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1 | 821d9e43 | Michael Hanselmann | #
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2 | 821d9e43 | Michael Hanselmann | #
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3 | 821d9e43 | Michael Hanselmann | |
4 | 821d9e43 | Michael Hanselmann | # Copyright (C) 2006, 2007, 2008 Google Inc.
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5 | 821d9e43 | Michael Hanselmann | #
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6 | 821d9e43 | Michael Hanselmann | # This program is free software; you can redistribute it and/or modify
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7 | 821d9e43 | Michael Hanselmann | # it under the terms of the GNU General Public License as published by
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8 | 821d9e43 | Michael Hanselmann | # the Free Software Foundation; either version 2 of the License, or
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9 | 821d9e43 | Michael Hanselmann | # (at your option) any later version.
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10 | 821d9e43 | Michael Hanselmann | #
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11 | 821d9e43 | Michael Hanselmann | # This program is distributed in the hope that it will be useful, but
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12 | 821d9e43 | Michael Hanselmann | # WITHOUT ANY WARRANTY; without even the implied warranty of
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13 | 821d9e43 | Michael Hanselmann | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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14 | 821d9e43 | Michael Hanselmann | # General Public License for more details.
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15 | 821d9e43 | Michael Hanselmann | #
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16 | 821d9e43 | Michael Hanselmann | # You should have received a copy of the GNU General Public License
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17 | 821d9e43 | Michael Hanselmann | # along with this program; if not, write to the Free Software
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18 | 821d9e43 | Michael Hanselmann | # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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19 | 821d9e43 | Michael Hanselmann | # 02110-1301, USA.
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20 | 821d9e43 | Michael Hanselmann | |
21 | 821d9e43 | Michael Hanselmann | |
22 | 821d9e43 | Michael Hanselmann | """Module with helper classes and functions for daemons"""
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23 | 821d9e43 | Michael Hanselmann | |
24 | 821d9e43 | Michael Hanselmann | |
25 | 112d240d | Guido Trotter | import asyncore |
26 | 3b1b0cb6 | Guido Trotter | import os |
27 | 821d9e43 | Michael Hanselmann | import signal |
28 | 821d9e43 | Michael Hanselmann | import errno |
29 | 04ccf5e9 | Guido Trotter | import logging |
30 | a02b89cf | Guido Trotter | import sched |
31 | a02b89cf | Guido Trotter | import time |
32 | 5f3269fc | Guido Trotter | import socket |
33 | c124045f | Iustin Pop | import sys |
34 | 821d9e43 | Michael Hanselmann | |
35 | 821d9e43 | Michael Hanselmann | from ganeti import utils |
36 | 04ccf5e9 | Guido Trotter | from ganeti import constants |
37 | a02b89cf | Guido Trotter | from ganeti import errors |
38 | a02b89cf | Guido Trotter | |
39 | a02b89cf | Guido Trotter | |
40 | a02b89cf | Guido Trotter | class SchedulerBreakout(Exception): |
41 | a02b89cf | Guido Trotter | """Exception used to get out of the scheduler loop
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42 | a02b89cf | Guido Trotter |
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43 | a02b89cf | Guido Trotter | """
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44 | a02b89cf | Guido Trotter | |
45 | a02b89cf | Guido Trotter | |
46 | a02b89cf | Guido Trotter | def AsyncoreDelayFunction(timeout): |
47 | a02b89cf | Guido Trotter | """Asyncore-compatible scheduler delay function.
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48 | a02b89cf | Guido Trotter |
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49 | a02b89cf | Guido Trotter | This is a delay function for sched that, rather than actually sleeping,
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50 | a02b89cf | Guido Trotter | executes asyncore events happening in the meantime.
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51 | a02b89cf | Guido Trotter |
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52 | a02b89cf | Guido Trotter | After an event has occurred, rather than returning, it raises a
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53 | a02b89cf | Guido Trotter | SchedulerBreakout exception, which will force the current scheduler.run()
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54 | a02b89cf | Guido Trotter | invocation to terminate, so that we can also check for signals. The main loop
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55 | a02b89cf | Guido Trotter | will then call the scheduler run again, which will allow it to actually
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56 | a02b89cf | Guido Trotter | process any due events.
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57 | a02b89cf | Guido Trotter |
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58 | a02b89cf | Guido Trotter | This is needed because scheduler.run() doesn't support a count=..., as
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59 | a02b89cf | Guido Trotter | asyncore loop, and the scheduler module documents throwing exceptions from
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60 | a02b89cf | Guido Trotter | inside the delay function as an allowed usage model.
