#!/usr/bin/env python3 # Copyright 2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions # are met: # * Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # * Redistributions in binary form must reproduce the above copyright # notice, this list of conditions and the following disclaimer in the # documentation and/or other materials provided with the distribution. # * Neither the name of NVIDIA CORPORATION nor the names of its # contributors may be used to endorse or promote products derived # from this software without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY # EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR # CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, # PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR # PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY # OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. import queue import threading import grpc from tritonclient.utils import * from ._infer_result import InferResult from ._utils import get_cancelled_error, get_error_grpc, raise_error class _InferStream: """Supports sending inference requests and receiving corresponding requests on a gRPC bi-directional stream. Parameters ---------- callback : function Python function that is invoked upon receiving response from the underlying stream. The function must reserve the last two arguments (result, error) to hold :py:class:`InferResult` and :py:class:`InferenceServerException` objects respectively which will be provided to the function when executing the callback. The ownership of these objects will be given to the user. The 'error' would be None for a successful inference. verbose : bool Enables verbose mode if set True. """ def __init__(self, callback, verbose): self._callback = callback self._verbose = verbose self._request_queue = queue.Queue() self._handler = None self._cancelled = False self._active = True self._response_iterator = None def __del__(self): self.close(cancel_requests=True) def close(self, cancel_requests=False): """Gracefully close underlying gRPC streams. If cancel_requests is set True, then client cancels all the pending requests and closes the stream. If set False, the call blocks till all the pending requests on the stream are processed. """ if cancel_requests and self._response_iterator: self._response_iterator.cancel() self._cancelled = True if self._handler is not None: if not self._cancelled: self._request_queue.put(None) if self._handler.is_alive(): self._handler.join() if self._verbose: print("stream stopped...") self._handler = None def _init_handler(self, response_iterator): """Initializes the handler to process the response from stream and execute the callbacks. Parameters ---------- response_iterator : iterator The iterator over the gRPC response stream. """ self._response_iterator = response_iterator if self._handler is not None: raise_error("Attempted to initialize already initialized InferStream") # Create a new thread to handle the gRPC response stream self._handler = threading.Thread(target=self._process_response) self._handler.start() if self._verbose: print("stream started...") def _enqueue_request(self, request): """Enqueues the specified request object to be provided in gRPC request stream. Parameters ---------- request : ModelInferRequest The protobuf message holding the ModelInferRequest """ if self._active: self._request_queue.put(request) else: raise_error( "The stream is no longer in valid state, the error detail " "is reported through provided callback. A new stream should " "be started after stopping the current stream." ) def _get_request(self): """Returns the request details in the order they were added. The call to this function will block until the requests are available in the queue. InferStream._enqueue_request adds the request to the queue. Returns ------- protobuf message The ModelInferRequest protobuf message. """ request = self._request_queue.get() return request def _process_response(self): """Worker thread function to iterate through the response stream and executes the provided callbacks. """ try: for response in self._response_iterator: if self._verbose: print(response) result = error = None if response.error_message != "": error = InferenceServerException(msg=response.error_message) else: result = InferResult(response.infer_response) self._callback(result=result, error=error) except grpc.RpcError as rpc_error: # On GRPC error, refresh the active state to indicate if the stream # can still be used. The stream won't be closed here as the thread # executing this function is managed by stream and may cause # circular wait self._active = self._response_iterator.is_active() if rpc_error.code() == grpc.StatusCode.CANCELLED: error = get_cancelled_error(rpc_error.details()) else: error = get_error_grpc(rpc_error) self._callback(result=None, error=error) class _RequestIterator: """An iterator class to provide data to gRPC request stream. Parameters ---------- stream : InferStream The InferStream that holds the context to an active stream. """ def __init__(self, stream): self._stream = stream def __iter__(self): return self def __next__(self): request = self._stream._get_request() if request is None: raise StopIteration return request