root / lib / confd / client.py @ 18337ca9
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1 | e4ccf6cd | Guido Trotter | #
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2 | e4ccf6cd | Guido Trotter | #
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3 | e4ccf6cd | Guido Trotter | |
4 | e4ccf6cd | Guido Trotter | # Copyright (C) 2009 Google Inc.
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5 | e4ccf6cd | Guido Trotter | #
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6 | e4ccf6cd | Guido Trotter | # This program is free software; you can redistribute it and/or modify
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7 | e4ccf6cd | Guido Trotter | # it under the terms of the GNU General Public License as published by
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8 | e4ccf6cd | Guido Trotter | # the Free Software Foundation; either version 2 of the License, or
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9 | e4ccf6cd | Guido Trotter | # (at your option) any later version.
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10 | e4ccf6cd | Guido Trotter | #
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11 | e4ccf6cd | Guido Trotter | # This program is distributed in the hope that it will be useful, but
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12 | e4ccf6cd | Guido Trotter | # WITHOUT ANY WARRANTY; without even the implied warranty of
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13 | e4ccf6cd | Guido Trotter | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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14 | e4ccf6cd | Guido Trotter | # General Public License for more details.
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15 | e4ccf6cd | Guido Trotter | #
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16 | e4ccf6cd | Guido Trotter | # You should have received a copy of the GNU General Public License
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17 | e4ccf6cd | Guido Trotter | # along with this program; if not, write to the Free Software
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18 | e4ccf6cd | Guido Trotter | # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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19 | e4ccf6cd | Guido Trotter | # 02110-1301, USA.
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20 | e4ccf6cd | Guido Trotter | |
21 | e4ccf6cd | Guido Trotter | |
22 | e4ccf6cd | Guido Trotter | """Ganeti confd client
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23 | e4ccf6cd | Guido Trotter |
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24 | cf7b0cc4 | Guido Trotter | Clients can use the confd client library to send requests to a group of master
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25 | cf7b0cc4 | Guido Trotter | candidates running confd. The expected usage is through the asyncore framework,
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26 | cf7b0cc4 | Guido Trotter | by sending queries, and asynchronously receiving replies through a callback.
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27 | cf7b0cc4 | Guido Trotter |
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28 | cf7b0cc4 | Guido Trotter | This way the client library doesn't ever need to "wait" on a particular answer,
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29 | cf7b0cc4 | Guido Trotter | and can proceed even if some udp packets are lost. It's up to the user to
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30 | cf7b0cc4 | Guido Trotter | reschedule queries if they haven't received responses and they need them.
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31 | cf7b0cc4 | Guido Trotter |
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32 | 69b99987 | Michael Hanselmann | Example usage::
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33 | 69b99987 | Michael Hanselmann |
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34 | cf7b0cc4 | Guido Trotter | client = ConfdClient(...) # includes callback specification
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35 | cf7b0cc4 | Guido Trotter | req = confd_client.ConfdClientRequest(type=constants.CONFD_REQ_PING)
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36 | cf7b0cc4 | Guido Trotter | client.SendRequest(req)
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37 | cf7b0cc4 | Guido Trotter | # then make sure your client calls asyncore.loop() or daemon.Mainloop.Run()
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38 | cf7b0cc4 | Guido Trotter | # ... wait ...
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39 | cf7b0cc4 | Guido Trotter | # And your callback will be called by asyncore, when your query gets a
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40 | cf7b0cc4 | Guido Trotter | # response, or when it expires.
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41 | cf7b0cc4 | Guido Trotter |
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42 | 392ca296 | Guido Trotter | You can use the provided ConfdFilterCallback to act as a filter, only passing
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43 | 392ca296 | Guido Trotter | "newer" answer to your callback, and filtering out outdated ones, or ones
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44 | 392ca296 | Guido Trotter | confirming what you already got.