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61 | a02b89cf | Guido Trotter |
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62 | a02b89cf | Guido Trotter | """
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63 | a02b89cf | Guido Trotter | asyncore.loop(timeout=timeout, count=1, use_poll=True) |
64 | a02b89cf | Guido Trotter | raise SchedulerBreakout()
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65 | a02b89cf | Guido Trotter | |
66 | a02b89cf | Guido Trotter | |
67 | a02b89cf | Guido Trotter | class AsyncoreScheduler(sched.scheduler): |
68 | a02b89cf | Guido Trotter | """Event scheduler integrated with asyncore
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69 | a02b89cf | Guido Trotter |
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70 | a02b89cf | Guido Trotter | """
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71 | a02b89cf | Guido Trotter | def __init__(self, timefunc): |
72 | a02b89cf | Guido Trotter | sched.scheduler.__init__(self, timefunc, AsyncoreDelayFunction)
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73 | 821d9e43 | Michael Hanselmann | |
74 | 821d9e43 | Michael Hanselmann | |
75 | 5f3269fc | Guido Trotter | class AsyncUDPSocket(asyncore.dispatcher): |
76 | 5f3269fc | Guido Trotter | """An improved asyncore udp socket.
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77 | 5f3269fc | Guido Trotter |
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78 | 5f3269fc | Guido Trotter | """
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79 | 5f3269fc | Guido Trotter | def __init__(self): |
80 | 5f3269fc | Guido Trotter | """Constructor for AsyncUDPSocket
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81 | 5f3269fc | Guido Trotter |
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82 | 5f3269fc | Guido Trotter | """
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83 | 5f3269fc | Guido Trotter | asyncore.dispatcher.__init__(self)
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84 | 5f3269fc | Guido Trotter | self._out_queue = []
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85 | 5f3269fc | Guido Trotter | self.create_socket(socket.AF_INET, socket.SOCK_DGRAM)
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86 | 5f3269fc | Guido Trotter | |
87 | 5f3269fc | Guido Trotter | # this method is overriding an asyncore.dispatcher method
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88 | 5f3269fc | Guido Trotter | def handle_connect(self): |
89 | 5f3269fc | Guido Trotter | # Python thinks that the first udp message from a source qualifies as a
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90 | 5f3269fc | Guido Trotter | # "connect" and further ones are part of the same connection. We beg to
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91 | 5f3269fc | Guido Trotter | # differ and treat all messages equally.
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92 | 5f3269fc | Guido Trotter | pass
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93 | 5f3269fc | Guido Trotter | |
94 | 5f3269fc | Guido Trotter | # this method is overriding an asyncore.dispatcher method
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95 | 5f3269fc | Guido Trotter | def handle_read(self): |
96 | 5f3269fc | Guido Trotter | try:
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97 | 5f3269fc | Guido Trotter | try:
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98 | c8eded0b | Guido Trotter | payload, address = self.recvfrom(constants.MAX_UDP_DATA_SIZE)
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99 | 5f3269fc | Guido Trotter | except socket.error, err:
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100 | 5f3269fc | Guido Trotter | if err.errno == errno.EINTR:
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101 | 5f3269fc | Guido Trotter | # we got a signal while trying to read. no need to do anything,
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102 | 5f3269fc | Guido Trotter | # handle_read will be called again if there is data on the socket.
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103 | 5f3269fc | Guido Trotter | return
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104 | 5f3269fc | Guido Trotter | else:
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105 | 5f3269fc | Guido Trotter | raise
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106 | 5f3269fc | Guido Trotter | ip, port = address |
107 | 5f3269fc | Guido Trotter | self.handle_datagram(payload, ip, port)
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108 | 7260cfbe | Iustin Pop | except: # pylint: disable-msg=W0702 |
109 | 5f3269fc | Guido Trotter | # we need to catch any exception here, log it, but proceed, because even
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110 | 5f3269fc | Guido Trotter | # if we failed handling a single request, we still want to continue.
