| # Licensed to the Apache Software Foundation (ASF) under one |
| # or more contributor license agreements. See the NOTICE file |
| # distributed with this work for additional information |
| # regarding copyright ownership. The ASF licenses this file |
| # to you under the Apache License, Version 2.0 (the |
| # "License"); you may not use this file except in compliance |
| # with the License. You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, |
| # software distributed under the License is distributed on an |
| # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| # KIND, either express or implied. See the License for the |
| # specific language governing permissions and limitations |
| # under the License. |
| import asyncio |
| import queue |
| from concurrent.futures import Future |
| |
| from aiohttp.client_exceptions import ( |
| ClientConnectionError, |
| ClientPayloadError, |
| ServerDisconnectedError, |
| ) |
| |
| from gremlin_python.driver import resultset, useragent |
| from gremlin_python.driver.aiohttp.transport import AiohttpHTTPTransport |
| |
| __author__ = 'David M. Brown (davebshow@gmail.com)' |
| |
| _TRANSPORT_ERRORS = (ClientConnectionError, ClientPayloadError, ServerDisconnectedError, asyncio.IncompleteReadError) |
| |
| _CONNECTION_ERROR_MSG = ( |
| "Connection to server closed unexpectedly. " |
| "Ensure that the server is still reachable and the connection has not been closed by the server or a network device." |
| ) |
| |
| |
| class GremlinServerError(Exception): |
| def __init__(self, status): |
| super(GremlinServerError, self).__init__('{0}: {1}'.format(status['code'], status['message'])) |
| self.status_code = status['code'] |
| self.status_message = status['message'] |
| self.status_exception = status['exception'] |
| |
| |
| class GremlinConnectionError(Exception): |
| """Raised when a transport-level failure occurs communicating with the server.""" |
| pass |
| |
| |
| class Connection: |
| |
| def __init__(self, url, traversal_source, |
| executor, pool, request_serializer=None, |
| response_serializer=None, auth=None, interceptors=None, |
| headers=None, enable_user_agent_on_connect=True, |
| bulk_results=False, **transport_kwargs): |
| if callable(interceptors): |
| interceptors = [interceptors] |
| elif not (isinstance(interceptors, tuple) |
| or isinstance(interceptors, list) |
| or interceptors is None): |
| raise TypeError("interceptors must be a callable, tuple, list or None") |
| |
| self._url = url |
| self._headers = headers |
| self._traversal_source = traversal_source |
| self._transport_kwargs = transport_kwargs |
| self._executor = executor |
| self._transport = None |
| self._pool = pool |
| self._result_set = None |
| self._inited = False |
| self._request_serializer = request_serializer |
| self._response_serializer = response_serializer |
| self._auth = auth |
| self._interceptors = interceptors |
| self._enable_user_agent_on_connect = enable_user_agent_on_connect |
| if self._enable_user_agent_on_connect: |
| self.__add_header(useragent.userAgentHeader, useragent.userAgent) |
| self._bulk_results = bulk_results |
| if self._bulk_results: |
| self.__add_header("bulkResults", "true") |
| |
| def connect(self): |
| if self._transport: |
| self._transport.close() |
| self._transport = AiohttpHTTPTransport(**self._transport_kwargs) |
| self._transport.connect(self._url, self._headers) |
| self._inited = True |
| |
| def close(self): |
| if self._inited: |
| self._transport.close() |
| |
| def _write_request(self, request_message): |
| accept = str(self._response_serializer.version, encoding='utf-8') |
| message = { |
| 'headers': {'accept': accept}, |
| 'payload': self._request_serializer.serialize_message(request_message) |
| if self._request_serializer is not None else request_message, |
| 'auth': self._auth |
| } |
| if self._request_serializer is not None: |
| content_type = str(self._request_serializer.version, encoding='utf-8') |
| message['headers']['content-type'] = content_type |
| # Promote transactionId to HTTP header before interceptors run. |
| # The field remains in the serialized body as well (dual transmission |
| # per the HTTP transaction protocol specification). |
| if hasattr(request_message, 'fields') and 'transactionId' in request_message.fields: |
| message['headers']['X-Transaction-Id'] = request_message.fields['transactionId'] |
| for interceptor in self._interceptors or []: |
| message = interceptor(message) |
| self._transport.write(message) |
| |
| def write(self, request_message): |
| if not self._inited: |
| self.connect() |
| self._result_set = resultset.ResultSet(queue.Queue()) |
| # Create write task |
| future = Future() |
| future_write = self._executor.submit( |
| self._write_request, request_message) |
| |
| def cb(f): |
| try: |
| f.result() |
| except _TRANSPORT_ERRORS as e: |
| wrapped = GremlinConnectionError(_CONNECTION_ERROR_MSG) |
| wrapped.__cause__ = e |
| future.set_exception(wrapped) |
| self._pool.put_nowait(self) |
| except Exception as e: |
| future.set_exception(e) |
| self._pool.put_nowait(self) |
| else: |
| # Start receive task |
| done = self._executor.submit(self._receive) |
| self._result_set.done = done |
| future.set_result(self._result_set) |
| |
| future_write.add_done_callback(cb) |
| return future |
| |
| def _receive(self): |
| try: |
| # Surface error responses whose Content-Type doesn't match the |
| # configured response serializer (e.g. plain-text 5xx). |
| status = getattr(self._transport, 'status_code', None) |
| response_content_type = str(self._response_serializer.version, encoding='utf-8') |
| if status is not None and status >= 400: |
| content_type = getattr(self._transport, 'content_type', '') |
| if response_content_type not in content_type: |
| body = self._transport.read_body().decode('utf-8', errors='replace') |
| raise GremlinServerError({ |
| 'code': status, |
| 'message': body, |
| 'exception': '' |
| }) |
| |
| # 204 No Content |
| if status == 204: |
| return |
| |
| # Stream items through the configured response serializer; it |
| # raises GremlinServerError if the response ends with a non-success status. |
| stream = self._transport.get_stream() |
| for obj in self._response_serializer.deserialize_response_stream(stream): |
| self._result_set.stream.put_nowait(obj) |
| except _TRANSPORT_ERRORS as err: |
| # Release the response to evict the dead connection from aiohttp's |
| # internal pool, ensuring subsequent requests get a fresh connection. |
| self._transport.release_response() |
| msg = 'Server returned an empty response body' if isinstance(err, asyncio.IncompleteReadError) and not err.partial else _CONNECTION_ERROR_MSG |
| raise GremlinConnectionError(msg) from err |
| except Exception: |
| self._transport.release_response() |
| raise |
| finally: |
| self._pool.put_nowait(self) |
| |
| def __add_header(self, key, value): |
| if self._headers is None: |
| self._headers = dict() |
| # Headers may be a list of pairs |
| if isinstance(self._headers, list): |
| for pair in self._headers: |
| if pair[0] == key: |
| self._headers.remove(pair) |
| self._headers.append((key, value)) |
| else: |
| self._headers[key] = value |