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45 | 392ca296 | Guido Trotter |
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46 | e4ccf6cd | Guido Trotter | """
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47 | 69b99987 | Michael Hanselmann | |
48 | 6c881c52 | Iustin Pop | # pylint: disable-msg=E0203
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49 | 6c881c52 | Iustin Pop | |
50 | 6c881c52 | Iustin Pop | # E0203: Access to member %r before its definition, since we use
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51 | 6c881c52 | Iustin Pop | # objects.py which doesn't explicitely initialise its members
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52 | 6c881c52 | Iustin Pop | |
53 | e4ccf6cd | Guido Trotter | import time |
54 | e4ccf6cd | Guido Trotter | import random |
55 | e4ccf6cd | Guido Trotter | |
56 | e4ccf6cd | Guido Trotter | from ganeti import utils |
57 | e4ccf6cd | Guido Trotter | from ganeti import constants |
58 | e4ccf6cd | Guido Trotter | from ganeti import objects |
59 | e4ccf6cd | Guido Trotter | from ganeti import serializer |
60 | e4ccf6cd | Guido Trotter | from ganeti import daemon # contains AsyncUDPSocket |
61 | e4ccf6cd | Guido Trotter | from ganeti import errors |
62 | e4ccf6cd | Guido Trotter | from ganeti import confd |
63 | e4ccf6cd | Guido Trotter | |
64 | e4ccf6cd | Guido Trotter | |
65 | e4ccf6cd | Guido Trotter | class ConfdAsyncUDPClient(daemon.AsyncUDPSocket): |
66 | e4ccf6cd | Guido Trotter | """Confd udp asyncore client
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67 | e4ccf6cd | Guido Trotter |
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68 | e4ccf6cd | Guido Trotter | This is kept separate from the main ConfdClient to make sure it's easy to
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69 | e4ccf6cd | Guido Trotter | implement a non-asyncore based client library.
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70 | e4ccf6cd | Guido Trotter |
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71 | e4ccf6cd | Guido Trotter | """
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72 | e4ccf6cd | Guido Trotter | def __init__(self, client): |
73 | e4ccf6cd | Guido Trotter | """Constructor for ConfdAsyncUDPClient
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74 | e4ccf6cd | Guido Trotter |
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75 | e4ccf6cd | Guido Trotter | @type client: L{ConfdClient}
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76 | e4ccf6cd | Guido Trotter | @param client: client library, to pass the datagrams to
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77 | e4ccf6cd | Guido Trotter |
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78 | e4ccf6cd | Guido Trotter | """
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79 | e4ccf6cd | Guido Trotter | daemon.AsyncUDPSocket.__init__(self)
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80 | e4ccf6cd | Guido Trotter | self.client = client
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81 | e4ccf6cd | Guido Trotter | |
82 | e4ccf6cd | Guido Trotter | # this method is overriding a daemon.AsyncUDPSocket method
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83 | e4ccf6cd | Guido Trotter | def handle_datagram(self, payload, ip, port): |
84 | e4ccf6cd | Guido Trotter | self.client.HandleResponse(payload, ip, port)
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85 | e4ccf6cd | Guido Trotter | |
86 | e4ccf6cd | Guido Trotter | |
87 | e4ccf6cd | Guido Trotter | class ConfdClient: |
88 | e4ccf6cd | Guido Trotter | """Send queries to confd, and get back answers.
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89 | e4ccf6cd | Guido Trotter |
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90 | e4ccf6cd | Guido Trotter | Since the confd model works by querying multiple master candidates, and
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91 | e4ccf6cd | Guido Trotter | getting back answers, this is an asynchronous library. It can either work
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92 | e4ccf6cd | Guido Trotter | through asyncore or with your own handling.
