/usr/lib/python3/dist-packages/pymongo/topology.py is in python3-pymongo 3.2-1build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 | # 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.
"""Internal class to monitor a topology of one or more servers."""
import os
import random
import threading
import warnings
from bson.py3compat import itervalues
from pymongo import common
from pymongo.pool import PoolOptions
from pymongo.topology_description import (updated_topology_description,
TOPOLOGY_TYPE,
TopologyDescription)
from pymongo.errors import ServerSelectionTimeoutError, InvalidOperation
from pymongo.monotonic import time as _time
from pymongo.server import Server
from pymongo.server_selectors import (any_server_selector,
apply_local_threshold,
arbiter_server_selector,
secondary_server_selector,
writable_server_selector)
class Topology(object):
"""Monitor a topology of one or more servers."""
def __init__(self, topology_settings):
self._settings = topology_settings
topology_description = TopologyDescription(
topology_settings.get_topology_type(),
topology_settings.get_server_descriptions(),
topology_settings.replica_set_name,
None)
self._description = topology_description
# Store the seed list to help diagnose errors in _error_message().
self._seed_addresses = list(topology_description.server_descriptions())
self._opened = False
self._lock = threading.Lock()
self._condition = self._settings.condition_class(self._lock)
self._servers = {}
self._pid = None
def open(self):
"""Start monitoring, or restart after a fork.
No effect if called multiple times.
.. warning:: To avoid a deadlock during Python's getaddrinfo call,
will generate a warning if open() is called from a different
process than the one that initialized the Topology. To prevent this
from happening, MongoClient must be created after any forking OR
MongoClient must be started with connect=False.
"""
with self._lock:
if self._pid is None:
self._pid = os.getpid()
else:
if os.getpid() != self._pid:
warnings.warn(
"MongoClient opened before fork. Create MongoClient "
"with connect=False, or create client after forking. "
"See PyMongo's documentation for details: http://api."
"mongodb.org/python/current/faq.html#using-pymongo-"
"with-multiprocessing>")
self._ensure_opened()
def select_servers(self,
selector,
server_selection_timeout=None,
address=None):
"""Return a list of Servers matching selector, or time out.
:Parameters:
- `selector`: function that takes a list of Servers and returns
a subset of them.
- `server_selection_timeout` (optional): maximum seconds to wait.
If not provided, the default value common.SERVER_SELECTION_TIMEOUT
is used.
- `address`: optional server address to select.
Calls self.open() if needed.
Raises exc:`ServerSelectionTimeoutError` after
`server_selection_timeout` if no matching servers are found.
"""
if server_selection_timeout is None:
server_timeout = self._settings.server_selection_timeout
else:
server_timeout = server_selection_timeout
with self._lock:
self._description.check_compatible()
now = _time()
end_time = now + server_timeout
server_descriptions = self._apply_selector(selector, address)
while not server_descriptions:
# No suitable servers.
if server_timeout == 0 or now > end_time:
raise ServerSelectionTimeoutError(
self._error_message(selector))
self._ensure_opened()
self._request_check_all()
# Release the lock and wait for the topology description to
# change, or for a timeout. We won't miss any changes that
# came after our most recent _apply_selector call, since we've
# held the lock until now.
self._condition.wait(common.MIN_HEARTBEAT_INTERVAL)
self._description.check_compatible()
now = _time()
server_descriptions = self._apply_selector(selector, address)
return [self.get_server_by_address(sd.address)
for sd in server_descriptions]
def select_server(self,
selector,
server_selection_timeout=None,
address=None):
"""Like select_servers, but choose a random server if several match."""
return random.choice(self.select_servers(selector,
server_selection_timeout,
address))
def select_server_by_address(self, address,
server_selection_timeout=None):
"""Return a Server for "address", reconnecting if necessary.
If the server's type is not known, request an immediate check of all
servers. Time out after "server_selection_timeout" if the server
cannot be reached.
:Parameters:
- `address`: A (host, port) pair.
- `server_selection_timeout` (optional): maximum seconds to wait.
If not provided, the default value
common.SERVER_SELECTION_TIMEOUT is used.
Calls self.open() if needed.
Raises exc:`ServerSelectionTimeoutError` after
`server_selection_timeout` if no matching servers are found.
"""
return self.select_server(any_server_selector,
server_selection_timeout,
address)
def on_change(self, server_description):
"""Process a new ServerDescription after an ismaster call completes."""
# We do no I/O holding the lock.
with self._lock:
# Any monitored server was definitely in the topology description
# once. Check if it's still in the description or if some state-
# change removed it. E.g., we got a host list from the primary
# that didn't include this server.
if self._description.has_server(server_description.address):
self._description = updated_topology_description(
self._description, server_description)
self._update_servers()
# Wake waiters in select_servers().
self._condition.notify_all()
def get_server_by_address(self, address):
"""Get a Server or None.
Returns the current version of the server immediately, even if it's
Unknown or absent from the topology. Only use this in unittests.
In driver code, use select_server_by_address, since then you're
assured a recent view of the server's type and wire protocol version.
"""
return self._servers.get(address)
def has_server(self, address):
return address in self._servers
def get_primary(self):
"""Return primary's address or None."""
# Implemented here in Topology instead of MongoClient, so it can lock.
with self._lock:
topology_type = self._description.topology_type
if topology_type != TOPOLOGY_TYPE.ReplicaSetWithPrimary:
return None
description = writable_server_selector(
self._description.known_servers)[0]
return description.address
def _get_replica_set_members(self, selector):
"""Return set of replica set member addresses."""
