/usr/lib/python3/dist-packages/pymongo/server_selectors.py is in python3-pymongo 3.2-1build1.
This file is owned by root:root, with mode 0o644.
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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 | # 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.
"""Criteria to select some ServerDescriptions out of a list."""
from pymongo.server_type import SERVER_TYPE
def any_server_selector(server_descriptions):
return server_descriptions
def readable_server_selector(server_descriptions):
return [s for s in server_descriptions if s.is_readable]
def writable_server_selector(server_descriptions):
return [s for s in server_descriptions if s.is_writable]
def secondary_server_selector(server_descriptions):
return [s for s in server_descriptions
if s.server_type == SERVER_TYPE.RSSecondary]
def arbiter_server_selector(server_descriptions):
return [s for s in server_descriptions
if s.server_type == SERVER_TYPE.RSArbiter]
def writable_preferred_server_selector(server_descriptions):
"""Like PrimaryPreferred but doesn't use tags or latency."""
return (
writable_server_selector(server_descriptions) or
secondary_server_selector(server_descriptions))
def single_tag_set_server_selector(tag_set, server_descriptions):
"""All servers matching one tag set.
A tag set is a dict. A server matches if its tags are a superset:
A server tagged {'a': '1', 'b': '2'} matches the tag set {'a': '1'}.
The empty tag set {} matches any server.
The `server_descriptions` passed to this function should have
non-readable servers (e.g. RSGhost, RSArbiter, Unknown) filtered
out (e.g. by readable_server_selector or secondary_server_selector)
first.
"""
def tags_match(server_tags):
for key, value in tag_set.items():
if key not in server_tags or server_tags[key] != value:
return False
return True
return [s for s in server_descriptions if tags_match(s.tags)]
def tag_sets_server_selector(tag_sets, server_descriptions):
"""All servers match a list of tag sets.
tag_sets is a list of dicts. The empty tag set {} matches any server,
and may be provided at the end of the list as a fallback. So
[{'a': 'value'}, {}] expresses a preference for servers tagged
{'a': 'value'}, but accepts any server if none matches the first
preference.
The `server_descriptions` passed to this function should have
non-readable servers (e.g. RSGhost, RSArbiter, Unknown) filtered
out (e.g. by readable_server_selector or secondary_server_selector)
first.
"""
for tag_set in tag_sets:
selected = single_tag_set_server_selector(tag_set, server_descriptions)
if selected:
return selected
return []
def apply_local_threshold(latency_ms, server_descriptions):
"""All servers with round trip times within latency_ms of the fastest one.
No ServerDescription's round_trip_time can be None.
The `server_descriptions` passed to this function should have
non-readable servers (e.g. RSGhost, RSArbiter, Unknown) filtered
out (e.g. by readable_server_selector or secondary_server_selector)
first.
"""
if not server_descriptions:
# Avoid ValueError from min() with empty sequence.
return []
# round_trip_time is in seconds.
if any(s for s in server_descriptions if s.round_trip_time is None):
raise ValueError("Not all servers' round trip times are known")
fastest = min(s.round_trip_time for s in server_descriptions)
return [
s for s in server_descriptions
if (s.round_trip_time - fastest) <= latency_ms / 1000.]
def secondary_with_tags_server_selector(tag_sets, server_descriptions):
"""All near-enough secondaries matching the tag sets."""
return tag_sets_server_selector(
tag_sets, secondary_server_selector(server_descriptions))
def member_with_tags_server_selector(tag_sets, server_descriptions):
"""All near-enough members matching the tag sets."""
return tag_sets_server_selector(
tag_sets, readable_server_selector(server_descriptions))
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