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93 | e4ccf6cd | Guido Trotter |
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94 | e4ccf6cd | Guido Trotter | """
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95 | a3db74e4 | Guido Trotter | def __init__(self, hmac_key, peers, callback, port=None, logger=None): |
96 | e4ccf6cd | Guido Trotter | """Constructor for ConfdClient
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97 | e4ccf6cd | Guido Trotter |
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98 | e4ccf6cd | Guido Trotter | @type hmac_key: string
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99 | e4ccf6cd | Guido Trotter | @param hmac_key: hmac key to talk to confd
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100 | e4ccf6cd | Guido Trotter | @type peers: list
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101 | e4ccf6cd | Guido Trotter | @param peers: list of peer nodes
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102 | 96e03b0b | Guido Trotter | @type callback: f(L{ConfdUpcallPayload})
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103 | 96e03b0b | Guido Trotter | @param callback: function to call when getting answers
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104 | 7d20c647 | Guido Trotter | @type port: integer
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105 | 7d20c647 | Guido Trotter | @keyword port: confd port (default: use GetDaemonPort)
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106 | 69b99987 | Michael Hanselmann | @type logger: logging.Logger
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107 | a3db74e4 | Guido Trotter | @keyword logger: optional logger for internal conditions
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108 | e4ccf6cd | Guido Trotter |
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109 | e4ccf6cd | Guido Trotter | """
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110 | 96e03b0b | Guido Trotter | if not callable(callback): |
111 | 96e03b0b | Guido Trotter | raise errors.ProgrammerError("callback must be callable") |
112 | e4ccf6cd | Guido Trotter | |
113 | a5229439 | Guido Trotter | self.UpdatePeerList(peers)
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114 | e4ccf6cd | Guido Trotter | self._hmac_key = hmac_key
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115 | e4ccf6cd | Guido Trotter | self._socket = ConfdAsyncUDPClient(self) |
116 | 96e03b0b | Guido Trotter | self._callback = callback
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117 | 7d20c647 | Guido Trotter | self._confd_port = port
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118 | a3db74e4 | Guido Trotter | self._logger = logger
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119 | 96e03b0b | Guido Trotter | self._requests = {}
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120 | 96e03b0b | Guido Trotter | self._expire_requests = []
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121 | 7d20c647 | Guido Trotter | |
122 | 7d20c647 | Guido Trotter | if self._confd_port is None: |
123 | 7d20c647 | Guido Trotter | self._confd_port = utils.GetDaemonPort(constants.CONFD)
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124 | e4ccf6cd | Guido Trotter | |
125 | a5229439 | Guido Trotter | def UpdatePeerList(self, peers): |
126 | a5229439 | Guido Trotter | """Update the list of peers
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127 | a5229439 | Guido Trotter |
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128 | a5229439 | Guido Trotter | @type peers: list
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129 | a5229439 | Guido Trotter | @param peers: list of peer nodes
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130 | a5229439 | Guido Trotter |
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131 | a5229439 | Guido Trotter | """
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132 | e11ddf13 | Iustin Pop | # we are actually called from init, so:
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133 | e11ddf13 | Iustin Pop | # pylint: disable-msg=W0201
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134 | a5229439 | Guido Trotter | if not isinstance(peers, list): |
135 | a5229439 | Guido Trotter | raise errors.ProgrammerError("peers must be a list") |
136 | db169865 | Guido Trotter | # make a copy of peers, since we're going to shuffle the list, later
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137 | db169865 | Guido Trotter | self._peers = list(peers) |
138 | a5229439 | Guido Trotter | |
139 | e4ccf6cd | Guido Trotter | def _PackRequest(self, request, now=None): |
140 | e4ccf6cd | Guido Trotter | """Prepare a request to be sent on the wire.
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141 | e4ccf6cd | Guido Trotter |
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142 | e4ccf6cd | Guido Trotter | This function puts a proper salt in a confd request, puts the proper salt,
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143 | e4ccf6cd | Guido Trotter | and adds the correct magic number.