# Implemented here in Topology instead of MongoClient, so it can lock.
with self._lock:
topology_type = self._description.topology_type
if topology_type not in (TOPOLOGY_TYPE.ReplicaSetWithPrimary,
TOPOLOGY_TYPE.ReplicaSetNoPrimary):
return set()
descriptions = selector(self._description.known_servers)
return set([d.address for d in descriptions])
def get_secondaries(self):
"""Return set of secondary addresses."""
return self._get_replica_set_members(secondary_server_selector)
def get_arbiters(self):
"""Return set of arbiter addresses."""
return self._get_replica_set_members(arbiter_server_selector)
def request_check_all(self, wait_time=5):
"""Wake all monitors, wait for at least one to check its server."""
with self._lock:
self._request_check_all()
self._condition.wait(wait_time)
def reset_pool(self, address):
with self._lock:
server = self._servers.get(address)
if server:
server.pool.reset()
def reset_server(self, address):
"""Clear our pool for a server and mark it Unknown.
Do *not* request an immediate check.
"""
with self._lock:
self._reset_server(address)
def reset_server_and_request_check(self, address):
"""Clear our pool for a server, mark it Unknown, and check it soon."""
with self._lock:
self._reset_server(address)
self._request_check(address)
def close(self):
"""Clear pools and terminate monitors. Topology reopens on demand."""
with self._lock:
for server in self._servers.values():
server.close()
# Mark all servers Unknown.
self._description = self._description.reset()
self._update_servers()
@property
def description(self):
return self._description
def _ensure_opened(self):
"""Start monitors, or restart after a fork.
Hold the lock when calling this.
"""
if not self._opened:
self._opened = True
self._update_servers()
else:
# Restart monitors if we forked since previous call.
for server in itervalues(self._servers):
server.open()
def _reset_server(self, address):
"""Clear our pool for a server and mark it Unknown.
Hold the lock when calling this. Does *not* request an immediate check.
"""
server = self._servers.get(address)
# "server" is None if another thread removed it from the topology.
if server:
server.reset()
# Mark this server Unknown.
self._description = self._description.reset_server(address)
self._update_servers()
def _request_check(self, address):
"""Wake one monitor. Hold the lock when calling this."""
server = self._servers.get(address)
# "server" is None if another thread removed it from the topology.
if server:
server.request_check()
def _request_check_all(self):
"""Wake all monitors. Hold the lock when calling this."""
for server in self._servers.values():
server.request_check()
def _apply_selector(self, selector, address):
if self._description.topology_type == TOPOLOGY_TYPE.Single:
# Ignore the selector.
return self._description.known_servers
elif address:
sd = self._description.server_descriptions().get(address)
return [sd] if sd else []
elif self._description.topology_type == TOPOLOGY_TYPE.Sharded:
return apply_local_threshold(self._settings.local_threshold_ms,
self._description.known_servers)
else:
sds = selector(self._description.known_servers)
return apply_local_threshold(
self._settings.local_threshold_ms, sds)
def _update_servers(self):
"""Sync our Servers from TopologyDescription.server_descriptions.
Hold the lock while calling this.
"""
for address, sd in self._description.server_descriptions().items():
if address not in self._servers:
monitor = self._settings.monitor_class(
server_description=sd,
topology=self,
pool=self._create_pool_for_monitor(address),
topology_settings=self._settings)
server = Server(
server_description=sd,
pool=self._create_pool_for_server(address),
monitor=monitor)
self._servers[address] = server
server.open()
else:
self._servers[address].description = sd
for address, server in list(self._servers.items()):
if not self._description.has_server(address):
server.close()
self._servers.pop(address)
def _create_pool_for_server(self, address):
return self._settings.pool_class(address, self._settings.pool_options)
def _create_pool_for_monitor(self, address):
options = self._settings.pool_options
# According to the Server Discovery And Monitoring Spec, monitors use
# connect_timeout for both connect_timeout and socket_timeout. The
# pool only has one socket so maxPoolSize and so on aren't needed.
monitor_pool_options = PoolOptions(
connect_timeout=options.connect_timeout,
socket_timeout=options.connect_timeout,
ssl_context=options.ssl_context,
ssl_match_hostname=options.ssl_match_hostname,
socket_keepalive=True)
return self._settings.pool_class(address, monitor_pool_options,
handshake=False)
def _error_message(self, selector):
"""Format an error message if server selection fails.
Hold the lock when calling this.
"""
is_replica_set = self._description.topology_type in (
TOPOLOGY_TYPE.ReplicaSetWithPrimary,
TOPOLOGY_TYPE.ReplicaSetNoPrimary)
if is_replica_set:
server_plural = 'replica set members'
elif self._description.topology_type == TOPOLOGY_TYPE.Sharded:
server_plural = 'mongoses'
else:
server_plural = 'servers'
if self._description.known_servers:
# We've connected, but no servers match the selector.
if selector is writable_server_selector:
if is_replica_set:
return 'No primary available for writes'
else:
return 'No %s available for writes' % server_plural
else:
return 'No %s match selector "%s"' % (server_plural, selector)
else:
addresses = list(self._description.server_descriptions())
servers = list(self._description.server_descriptions().values())
if not servers:
if is_replica_set:
# We removed all servers because of the wrong setName?
return 'No %s available for replica set name "%s"' % (
server_plural, self._settings.replica_set_name)
else:
return 'No %s available' % server_plural
# 1 or more servers, all Unknown. Are they unknown for one reason?
error = servers[0].error
same = all(server.error == error for server in servers[1:])
if same:
if error is None:
# We're still discovering.
return 'No %s found yet' % server_plural
if (is_replica_set and not
set(addresses).intersection(self._seed_addresses)):
# We replaced our seeds with new hosts but can't reach any.
return (
'Could not reach any servers in %s. Replica set is'
' configured with internal hostnames or IPs?' %
addresses)
return str(error)
else:
return ','.join(str(server.error) for server in servers
if server.error)
|