(policy_specs, TinyPolicyConfig), (
f"Policy specs must be a TinyPolicyConfig. Got {type(policy_specs)}"
)
self.logger.info(
f"Policy type: {policy_specs.policy_type} | "
f"Pretrained name or path: {policy_specs.pretrained_name_or_path} | "
f"Device: {policy_specs.device}"
)
assert policy_specs.policy_type in supported_policies, (
f"Policy type {policy_specs.policy_type} not supported. Supported policies: {supported_policies}"
)
self.device = policy_specs.device
self.policy_type = policy_specs.policy_type # act, pi0, etc.
policy_class = get_policy_class(self.policy_type)
start = time.time()
self.policy = policy_class.from_pretrained(policy_specs.pretrained_name_or_path)
self.policy.to(self.device)
end = time.time()
self.logger.info(f"Time taken to put policy on {self.device}: {end - start:.4f} seconds")
return async_inference_pb2.Empty()
def SendObservations(self, request_iterator, context): # noqa: N802
"""Receive observations from the robot client"""
client_id = context.peer()
self.logger.debug(f"Receiving observations from {client_id}")
for observation in request_iterator:
receive_time = time.time()
timed_observation = pickle.loads(observation.data) # nosec
deserialize_time = time.time()
self.logger.debug(f"Received observation #{timed_observation.get_timestep()}")
if not self._maybe_enqueue_observation(timed_observation):
continue
queue_time = time.time()
obs_timestep = timed_observation.get_timestep()
obs_timestamp = timed_observation.get_timestamp()
self.logger.info(
f"Received observation #{obs_timestep} | "
f"Client timestamp: {obs_timestamp:.6f} | "
f"Server timestamp: {receive_time:.6f} | "
)
if not hasattr(self, "previous_obs_timestamp"):
self.previous_obs_timestamp = obs_timestamp
self.logger.debug(
f"1/DeltaObsT (~frequency): {1 / (1e-6 + obs_timestamp - self.previous_obs_timestamp):.6f} Hz| "
f"Network latency: {receive_time - obs_timestamp:.6f}s | "
f"Deserialization time: {deserialize_time - receive_time:.6f}s | "
f"Queue time: {queue_time - deserialize_time:.6f}s | "
)
self.previous_obs_timestamp = obs_timestamp
return async_inference_pb2.Empty()
def StreamActions(self, request, context): # noqa: N802
"""Stream actions to the robot client"""
client_id = context.peer()
self.logger.debug(f"Client {client_id} connected for action streaming")
# Generate action based on the most recent observation and its timestep
try:
obs = self.observation_queue.get()
self.logger.info(
f"Running inference for observation #{obs.get_timestep()} (must_go: {obs.must_go})"
)
if obs:
self.last_predicted_obs = obs
self._predicted_timesteps.add(obs.get_timestep())
start_time = time.time()
action_chunk = self._predict_action_chunk(obs)
# action_chunk = self._read_action_chunk(obs)
inference_time = time.time() - start_time
start_time = time.time()
action_bytes = pickle.dumps(action_chunk) # nosec
serialize_time = time.time() - start_time
# Create and return the Action
action = async_inference_pb2.Action(transfer_state=obs.transfer_state, data=action_bytes)
self.logger.info(
f"Action chunk #{obs.get_timestep()} generated | Inference time: {inference_time:.6f}s |"
)
self.logger.debug(
f"Action chunk #{obs.get_timestep()} generated | "
f"Inference time: {inference_time:.6f}s |"
f"Serialize time: {serialize_time:.6f}s |"
f"Total time: {inference_time + serialize_time:.6f}s"
)
yield action
else:
self.logger.warning("No observation in queue yet!")
time.sleep(idle_wait)
except Exception as e:
self.logger.error(f"Error in StreamActions: {e}")
return async_inference_pb2.Empty()
def _enqueue_and_go(self, obs: TimedObservation):
# If queue is full, get the old observation to make room
if self.observation_queue.full():
# pops from queue
_ = self.observation_queue.get_nowait()
self.logger.debug("Observation queue was full, removed oldest observation")
# Now put the new observation (never blocks as queue is non-full here)
self.observation_queue.put(obs)
return True
def _obs_sanity_checks(self, obs: TimedObservation, previous_obs: TimedObservation) -> bool:
if obs.get_timestep() in self._predicted_timesteps:
self.logger.debug(f"Skipping observation #{obs.get_timestep()} - Timestep predicted already!")
return False
elif observations_similar(obs, previous_obs, atol=1):
self.logger.debug(
f"Skipping observation #{obs.get_timestep()} - Observation too similar to last obs predicted!"