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144 | e4ccf6cd | Guido Trotter |
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145 | e4ccf6cd | Guido Trotter | """
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146 | e4ccf6cd | Guido Trotter | if now is None: |
147 | e4ccf6cd | Guido Trotter | now = time.time() |
148 | e4ccf6cd | Guido Trotter | tstamp = '%d' % now
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149 | e4ccf6cd | Guido Trotter | req = serializer.DumpSignedJson(request.ToDict(), self._hmac_key, tstamp)
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150 | e4ccf6cd | Guido Trotter | return confd.PackMagic(req)
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151 | e4ccf6cd | Guido Trotter | |
152 | e4ccf6cd | Guido Trotter | def _UnpackReply(self, payload): |
153 | e4ccf6cd | Guido Trotter | in_payload = confd.UnpackMagic(payload) |
154 | c103d7ae | Guido Trotter | (dict_answer, salt) = serializer.LoadSignedJson(in_payload, self._hmac_key)
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155 | c103d7ae | Guido Trotter | answer = objects.ConfdReply.FromDict(dict_answer) |
156 | e4ccf6cd | Guido Trotter | return answer, salt
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157 | e4ccf6cd | Guido Trotter | |
158 | 96e03b0b | Guido Trotter | def ExpireRequests(self): |
159 | 96e03b0b | Guido Trotter | """Delete all the expired requests.
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160 | e4ccf6cd | Guido Trotter |
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161 | e4ccf6cd | Guido Trotter | """
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162 | e4ccf6cd | Guido Trotter | now = time.time() |
163 | 96e03b0b | Guido Trotter | while self._expire_requests: |
164 | 96e03b0b | Guido Trotter | expire_time, rsalt = self._expire_requests[0] |
165 | e4ccf6cd | Guido Trotter | if now >= expire_time:
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166 | 96e03b0b | Guido Trotter | self._expire_requests.pop(0) |
167 | 96e03b0b | Guido Trotter | (request, args) = self._requests[rsalt]
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168 | 96e03b0b | Guido Trotter | del self._requests[rsalt] |
169 | 96e03b0b | Guido Trotter | client_reply = ConfdUpcallPayload(salt=rsalt, |
170 | 96e03b0b | Guido Trotter | type=UPCALL_EXPIRE, |
171 | 96e03b0b | Guido Trotter | orig_request=request, |
172 | 5f6f260a | Guido Trotter | extra_args=args, |
173 | 5f6f260a | Guido Trotter | client=self,
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174 | 5f6f260a | Guido Trotter | ) |
175 | 96e03b0b | Guido Trotter | self._callback(client_reply)
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176 | e4ccf6cd | Guido Trotter | else:
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177 | e4ccf6cd | Guido Trotter | break
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178 | e4ccf6cd | Guido Trotter | |
179 | 96e03b0b | Guido Trotter | def SendRequest(self, request, args=None, coverage=None): |
180 | e4ccf6cd | Guido Trotter | """Send a confd request to some MCs
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181 | e4ccf6cd | Guido Trotter |
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182 | e4ccf6cd | Guido Trotter | @type request: L{objects.ConfdRequest}
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183 | e4ccf6cd | Guido Trotter | @param request: the request to send
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184 | e4ccf6cd | Guido Trotter | @type args: tuple
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185 | 90469357 | Guido Trotter | @keyword args: additional callback arguments
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186 | e4ccf6cd | Guido Trotter | @type coverage: integer
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187 | e4ccf6cd | Guido Trotter | @keyword coverage: number of remote nodes to contact
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188 | e4ccf6cd | Guido Trotter |
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189 | e4ccf6cd | Guido Trotter | """
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190 | e4ccf6cd | Guido Trotter | if coverage is None: |
191 | e4ccf6cd | Guido Trotter | coverage = min(len(self._peers), constants.CONFD_DEFAULT_REQ_COVERAGE) |
192 | e4ccf6cd | Guido Trotter | |
193 | e4ccf6cd | Guido Trotter | if coverage > len(self._peers): |
194 | e4ccf6cd | Guido Trotter | raise errors.ConfdClientError("Not enough MCs known to provide the" |
195 | e4ccf6cd | Guido Trotter | " desired coverage")
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196 | e4ccf6cd | Guido Trotter | |
197 | e4ccf6cd | Guido Trotter | if not request.rsalt: |
198 | e4ccf6cd | Guido Trotter | raise errors.ConfdClientError("Missing request rsalt") |
