forked from mongodb/mongo-python-driver
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathcommand_cursor.py
More file actions
245 lines (200 loc) · 8.4 KB
/
command_cursor.py
File metadata and controls
245 lines (200 loc) · 8.4 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
# Copyright 2014-2015 MongoDB, Inc.
#
# Licensed 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.
"""CommandCursor class to iterate over command results."""
import datetime
from collections import deque
from bson.py3compat import integer_types
from pymongo import helpers
from pymongo.errors import AutoReconnect, NotMasterError, OperationFailure
from pymongo.message import _CursorAddress, _GetMore, _convert_exception
class CommandCursor(object):
"""A cursor / iterator over command cursors.
"""
def __init__(self, collection, cursor_info, address, retrieved=0):
"""Create a new command cursor.
"""
self.__collection = collection
self.__id = cursor_info['id']
self.__address = address
self.__data = deque(cursor_info['firstBatch'])
self.__retrieved = retrieved
self.__batch_size = 0
self.__killed = (self.__id == 0)
if "ns" in cursor_info:
self.__ns = cursor_info["ns"]
else:
self.__ns = collection.full_name
def __del__(self):
if self.__id and not self.__killed:
self.__die()
def __die(self):
"""Closes this cursor.
"""
if self.__id and not self.__killed:
self.__collection.database.client.close_cursor(
self.__id, _CursorAddress(self.__address, self.__ns))
self.__killed = True
def close(self):
"""Explicitly close / kill this cursor. Required for PyPy, Jython and
other Python implementations that don't use reference counting
garbage collection.
"""
self.__die()
def batch_size(self, batch_size):
"""Limits the number of documents returned in one batch. Each batch
requires a round trip to the server. It can be adjusted to optimize
performance and limit data transfer.
.. note:: batch_size can not override MongoDB's internal limits on the
amount of data it will return to the client in a single batch (i.e
if you set batch size to 1,000,000,000, MongoDB will currently only
return 4-16MB of results per batch).
Raises :exc:`TypeError` if `batch_size` is not an integer.
Raises :exc:`ValueError` if `batch_size` is less than ``0``.
:Parameters:
- `batch_size`: The size of each batch of results requested.
"""
if not isinstance(batch_size, integer_types):
raise TypeError("batch_size must be an integer")
if batch_size < 0:
raise ValueError("batch_size must be >= 0")
self.__batch_size = batch_size == 1 and 2 or batch_size
return self
def __send_message(self, operation):
"""Send a getmore message and handle the response.
"""
client = self.__collection.database.client
listeners = client._event_listeners
publish = listeners.enabled_for_commands
try:
response = client._send_message_with_response(
operation, address=self.__address)
except AutoReconnect:
# Don't try to send kill cursors on another socket
# or to another server. It can cause a _pinValue
# assertion on some server releases if we get here
# due to a socket timeout.
self.__killed = True
raise
cmd_duration = response.duration
rqst_id = response.request_id
from_command = response.from_command
if publish:
start = datetime.datetime.now()
try:
doc = helpers._unpack_response(response.data,
self.__id,
self.__collection.codec_options)
if from_command:
helpers._check_command_response(doc['data'][0])
except OperationFailure as exc:
self.__killed = True
if publish:
duration = (datetime.datetime.now() - start) + cmd_duration
listeners.publish_command_failure(
duration, exc.details, "getMore", rqst_id, self.__address)
raise
except NotMasterError as exc:
# Don't send kill cursors to another server after a "not master"
# error. It's completely pointless.
self.__killed = True
if publish:
duration = (datetime.datetime.now() - start) + cmd_duration
listeners.publish_command_failure(
duration, exc.details, "getMore", rqst_id, self.__address)
client._reset_server_and_request_check(self.address)
raise
except Exception as exc:
if publish:
duration = (datetime.datetime.now() - start) + cmd_duration
listeners.publish_command_failure(
duration, _convert_exception(exc), "getMore", rqst_id,
self.__address)
raise
if from_command:
cursor = doc['data'][0]['cursor']
documents = cursor['nextBatch']
self.__id = cursor['id']
self.__retrieved += len(documents)
else:
documents = doc["data"]
self.__id = doc["cursor_id"]
self.__retrieved += doc["number_returned"]
if publish:
duration = (datetime.datetime.now() - start) + cmd_duration
# Must publish in getMore command response format.
res = {"cursor": {"id": self.__id,
"ns": self.__collection.full_name,
"nextBatch": documents},
"ok": 1}
listeners.publish_command_success(
duration, res, "getMore", rqst_id, self.__address)
if self.__id == 0:
self.__killed = True
self.__data = deque(documents)
def _refresh(self):
"""Refreshes the cursor with more data from the server.
Returns the length of self.__data after refresh. Will exit early if
self.__data is already non-empty. Raises OperationFailure when the
cursor cannot be refreshed due to an error on the query.
"""
if len(self.__data) or self.__killed:
return len(self.__data)
if self.__id: # Get More
dbname, collname = self.__ns.split('.', 1)
self.__send_message(
_GetMore(dbname,
collname,
self.__batch_size,
self.__id,
self.__collection.codec_options))
else: # Cursor id is zero nothing else to return
self.__killed = True
return len(self.__data)
@property
def alive(self):
"""Does this cursor have the potential to return more data?
Even if :attr:`alive` is ``True``, :meth:`next` can raise
:exc:`StopIteration`. Best to use a for loop::
for doc in collection.aggregate(pipeline):
print(doc)
.. note:: :attr:`alive` can be True while iterating a cursor from
a failed server. In this case :attr:`alive` will return False after
:meth:`next` fails to retrieve the next batch of results from the
server.
"""
return bool(len(self.__data) or (not self.__killed))
@property
def cursor_id(self):
"""Returns the id of the cursor."""
return self.__id
@property
def address(self):
"""The (host, port) of the server used, or None.
.. versionadded:: 3.0
"""
return self.__address
def __iter__(self):
return self
def next(self):
"""Advance the cursor."""
if len(self.__data) or self._refresh():
coll = self.__collection
return coll.database._fix_outgoing(self.__data.popleft(), coll)
else:
raise StopIteration
__next__ = next
def __enter__(self):
return self
def __exit__(self, exc_type, exc_val, exc_tb):
self.__die()