312 lines
12 KiB
Python
312 lines
12 KiB
Python
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# Copyright 2015-present MongoDB, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Internal network layer helper methods."""
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import datetime
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import errno
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import socket
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import struct
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import time
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from bson import _decode_all_selective
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from pymongo import _csot, helpers, message, ssl_support
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from pymongo.common import MAX_MESSAGE_SIZE
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from pymongo.compression_support import _NO_COMPRESSION, decompress
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from pymongo.errors import (
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NotPrimaryError,
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OperationFailure,
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ProtocolError,
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_OperationCancelled,
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)
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from pymongo.message import _UNPACK_REPLY, _OpMsg
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from pymongo.monitoring import _is_speculative_authenticate
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from pymongo.socket_checker import _errno_from_exception
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_UNPACK_HEADER = struct.Struct("<iiii").unpack
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def command(
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sock_info,
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dbname,
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spec,
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is_mongos,
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read_preference,
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codec_options,
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session,
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client,
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check=True,
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allowable_errors=None,
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address=None,
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listeners=None,
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max_bson_size=None,
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read_concern=None,
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parse_write_concern_error=False,
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collation=None,
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compression_ctx=None,
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use_op_msg=False,
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unacknowledged=False,
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user_fields=None,
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exhaust_allowed=False,
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write_concern=None,
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):
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"""Execute a command over the socket, or raise socket.error.
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:Parameters:
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- `sock`: a raw socket instance
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- `dbname`: name of the database on which to run the command
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- `spec`: a command document as an ordered dict type, eg SON.
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- `is_mongos`: are we connected to a mongos?
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- `read_preference`: a read preference
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- `codec_options`: a CodecOptions instance
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- `session`: optional ClientSession instance.
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- `client`: optional MongoClient instance for updating $clusterTime.
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- `check`: raise OperationFailure if there are errors
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- `allowable_errors`: errors to ignore if `check` is True
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- `address`: the (host, port) of `sock`
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- `listeners`: An instance of :class:`~pymongo.monitoring.EventListeners`
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- `max_bson_size`: The maximum encoded bson size for this server
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- `read_concern`: The read concern for this command.
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- `parse_write_concern_error`: Whether to parse the ``writeConcernError``
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field in the command response.
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- `collation`: The collation for this command.
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- `compression_ctx`: optional compression Context.
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- `use_op_msg`: True if we should use OP_MSG.
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- `unacknowledged`: True if this is an unacknowledged command.
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- `user_fields` (optional): Response fields that should be decoded
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using the TypeDecoders from codec_options, passed to
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bson._decode_all_selective.
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- `exhaust_allowed`: True if we should enable OP_MSG exhaustAllowed.
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"""
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name = next(iter(spec))
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ns = dbname + ".$cmd"
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speculative_hello = False
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# Publish the original command document, perhaps with lsid and $clusterTime.
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orig = spec
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if is_mongos and not use_op_msg:
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spec = message._maybe_add_read_preference(spec, read_preference)
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if read_concern and not (session and session.in_transaction):
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if read_concern.level:
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spec["readConcern"] = read_concern.document
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if session:
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session._update_read_concern(spec, sock_info)
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if collation is not None:
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spec["collation"] = collation
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publish = listeners is not None and listeners.enabled_for_commands
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if publish:
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start = datetime.datetime.now()
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speculative_hello = _is_speculative_authenticate(name, spec)
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if compression_ctx and name.lower() in _NO_COMPRESSION:
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compression_ctx = None
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if client and client._encrypter and not client._encrypter._bypass_auto_encryption:
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spec = orig = client._encrypter.encrypt(dbname, spec, codec_options)
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# Support CSOT
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if client:
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sock_info.apply_timeout(client, spec)
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_csot.apply_write_concern(spec, write_concern)
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if use_op_msg:
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flags = _OpMsg.MORE_TO_COME if unacknowledged else 0
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flags |= _OpMsg.EXHAUST_ALLOWED if exhaust_allowed else 0
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request_id, msg, size, max_doc_size = message._op_msg(
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flags, spec, dbname, read_preference, codec_options, ctx=compression_ctx
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)
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# If this is an unacknowledged write then make sure the encoded doc(s)
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# are small enough, otherwise rely on the server to return an error.
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if unacknowledged and max_bson_size is not None and max_doc_size > max_bson_size:
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message._raise_document_too_large(name, size, max_bson_size)
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else:
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request_id, msg, size = message._query(
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0, ns, 0, -1, spec, None, codec_options, compression_ctx
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)
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if max_bson_size is not None and size > max_bson_size + message._COMMAND_OVERHEAD:
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message._raise_document_too_large(name, size, max_bson_size + message._COMMAND_OVERHEAD)
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if publish:
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encoding_duration = datetime.datetime.now() - start
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listeners.publish_command_start(
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orig, dbname, request_id, address, service_id=sock_info.service_id
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)
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start = datetime.datetime.now()
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try:
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sock_info.sock.sendall(msg)
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if use_op_msg and unacknowledged:
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# Unacknowledged, fake a successful command response.