199 | e4ccf6cd | Guido Trotter | |
200 | 96e03b0b | Guido Trotter | self.ExpireRequests()
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201 | 96e03b0b | Guido Trotter | if request.rsalt in self._requests: |
202 | e4ccf6cd | Guido Trotter | raise errors.ConfdClientError("Duplicate request rsalt") |
203 | e4ccf6cd | Guido Trotter | |
204 | e4ccf6cd | Guido Trotter | if request.type not in constants.CONFD_REQS: |
205 | e4ccf6cd | Guido Trotter | raise errors.ConfdClientError("Invalid request type") |
206 | e4ccf6cd | Guido Trotter | |
207 | e4ccf6cd | Guido Trotter | random.shuffle(self._peers)
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208 | e4ccf6cd | Guido Trotter | targets = self._peers[:coverage]
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209 | e4ccf6cd | Guido Trotter | |
210 | e4ccf6cd | Guido Trotter | now = time.time() |
211 | e4ccf6cd | Guido Trotter | payload = self._PackRequest(request, now=now)
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212 | e4ccf6cd | Guido Trotter | |
213 | e4ccf6cd | Guido Trotter | for target in targets: |
214 | e4ccf6cd | Guido Trotter | try:
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215 | e4ccf6cd | Guido Trotter | self._socket.enqueue_send(target, self._confd_port, payload) |
216 | e4ccf6cd | Guido Trotter | except errors.UdpDataSizeError:
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217 | e4ccf6cd | Guido Trotter | raise errors.ConfdClientError("Request too big") |
218 | e4ccf6cd | Guido Trotter | |
219 | 96e03b0b | Guido Trotter | self._requests[request.rsalt] = (request, args)
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220 | e4ccf6cd | Guido Trotter | expire_time = now + constants.CONFD_CLIENT_EXPIRE_TIMEOUT |
221 | 96e03b0b | Guido Trotter | self._expire_requests.append((expire_time, request.rsalt))
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222 | e4ccf6cd | Guido Trotter | |
223 | e4ccf6cd | Guido Trotter | def HandleResponse(self, payload, ip, port): |
224 | e4ccf6cd | Guido Trotter | """Asynchronous handler for a confd reply
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225 | e4ccf6cd | Guido Trotter |
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226 | e4ccf6cd | Guido Trotter | Call the relevant callback associated to the current request.
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227 | e4ccf6cd | Guido Trotter |
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228 | e4ccf6cd | Guido Trotter | """
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229 | e4ccf6cd | Guido Trotter | try:
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230 | e4ccf6cd | Guido Trotter | try:
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231 | e4ccf6cd | Guido Trotter | answer, salt = self._UnpackReply(payload)
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232 | a3db74e4 | Guido Trotter | except (errors.SignatureError, errors.ConfdMagicError), err:
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233 | a3db74e4 | Guido Trotter | if self._logger: |
234 | a3db74e4 | Guido Trotter | self._logger.debug("Discarding broken package: %s" % err) |
235 | e4ccf6cd | Guido Trotter | return
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236 | e4ccf6cd | Guido Trotter | |
237 | e4ccf6cd | Guido Trotter | try:
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238 | 96e03b0b | Guido Trotter | (request, args) = self._requests[salt]
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239 | e4ccf6cd | Guido Trotter | except KeyError: |
240 | a3db74e4 | Guido Trotter | if self._logger: |
241 | a3db74e4 | Guido Trotter | self._logger.debug("Discarding unknown (expired?) reply: %s" % err) |
242 | 96e03b0b | Guido Trotter | return
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243 | 96e03b0b | Guido Trotter | |
244 | 96e03b0b | Guido Trotter | client_reply = ConfdUpcallPayload(salt=salt, |
245 | 96e03b0b | Guido Trotter | type=UPCALL_REPLY, |
246 | 96e03b0b | Guido Trotter | server_reply=answer, |
247 | 96e03b0b | Guido Trotter | orig_request=request, |
248 | 96e03b0b | Guido Trotter | server_ip=ip, |
249 | 96e03b0b | Guido Trotter | server_port=port, |
250 | 5f6f260a | Guido Trotter | extra_args=args, |
251 | 5f6f260a | Guido Trotter | client=self,
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252 | 5f6f260a | Guido Trotter | ) |
253 | 96e03b0b | Guido Trotter | self._callback(client_reply)
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254 | e4ccf6cd | Guido Trotter | |
255 | e4ccf6cd | Guido Trotter | finally:
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256 | 96e03b0b | Guido Trotter | self.ExpireRequests()
