petals-api / src /client /remote_block.py
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# Note: this code is being actively modified by justheuristic. If you want to change anything about it, please warn me.
from __future__ import annotations
import asyncio
import random
from typing import Any, AsyncIterator, Dict, Optional
import torch
from hivemind.compression import deserialize_torch_tensor, serialize_torch_tensor
from hivemind.moe.client.expert import RemoteExpert, RemoteExpertWorker
from hivemind.moe.expert_uid import ExpertInfo
from hivemind.p2p import P2P, StubBase
from hivemind.proto import runtime_pb2
from hivemind.utils import anext, get_logger, nested_flatten, use_hivemind_log_handler
from src.data_structures import RemoteModuleInfo
from src.dht_utils import ModuleUID
from src.server.handler import TransformerConnectionHandler
use_hivemind_log_handler("in_root_logger")
logger = get_logger(__file__)
class RemoteTransformerBlock(RemoteExpert):
"""A class that interacts with a remote module on a specific server for forward/backward or inference"""
def __init__(self, peers_info: RemoteModuleInfo, p2p: P2P):
peer_info = ExpertInfo(peers_info.uid, random.choice(list(peers_info.peer_ids))) # TODO replace this
super().__init__(peer_info, p2p)
@property
def stub(self) -> StubBase:
return TransformerConnectionHandler.get_stub(self.p2p, self.peer_id)
def forward(self, inputs: torch.Tensor, **kwargs):
for k, v in kwargs.items():
assert v is None or v is False, f"Extra keyword arguments are not yet supported (got {k} = {v})"
return super().forward(inputs)
def inference_session(self) -> RemoteTransformerBlockInferenceSession:
"""Initialize a new inference session with the specified remote server"""
_ = self.info # create _info manually since the built-in property will not work inside RemoteExpertWorker
return RemoteExpertWorker.run_coroutine(RemoteTransformerBlockInferenceSession._create(self))
def begin_inference_session(self):
logger.warning("beging_inference_session was renamed to just inference_session")
return self.inference_session()
class RemoteTransformerBlockInferenceSession:
"""An interface to a single multi-step *inference* session for a specific remote module with a specific server"""
def __init__(self, uid: ModuleUID, info: Dict[str, Any], inputs_queue: asyncio.Queue, outputs_aiter: AsyncIterator):
self.uid, self.info = uid, info
# warning: this code manages async objects that are only usable inside RemoteExpertWorker's background thread;
# using them in any other EventLoop may cause side-effects including, headaches, diarrhea, and loss of sleep
self._inputs_queue: asyncio.Queue[runtime_pb2.ExpertRequest] = inputs_queue
self._outputs_stream: AsyncIterator[runtime_pb2.ExpertResponse] = outputs_aiter
self.stepped = False
self.closed = False
@classmethod
async def _create(
cls, remote_module: RemoteTransformerBlock, timeout: Optional[float] = None
) -> RemoteTransformerBlockInferenceSession:
"""Create a new session for a given remote module. This code is meant to be run inside RemoteExpertWorker"""
inputs_queue = asyncio.Queue()
outputs_stream = await remote_module.stub.rpc_inference(
cls._read_inputs_from_queue(inputs_queue, timeout), timeout=timeout
)
return cls(remote_module.uid, remote_module.info, inputs_queue, outputs_stream)
@staticmethod
async def _read_inputs_from_queue(queue: asyncio.Queue, timeout: Optional[float]) -> AsyncIterator:
while True:
next_input_message = await asyncio.wait_for(queue.get(), timeout)
yield next_input_message
if not next_input_message.uid and not next_input_message.tensors:
break # this message means "done sending"
def step(self, new_hidden_states: torch.Tensor):
"""Inference step: send a chunk of input tensors and receive a chunk of outputs"""
if self.closed:
raise Exception("Session is closed, cannot perform step")
# serialize inputs and put them into the queue
inputs = (new_hidden_states,)
outputs_serialized = RemoteExpertWorker.run_coroutine(
self._step(
runtime_pb2.ExpertRequest(
uid=self.uid,
tensors=[
serialize_torch_tensor(tensor, proto.compression)
for tensor, proto in zip(inputs, nested_flatten(self.info["forward_schema"]))
],
)
)
)
outputs = list(map(deserialize_torch_tensor, outputs_serialized.tensors))
assert outputs[0].shape == inputs[0].shape, f"expected outputs[0] to be hidden states but got {outputs[0]}"
return outputs[0]
async def _step(self, inputs_serialized: runtime_pb2.ExpertRequest) -> runtime_pb2.ExpertResponse:
"""Inference step on serialized data. This code is meant to be run inside RemoteExpertWorker"""
await self._inputs_queue.put(inputs_serialized)
self.stepped = True
return await anext(self._outputs_stream)
def close(self):
"""Finish a given inference session, close the underlying connection"""
if self._outputs_stream is None:
return # already closed
RemoteExpertWorker.run_coroutine(self._aclose_stream())
self._outputs_stream = self._inputs_queue = None
self.closed = True
async def _aclose_stream(self):
"""Close the inference session. This code is meant to be run inside RemoteExpertWorker"""
if self._outputs_stream is None:
return # already closed
if self.stepped:
await self._inputs_queue.put(runtime_pb2.ExpertRequest()) # empty request will trigger end of session
try:
await anext(self._outputs_stream)
except StopAsyncIteration:
pass
def __del__(self):
self.close()
def __enter__(self):
assert not self.closed
return self
def __exit__(self, *exc_details):
self.close()