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111 | 5f3269fc | Guido Trotter | logging.error("Unexpected exception", exc_info=True) |
112 | 5f3269fc | Guido Trotter | |
113 | 5f3269fc | Guido Trotter | def handle_datagram(self, payload, ip, port): |
114 | 5f3269fc | Guido Trotter | """Handle an already read udp datagram
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115 | 5f3269fc | Guido Trotter |
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116 | 5f3269fc | Guido Trotter | """
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117 | 5f3269fc | Guido Trotter | raise NotImplementedError |
118 | 5f3269fc | Guido Trotter | |
119 | 5f3269fc | Guido Trotter | # this method is overriding an asyncore.dispatcher method
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120 | 5f3269fc | Guido Trotter | def writable(self): |
121 | 5f3269fc | Guido Trotter | # We should check whether we can write to the socket only if we have
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122 | 5f3269fc | Guido Trotter | # something scheduled to be written
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123 | 5f3269fc | Guido Trotter | return bool(self._out_queue) |
124 | 5f3269fc | Guido Trotter | |
125 | 5f3269fc | Guido Trotter | def handle_write(self): |
126 | 5f3269fc | Guido Trotter | try:
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127 | 5f3269fc | Guido Trotter | if not self._out_queue: |
128 | 5f3269fc | Guido Trotter | logging.error("handle_write called with empty output queue")
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129 | 5f3269fc | Guido Trotter | return
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130 | 5f3269fc | Guido Trotter | (ip, port, payload) = self._out_queue[0] |
131 | 5f3269fc | Guido Trotter | try:
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132 | 5f3269fc | Guido Trotter | self.sendto(payload, 0, (ip, port)) |
133 | 5f3269fc | Guido Trotter | except socket.error, err:
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134 | 5f3269fc | Guido Trotter | if err.errno == errno.EINTR:
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135 | 5f3269fc | Guido Trotter | # we got a signal while trying to write. no need to do anything,
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136 | 5f3269fc | Guido Trotter | # handle_write will be called again because we haven't emptied the
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137 | 5f3269fc | Guido Trotter | # _out_queue, and we'll try again
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138 | 5f3269fc | Guido Trotter | return
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139 | 5f3269fc | Guido Trotter | else:
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140 | 5f3269fc | Guido Trotter | raise
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141 | 5f3269fc | Guido Trotter | self._out_queue.pop(0) |
142 | 7260cfbe | Iustin Pop | except: # pylint: disable-msg=W0702 |
143 | 5f3269fc | Guido Trotter | # we need to catch any exception here, log it, but proceed, because even
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144 | 5f3269fc | Guido Trotter | # if we failed sending a single datagram we still want to continue.
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145 | 5f3269fc | Guido Trotter | logging.error("Unexpected exception", exc_info=True) |
146 | 5f3269fc | Guido Trotter | |
147 | 5f3269fc | Guido Trotter | def enqueue_send(self, ip, port, payload): |
148 | 5f3269fc | Guido Trotter | """Enqueue a datagram to be sent when possible
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149 | 5f3269fc | Guido Trotter |
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150 | 5f3269fc | Guido Trotter | """
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151 | c8eded0b | Guido Trotter | if len(payload) > constants.MAX_UDP_DATA_SIZE: |
152 | c8eded0b | Guido Trotter | raise errors.UdpDataSizeError('Packet too big: %s > %s' % (len(payload), |
153 | c8eded0b | Guido Trotter | constants.MAX_UDP_DATA_SIZE)) |
154 | 5f3269fc | Guido Trotter | self._out_queue.append((ip, port, payload))
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155 | 5f3269fc | Guido Trotter | |
156 | 5f3269fc | Guido Trotter | |
157 | 821d9e43 | Michael Hanselmann | class Mainloop(object): |
158 | 821d9e43 | Michael Hanselmann | """Generic mainloop for daemons
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159 | 821d9e43 | Michael Hanselmann |
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160 | 69b99987 | Michael Hanselmann | @ivar scheduler: A sched.scheduler object, which can be used to register
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161 | 69b99987 | Michael Hanselmann | timed events
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162 | 69b99987 | Michael Hanselmann |
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163 | 821d9e43 | Michael Hanselmann | """
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164 | 821d9e43 | Michael Hanselmann | def __init__(self): |
165 | b14b975f | Michael Hanselmann | """Constructs a new Mainloop instance.