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257 | 96e03b0b | Guido Trotter | |
258 | 96e03b0b | Guido Trotter | |
259 | 96e03b0b | Guido Trotter | # UPCALL_REPLY: server reply upcall
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260 | 96e03b0b | Guido Trotter | # has all ConfdUpcallPayload fields populated
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261 | 96e03b0b | Guido Trotter | UPCALL_REPLY = 1
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262 | 96e03b0b | Guido Trotter | # UPCALL_EXPIRE: internal library request expire
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263 | 96e03b0b | Guido Trotter | # has only salt, type, orig_request and extra_args
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264 | 96e03b0b | Guido Trotter | UPCALL_EXPIRE = 2
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265 | 96e03b0b | Guido Trotter | CONFD_UPCALL_TYPES = frozenset([
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266 | 96e03b0b | Guido Trotter | UPCALL_REPLY, |
267 | 96e03b0b | Guido Trotter | UPCALL_EXPIRE, |
268 | 96e03b0b | Guido Trotter | ]) |
269 | 96e03b0b | Guido Trotter | |
270 | 96e03b0b | Guido Trotter | |
271 | 96e03b0b | Guido Trotter | class ConfdUpcallPayload(objects.ConfigObject): |
272 | 96e03b0b | Guido Trotter | """Callback argument for confd replies
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273 | 96e03b0b | Guido Trotter |
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274 | 96e03b0b | Guido Trotter | @type salt: string
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275 | 96e03b0b | Guido Trotter | @ivar salt: salt associated with the query
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276 | 96e03b0b | Guido Trotter | @type type: one of confd.client.CONFD_UPCALL_TYPES
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277 | 96e03b0b | Guido Trotter | @ivar type: upcall type (server reply, expired request, ...)
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278 | 96e03b0b | Guido Trotter | @type orig_request: L{objects.ConfdRequest}
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279 | 96e03b0b | Guido Trotter | @ivar orig_request: original request
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280 | 96e03b0b | Guido Trotter | @type server_reply: L{objects.ConfdReply}
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281 | 96e03b0b | Guido Trotter | @ivar server_reply: server reply
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282 | 96e03b0b | Guido Trotter | @type server_ip: string
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283 | 96e03b0b | Guido Trotter | @ivar server_ip: answering server ip address
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284 | 96e03b0b | Guido Trotter | @type server_port: int
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285 | 96e03b0b | Guido Trotter | @ivar server_port: answering server port
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286 | 96e03b0b | Guido Trotter | @type extra_args: any
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287 | 96e03b0b | Guido Trotter | @ivar extra_args: 'args' argument of the SendRequest function
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288 | 5f6f260a | Guido Trotter | @type client: L{ConfdClient}
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289 | 5f6f260a | Guido Trotter | @ivar client: current confd client instance
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290 | 96e03b0b | Guido Trotter |
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291 | 96e03b0b | Guido Trotter | """
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292 | 96e03b0b | Guido Trotter | __slots__ = [ |
293 | 96e03b0b | Guido Trotter | "salt",
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294 | 96e03b0b | Guido Trotter | "type",
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295 | 96e03b0b | Guido Trotter | "orig_request",
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296 | 96e03b0b | Guido Trotter | "server_reply",
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297 | 96e03b0b | Guido Trotter | "server_ip",
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298 | 96e03b0b | Guido Trotter | "server_port",
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299 | 96e03b0b | Guido Trotter | "extra_args",
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300 | 5f6f260a | Guido Trotter | "client",
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301 | 96e03b0b | Guido Trotter | ] |
302 | e4ccf6cd | Guido Trotter | |
303 | e4ccf6cd | Guido Trotter | |
304 | e4ccf6cd | Guido Trotter | class ConfdClientRequest(objects.ConfdRequest): |
305 | e4ccf6cd | Guido Trotter | """This is the client-side version of ConfdRequest.