)
return False
else:
return True
def _maybe_enqueue_observation(self, obs: TimedObservation) -> bool:
"""Enqueue an observation if it must go through processing, otherwise skip it.
Observations not in queue are never run through the policy network"""
if obs.must_go or not hasattr(self, "last_predicted_obs"):
self.logger.info(f"[MUST GO] Enqueued observation #{obs.get_timestep()} for direct processing!")
return self._enqueue_and_go(obs)
else:
if self._obs_sanity_checks(obs, self.last_predicted_obs):
return self._enqueue_and_go(obs)
else:
return False
def _time_action_chunk(self, t_0: float, action_chunk: list[torch.Tensor], i_0: int) -> list[TimedAction]:
"""Turn a chunk of actions into a list of TimedAction instances,
with the first action corresponding to t_0 and the rest corresponding to
t_0 + i*environment_dt for i in range(len(action_chunk))
"""
return [
TimedAction(t_0 + i * environment_dt, action, i_0 + i) for i, action in enumerate(action_chunk)
]
@torch.no_grad()
def _run_act_policy(self, observation: dict[str, torch.Tensor]) -> torch.Tensor:
"""Run ACT-like policies"""
start_time = time.time()
# prepare observation for policy forward pass
batch = self.policy.normalize_inputs(observation)
normalize_time = time.time()
self.logger.debug(f"Observation normalization time: {normalize_time - start_time:.6f}s")
if self.policy.config.image_features:
batch = dict(batch) # shallow copy so that adding a key doesn't modify the original
batch["observation.images"] = [batch[key] for key in self.policy.config.image_features]
prep_time = time.time()
self.logger.debug(f"Observation image preparation time: {prep_time - normalize_time:.6f}s")
# forward pass outputs up to policy.config.n_action_steps != actions_per_chunk
actions = self.policy.model(batch)[0][:, : self.actions_per_chunk]
actions = self.policy.unnormalize_outputs({"action": actions})["action"]
end_time = time.time()
self.logger.info(f"[ACT] Action chunk generation total time: {end_time - start_time:.6f}s")
return actions
@torch.no_grad()
def _run_pi0_policy(self, observation: dict[str, torch.Tensor]) -> torch.Tensor:
"""Run PI0-like policies"""
raise NotImplementedError("PI0 policy not implemented yet")
@torch.no_grad()
def _run_smolvla_policy(
self, observation: dict[str, torch.Tensor], noise: Optional[torch.Tensor] = None
) -> torch.Tensor:
"""Run smolvla-like policies"""
observation = self.policy.normalize_inputs(observation)
images, img_masks = self.policy.prepare_images(observation)
state = self.policy.prepare_state(observation)
lang_tokens, lang_masks = self.policy.prepare_language(observation)
actions = self.policy.model.sample_actions(
images, img_masks, lang_tokens, lang_masks, state, noise=noise
)
# Unpad actions
original_action_dim = self.policy.config.action_feature.shape[0]
actions = actions[:, :, :original_action_dim]
actions = self.policy.unnormalize_outputs(
{"action": actions, "robot_type": [self.policy.config.robot_type]}
)["action"]
return actions
def _get_action_chunk(
self, observation: dict[str, torch.Tensor], policy_type: str = "act"
) -> torch.Tensor:
"""Get an action chunk from the policy"""
if policy_type == "act":
return self._run_act_policy(observation)
elif policy_type == "smolvla":
return self._run_smolvla_policy(observation)
else:
raise ValueError(f"Policy class {policy_type} not supported")
def _predict_action_chunk(self, observation_t: TimedObservation) -> list[TimedAction]:
"""Predict an action based on the observation"""
"""1. Prepare observation"""
start_time = time.time()
observation = {
"robot_type": [self.policy.config.robot_type],
}
for k, v in observation_t.get_observation().items():
if isinstance(v, torch.Tensor): # VLAs present natural-language instructions
if "image" in k:
# Add batch dimension first, then reorder to NCHW format, then normalize to [0, 1]
observation[k] = (
v.unsqueeze(0).permute(0, 3, 1, 2).to(self.device, non_blocking=True) / 255.0