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reply = None
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response_doc = {"ok": 1}
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else:
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reply = receive_message(sock_info, request_id)
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sock_info.more_to_come = reply.more_to_come
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unpacked_docs = reply.unpack_response(
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codec_options=codec_options, user_fields=user_fields
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)
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response_doc = unpacked_docs[0]
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if client:
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client._process_response(response_doc, session)
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if check:
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helpers._check_command_response(
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response_doc,
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sock_info.max_wire_version,
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allowable_errors,
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parse_write_concern_error=parse_write_concern_error,
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)
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except Exception as exc:
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if publish:
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duration = (datetime.datetime.now() - start) + encoding_duration
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if isinstance(exc, (NotPrimaryError, OperationFailure)):
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failure = exc.details
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else:
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failure = message._convert_exception(exc)
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listeners.publish_command_failure(
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duration, failure, name, request_id, address, service_id=sock_info.service_id
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)
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raise
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if publish:
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duration = (datetime.datetime.now() - start) + encoding_duration
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listeners.publish_command_success(
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duration,
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response_doc,
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name,
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request_id,
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address,
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service_id=sock_info.service_id,
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speculative_hello=speculative_hello,
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)
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if client and client._encrypter and reply:
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decrypted = client._encrypter.decrypt(reply.raw_command_response())
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response_doc = _decode_all_selective(decrypted, codec_options, user_fields)[0]
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return response_doc
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_UNPACK_COMPRESSION_HEADER = struct.Struct("<iiB").unpack
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def receive_message(sock_info, request_id, max_message_size=MAX_MESSAGE_SIZE):
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"""Receive a raw BSON message or raise socket.error."""
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if _csot.get_timeout():
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deadline = _csot.get_deadline()
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else:
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timeout = sock_info.sock.gettimeout()
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if timeout:
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deadline = time.monotonic() + timeout
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else:
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deadline = None
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# Ignore the response's request id.
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length, _, response_to, op_code = _UNPACK_HEADER(
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_receive_data_on_socket(sock_info, 16, deadline)
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)
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# No request_id for exhaust cursor "getMore".
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if request_id is not None:
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if request_id != response_to:
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raise ProtocolError(f"Got response id {response_to!r} but expected {request_id!r}")
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if length <= 16:
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raise ProtocolError(
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f"Message length ({length!r}) not longer than standard message header size (16)"
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)
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if length > max_message_size:
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raise ProtocolError(
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"Message length ({!r}) is larger than server max "
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"message size ({!r})".format(length, max_message_size)
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)
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if op_code == 2012:
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op_code, _, compressor_id = _UNPACK_COMPRESSION_HEADER(
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_receive_data_on_socket(sock_info, 9, deadline)
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)
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data = decompress(_receive_data_on_socket(sock_info, length - 25, deadline), compressor_id)
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else:
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data = _receive_data_on_socket(sock_info, length - 16, deadline)
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try:
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unpack_reply = _UNPACK_REPLY[op_code]
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except KeyError:
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raise ProtocolError(f"Got opcode {op_code!r} but expected {_UNPACK_REPLY.keys()!r}")
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return unpack_reply(data)
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_POLL_TIMEOUT = 0.5
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def wait_for_read(sock_info, deadline):
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"""Block until at least one byte is read, or a timeout, or a cancel."""
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context = sock_info.cancel_context
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# Only Monitor connections can be cancelled.
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if context:
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sock = sock_info.sock
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timed_out = False
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while True:
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# SSLSocket can have buffered data which won't be caught by select.
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if hasattr(sock, "pending") and sock.pending() > 0:
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readable = True
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else:
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# Wait up to 500ms for the socket to become readable and then
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# check for cancellation.
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if deadline:
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remaining = deadline - time.monotonic()
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# When the timeout has expired perform one final check to
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# see if the socket is readable. This helps avoid spurious
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# timeouts on AWS Lambda and other FaaS environments.
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if remaining <= 0:
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timed_out = True
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timeout = max(min(remaining, _POLL_TIMEOUT), 0)
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else:
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timeout = _POLL_TIMEOUT
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readable = sock_info.socket_checker.select(sock, read=True, timeout=timeout)
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if context.cancelled:
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raise _OperationCancelled("hello cancelled")
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if readable:
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return
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if timed_out:
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raise socket.timeout("timed out")
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# Errors raised by sockets (and TLS sockets) when in non-blocking mode.
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BLOCKING_IO_ERRORS = (BlockingIOError, *ssl_support.BLOCKING_IO_ERRORS)
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def _receive_data_on_socket(sock_info, length, deadline):
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buf = bytearray(length)
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mv = memoryview(buf)
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bytes_read = 0
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while bytes_read < length:
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try:
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wait_for_read(sock_info, deadline)
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# CSOT: Update timeout. When the timeout has expired perform one
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# final non-blocking recv. This helps avoid spurious timeouts when
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# the response is actually already buffered on the client.
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if _csot.get_timeout():
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sock_info.set_socket_timeout(max(deadline - time.monotonic(), 0))
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chunk_length = sock_info.sock.recv_into(mv[bytes_read:])
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except BLOCKING_IO_ERRORS:
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raise socket.timeout("timed out")
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except OSError as exc: # noqa: B014
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if _errno_from_exception(exc) == errno.EINTR:
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continue
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raise
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if chunk_length == 0:
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raise OSError("connection closed")
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bytes_read += chunk_length
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return mv
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