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306 | e4ccf6cd | Guido Trotter |
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307 | e4ccf6cd | Guido Trotter | This version of the class helps creating requests, on the client side, by
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308 | e4ccf6cd | Guido Trotter | filling in some default values.
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309 | e4ccf6cd | Guido Trotter |
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310 | e4ccf6cd | Guido Trotter | """
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311 | e4ccf6cd | Guido Trotter | def __init__(self, **kwargs): |
312 | e4ccf6cd | Guido Trotter | objects.ConfdRequest.__init__(self, **kwargs)
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313 | e4ccf6cd | Guido Trotter | if not self.rsalt: |
314 | e4ccf6cd | Guido Trotter | self.rsalt = utils.NewUUID()
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315 | e4ccf6cd | Guido Trotter | if not self.protocol: |
316 | e4ccf6cd | Guido Trotter | self.protocol = constants.CONFD_PROTOCOL_VERSION
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317 | e4ccf6cd | Guido Trotter | if self.type not in constants.CONFD_REQS: |
318 | e4ccf6cd | Guido Trotter | raise errors.ConfdClientError("Invalid request type") |
319 | e4ccf6cd | Guido Trotter | |
320 | 392ca296 | Guido Trotter | |
321 | 392ca296 | Guido Trotter | class ConfdFilterCallback: |
322 | 392ca296 | Guido Trotter | """Callback that calls another callback, but filters duplicate results.
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323 | 392ca296 | Guido Trotter |
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324 | 392ca296 | Guido Trotter | """
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325 | 392ca296 | Guido Trotter | def __init__(self, callback, logger=None): |
326 | 392ca296 | Guido Trotter | """Constructor for ConfdFilterCallback
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327 | 392ca296 | Guido Trotter |
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328 | 392ca296 | Guido Trotter | @type callback: f(L{ConfdUpcallPayload})
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329 | 392ca296 | Guido Trotter | @param callback: function to call when getting answers
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330 | 69b99987 | Michael Hanselmann | @type logger: logging.Logger
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331 | 392ca296 | Guido Trotter | @keyword logger: optional logger for internal conditions
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332 | 392ca296 | Guido Trotter |
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333 | 392ca296 | Guido Trotter | """
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334 | 392ca296 | Guido Trotter | if not callable(callback): |
335 | 392ca296 | Guido Trotter | raise errors.ProgrammerError("callback must be callable") |
336 | 392ca296 | Guido Trotter | |
337 | 392ca296 | Guido Trotter | self._callback = callback
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338 | 392ca296 | Guido Trotter | self._logger = logger
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339 | 392ca296 | Guido Trotter | # answers contains a dict of salt -> answer
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340 | 392ca296 | Guido Trotter | self._answers = {}
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341 | 392ca296 | Guido Trotter | |
342 | 392ca296 | Guido Trotter | def _LogFilter(self, salt, new_reply, old_reply): |
343 | 392ca296 | Guido Trotter | if not self._logger: |
344 | 392ca296 | Guido Trotter | return
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345 | 392ca296 | Guido Trotter | |
346 | 392ca296 | Guido Trotter | if new_reply.serial > old_reply.serial:
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347 | 392ca296 | Guido Trotter | self._logger.debug("Filtering confirming answer, with newer" |
348 | 392ca296 | Guido Trotter | " serial for query %s" % salt)
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349 | 392ca296 | Guido Trotter | elif new_reply.serial == old_reply.serial:
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350 | 392ca296 | Guido Trotter | if new_reply.answer != old_reply.answer:
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351 | 392ca296 | Guido Trotter | self._logger.warning("Got incoherent answers for query %s" |
352 | 392ca296 | Guido Trotter | " (serial: %s)" % (salt, new_reply.serial))
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353 | 392ca296 | Guido Trotter | else:
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354 | 392ca296 | Guido Trotter | self._logger.debug("Filtering confirming answer, with same" |
355 | 392ca296 | Guido Trotter | " serial for query %s" % salt)
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356 | 392ca296 | Guido Trotter | else:
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357 | 392ca296 | Guido Trotter | self._logger.debug("Filtering outdated answer for query %s" |
358 | 392ca296 | Guido Trotter | " serial: (%d < %d)" % (salt, old_reply.serial,
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359 | 392ca296 | Guido Trotter | new_reply.serial)) |
360 | 392ca296 | Guido Trotter | |
361 | 392ca296 | Guido Trotter | def _HandleExpire(self, up): |
362 | 392ca296 | Guido Trotter | # if we have no answer we have received none, before the expiration.
