This file is indexed.

/usr/lib/python2.7/dist-packages/pymongo/topology.py is in python-pymongo 3.4.0-1.

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
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
# Copyright 2014-2016 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
import weakref

from bson.py3compat import itervalues, PY3
if PY3:
    import queue as Queue
else:
    import Queue

from pymongo import common
from pymongo import periodic_executor
from pymongo.pool import PoolOptions
from pymongo.topology_description import (updated_topology_description,
                                          TOPOLOGY_TYPE,
                                          TopologyDescription)
from pymongo.errors import ServerSelectionTimeoutError
from pymongo.monotonic import time as _time
from pymongo.server import Server
from pymongo.server_selectors import (any_server_selector,
                                      arbiter_server_selector,
                                      secondary_server_selector,
                                      writable_server_selector,
                                      Selection)


def process_events_queue(queue_ref):
    q = queue_ref()
    if not q:
        return False  # Cancel PeriodicExecutor.

    while True:
        try:
            event = q.get_nowait()
        except Queue.Empty:
            break
        else:
            fn, args = event
            fn(*args)

    return True  # Continue PeriodicExecutor.


class Topology(object):
    """Monitor a topology of one or more servers."""
    def __init__(self, topology_settings):
        self._topology_id = topology_settings._topology_id
        self._listeners = topology_settings._pool_options.event_listeners
        pub = self._listeners is not None
        self._publish_server = pub and self._listeners.enabled_for_server
        self._publish_tp = pub and self._listeners.enabled_for_topology

        # Create events queue if there are publishers.
        self._events = None
        self._events_thread = None

        if self._publish_server or self._publish_tp:
            self._events = Queue.Queue(maxsize=100)

        if self._publish_tp:
            self._events.put((self._listeners.publish_topology_opened,
                             (self._topology_id,)))
        self._settings = topology_settings
        topology_description = TopologyDescription(
            topology_settings.get_topology_type(),
            topology_settings.get_server_descriptions(),
            topology_settings.replica_set_name,
            None,
            None,
            topology_settings)

        self._description = topology_description
        if self._publish_tp:
            initial_td = TopologyDescription(TOPOLOGY_TYPE.Unknown, {}, None,
                                             None, None, self._settings)
            self._events.put((
                self._listeners.publish_topology_description_changed,
                (initial_td, self._description, self._topology_id)))

        for seed in topology_settings.seeds:
            if self._publish_server:
                self._events.put((self._listeners.publish_server_opened,
                                 (seed, self._topology_id)))

        # 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

        if self._publish_server or self._publish_tp:
            def target():
                return process_events_queue(weak)

            executor = periodic_executor.PeriodicExecutor(
                interval=common.EVENTS_QUEUE_FREQUENCY,
                min_interval=0.5,
                target=target,
                name="pymongo_events_thread")

            # We strongly reference the executor and it weakly references
            # the queue via this closure. When the topology is freed, stop
            # the executor soon.
            weak = weakref.ref(self._events)
            self.__events_executor = executor
            executor.open()

    def open(self):
        """Start monitoring, or restart after a fork.

        No effect if called multiple times.

        .. warning:: Topology is shared among multiple threads and is protected
          by mutual exclusion. Using Topology from a process other than the one
          that initialized it will emit a warning and may result in deadlock. To
          prevent this from happening, MongoClient must be created after any
          forking OR MongoClient must be started with connect=False.

        """
        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#pymongo-fork-safe>")

        with self._lock:
            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._description.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._description.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):
                td_old = self._description
                if self._publish_server:
                    old_server_description = td_old._server_descriptions[
                        server_description.address]
                    self._events.put((
                        self._listeners.publish_server_description_changed,
                        (old_server_description, server_description,
                         server_description.address, self._topology_id)))

                self._description = updated_topology_description(
                    self._description, server_description)

                self._update_servers()

                if self._publish_tp:
                    self._events.put((
                        self._listeners.publish_topology_description_changed,
                        (td_old, self._description, self._topology_id)))

                # 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

            return writable_server_selector(self._new_selection())[0].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()

            return set([sd.address for sd in selector(self._new_selection())])

    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 update_pool(self):
        # Remove any stale sockets and add new sockets if pool is too small.
        with self._lock:
            for server in self._servers.values():
                server._pool.remove_stale_sockets()

    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()
        # Publish only after releasing the lock.
        if self._publish_tp:
            self._events.put((self._listeners.publish_topology_closed,
                              (self._topology_id,)))
        if self._publish_server or self._publish_tp:
            self.__events_executor.close()

    @property
    def description(self):
        return self._description

    def _new_selection(self):
        """A Selection object, initially including all known servers.

        Hold the lock when calling this.
        """
        return Selection.from_topology_description(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()

            # Start or restart the events publishing thread.
            if self._publish_tp or self._publish_server:
                self.__events_executor.open()
        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 _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)

                weak = None
                if self._publish_server:
                    weak = weakref.ref(self._events)
                server = Server(
                    server_description=sd,
                    pool=self._create_pool_for_server(address),
                    monitor=monitor,
                    topology_id=self._topology_id,
                    listeners=self._listeners,
                    events=weak)

                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,
            event_listeners=options.event_listeners,
            appname=options.appname)

        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)