)
else:
observation[k] = v.unsqueeze(0).to(self.device, non_blocking=True)
else:
observation[k] = v # textual instructions are passed as a list of strings
prep_time = time.time()
self.logger.debug(f"Observation preparation time: {prep_time - start_time:.6f}s")
"""2. Get action chunk"""
action_tensor = self._get_action_chunk(observation, self.policy_type)
action_tensor = action_tensor.squeeze(0)
# Move to CPU before serializing
action_tensor = action_tensor.cpu()
post_inference_time = time.time()
self.logger.debug(f"Post-inference processing start: {post_inference_time - prep_time:.6f}s")
if action_tensor.dim() == 1:
# No chunk dimension, so repeat action to create a (dummy) chunk of actions
action_tensor = action_tensor.repeat(self.actions_per_chunk, 1)
action_chunk = self._time_action_chunk(
observation_t.get_timestamp(), list(action_tensor), observation_t.get_timestep()
)
chunk_time = time.time()
self.logger.debug(f"Action chunk creation time: {chunk_time - post_inference_time:.6f}s")
time.sleep(
max(0, inference_latency - max(0, chunk_time - start_time))
) # sleep to control inference latency
return action_chunk
def _stream_action_chunks_from_dataset(self) -> Generator[List[torch.Tensor], None, None]:
"""Stream chunks of actions from a prerecorded dataset.
Returns:
Generator that yields chunks of actions from the dataset
"""
import warnings
warnings.warn(
"This method is deprecated and will be removed in the future.", DeprecationWarning, stacklevel=2
)
dataset = load_dataset("fracapuano/so100_test", split="train").with_format("torch")
# 1. Select the action column only, where you will find tensors with 6 elements
actions = dataset["action"]
action_indices = torch.arange(len(actions))
# 2. Chunk the iterable of tensors into chunks with 10 elements each
# sending only first element for debugging
indices_chunks = action_indices.unfold(
0, self.actions_per_chunk, self.actions_per_chunk - self.actions_overlap
)
for idx_chunk in indices_chunks:
yield actions[idx_chunk[0] : idx_chunk[-1] + 1, :]
def _read_action_chunk(self, observation: Optional[TimedObservation] = None) -> list[TimedAction]:
"""Dummy function for predicting action chunk given observation.
Instead of computing actions on-the-fly, this method streams
actions from a prerecorded dataset.
"""
import warnings
warnings.warn(
"This method is deprecated and will be removed in the future.", DeprecationWarning, stacklevel=2
)
start_time = time.time()
if not observation:
observation = TimedObservation(timestamp=time.time(), observation={}, timestep=0)
# Get chunk of actions from the generator
actions_chunk = next(self.action_generator)
# Return a list of TimedActions, with timestamps starting from the observation timestamp
actions_chunk = self._time_action_chunk(
observation.get_timestamp(), actions_chunk, observation.get_timestep()
)
chunk_time = time.time()
self.logger.debug(f"Action chunk creation time: {chunk_time - start_time:.6f}s")
# slow action generation, emulates inference time
time.sleep(max(0, inference_latency - max(0, chunk_time - start_time)))
return actions_chunk
def stop(self):
"""Stop the server"""
self.running = False
self.logger.info("Server stopping...")
def serve():
port = 8080
# Create the server instance first
policy_server = PolicyServer()
# Setup and start gRPC server
server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))
async_inference_pb2_grpc.add_AsyncInferenceServicer_to_server(policy_server, server)
server.add_insecure_port(f"[::]:{port}")
server.start()
policy_server.logger.info(f"PolicyServer started on port {port}")
try:
# Use the running attribute to control server lifetime
while policy_server.running:
time.sleep(1) # Check every second instead of sleeping indefinitely
except KeyboardInterrupt:
policy_server.stop()
policy_server.logger.info("Keyboard interrupt received")
if __name__ == "__main__":
serve()