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363 | a9613def | Guido Trotter | if up.salt in self._answers: |
364 | a9613def | Guido Trotter | del self._answers[up.salt] |
365 | 392ca296 | Guido Trotter | |
366 | 392ca296 | Guido Trotter | def _HandleReply(self, up): |
367 | 392ca296 | Guido Trotter | """Handle a single confd reply, and decide whether to filter it.
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368 | 392ca296 | Guido Trotter |
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369 | 392ca296 | Guido Trotter | @rtype: boolean
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370 | 392ca296 | Guido Trotter | @return: True if the reply should be filtered, False if it should be passed
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371 | 392ca296 | Guido Trotter | on to the up-callback
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372 | 392ca296 | Guido Trotter |
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373 | 392ca296 | Guido Trotter | """
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374 | 392ca296 | Guido Trotter | filter_upcall = False
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375 | 392ca296 | Guido Trotter | salt = up.salt |
376 | 392ca296 | Guido Trotter | if salt not in self._answers: |
377 | 392ca296 | Guido Trotter | # first answer for a query (don't filter, and record)
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378 | 392ca296 | Guido Trotter | self._answers[salt] = up.server_reply
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379 | 392ca296 | Guido Trotter | elif up.server_reply.serial > self._answers[salt].serial: |
380 | 392ca296 | Guido Trotter | # newer answer (record, and compare contents)
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381 | 392ca296 | Guido Trotter | old_answer = self._answers[salt]
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382 | 392ca296 | Guido Trotter | self._answers[salt] = up.server_reply
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383 | 392ca296 | Guido Trotter | if up.server_reply.answer == old_answer.answer:
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384 | 392ca296 | Guido Trotter | # same content (filter) (version upgrade was unrelated)
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385 | 392ca296 | Guido Trotter | filter_upcall = True
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386 | 392ca296 | Guido Trotter | self._LogFilter(salt, up.server_reply, old_answer)
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387 | 392ca296 | Guido Trotter | # else: different content, pass up a second answer
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388 | 392ca296 | Guido Trotter | else:
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389 | 392ca296 | Guido Trotter | # older or same-version answer (duplicate or outdated, filter)
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390 | 392ca296 | Guido Trotter | filter_upcall = True
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391 | 392ca296 | Guido Trotter | self._LogFilter(salt, up.server_reply, self._answers[salt]) |
392 | 392ca296 | Guido Trotter | |
393 | 392ca296 | Guido Trotter | return filter_upcall
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394 | 392ca296 | Guido Trotter | |
395 | 392ca296 | Guido Trotter | def __call__(self, up): |
396 | 392ca296 | Guido Trotter | """Filtering callback
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397 | 392ca296 | Guido Trotter |
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398 | 392ca296 | Guido Trotter | @type up: L{ConfdUpcallPayload}
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399 | 392ca296 | Guido Trotter | @param up: upper callback
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400 | 392ca296 | Guido Trotter |
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401 | 392ca296 | Guido Trotter | """
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402 | 392ca296 | Guido Trotter | filter_upcall = False
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403 | 392ca296 | Guido Trotter | if up.type == UPCALL_REPLY:
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404 | 392ca296 | Guido Trotter | filter_upcall = self._HandleReply(up)
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405 | 392ca296 | Guido Trotter | elif up.type == UPCALL_EXPIRE:
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406 | 392ca296 | Guido Trotter | self._HandleExpire(up)
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407 | 392ca296 | Guido Trotter | |
408 | 392ca296 | Guido Trotter | if not filter_upcall: |
409 | 392ca296 | Guido Trotter | self._callback(up) |