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166 | b14b975f | Michael Hanselmann |
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167 | b14b975f | Michael Hanselmann | """
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168 | 821d9e43 | Michael Hanselmann | self._signal_wait = []
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169 | a02b89cf | Guido Trotter | self.scheduler = AsyncoreScheduler(time.time)
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170 | 821d9e43 | Michael Hanselmann | |
171 | 9b739173 | Guido Trotter | @utils.SignalHandled([signal.SIGCHLD])
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172 | 9b739173 | Guido Trotter | @utils.SignalHandled([signal.SIGTERM])
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173 | 69b99987 | Michael Hanselmann | def Run(self, signal_handlers=None): |
174 | b14b975f | Michael Hanselmann | """Runs the mainloop.
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175 | b14b975f | Michael Hanselmann |
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176 | 9b739173 | Guido Trotter | @type signal_handlers: dict
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177 | 9b739173 | Guido Trotter | @param signal_handlers: signal->L{utils.SignalHandler} passed by decorator
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178 | b14b975f | Michael Hanselmann |
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179 | b14b975f | Michael Hanselmann | """
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180 | 9b739173 | Guido Trotter | assert isinstance(signal_handlers, dict) and \ |
181 | 9b739173 | Guido Trotter | len(signal_handlers) > 0, \ |
182 | 9b739173 | Guido Trotter | "Broken SignalHandled decorator"
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183 | 9b739173 | Guido Trotter | running = True
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184 | 9b739173 | Guido Trotter | # Start actual main loop
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185 | 9b739173 | Guido Trotter | while running:
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186 | a02b89cf | Guido Trotter | if not self.scheduler.empty(): |
187 | a02b89cf | Guido Trotter | try:
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188 | a02b89cf | Guido Trotter | self.scheduler.run()
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189 | a02b89cf | Guido Trotter | except SchedulerBreakout:
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190 | a02b89cf | Guido Trotter | pass
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191 | a02b89cf | Guido Trotter | else:
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192 | a02b89cf | Guido Trotter | asyncore.loop(count=1, use_poll=True) |
193 | 9b739173 | Guido Trotter | |
194 | 9b739173 | Guido Trotter | # Check whether a signal was raised
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195 | 9b739173 | Guido Trotter | for sig in signal_handlers: |
196 | 9b739173 | Guido Trotter | handler = signal_handlers[sig] |
197 | 9b739173 | Guido Trotter | if handler.called:
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198 | 9b739173 | Guido Trotter | self._CallSignalWaiters(sig)
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199 | 9b739173 | Guido Trotter | running = (sig != signal.SIGTERM) |
200 | 9b739173 | Guido Trotter | handler.Clear() |
201 | a570e2a8 | Guido Trotter | |
202 | b14b975f | Michael Hanselmann | def _CallSignalWaiters(self, signum): |
203 | b14b975f | Michael Hanselmann | """Calls all signal waiters for a certain signal.
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204 | b14b975f | Michael Hanselmann |
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205 | b14b975f | Michael Hanselmann | @type signum: int
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206 | b14b975f | Michael Hanselmann | @param signum: Signal number
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207 | b14b975f | Michael Hanselmann |
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208 | b14b975f | Michael Hanselmann | """
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209 | b14b975f | Michael Hanselmann | for owner in self._signal_wait: |
210 | a9fe7232 | Guido Trotter | owner.OnSignal(signum) |
211 | 821d9e43 | Michael Hanselmann | |
212 | 821d9e43 | Michael Hanselmann | def RegisterSignal(self, owner): |
213 | 821d9e43 | Michael Hanselmann | """Registers a receiver for signal notifications
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214 | 821d9e43 | Michael Hanselmann |
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215 | 821d9e43 | Michael Hanselmann | The receiver must support a "OnSignal(self, signum)" function.
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216 | 821d9e43 | Michael Hanselmann |
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217 | 821d9e43 | Michael Hanselmann | @type owner: instance
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218 | 821d9e43 | Michael Hanselmann | @param owner: Receiver
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219 | 821d9e43 | Michael Hanselmann |
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220 | 821d9e43 | Michael Hanselmann | """
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221 | 821d9e43 | Michael Hanselmann | self._signal_wait.append(owner)
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222 | b11c9e5c | Michael Hanselmann | |
223 | 04ccf5e9 | Guido Trotter | |
224 | 04ccf5e9 | Guido Trotter | def GenericMain(daemon_name, optionparser, dirs, check_fn, exec_fn): |
225 | 04ccf5e9 | Guido Trotter | """Shared main function for daemons.
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226 | 04ccf5e9 | Guido Trotter |
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227 | 04ccf5e9 | Guido Trotter | @type daemon_name: string
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228 | 04ccf5e9 | Guido Trotter | @param daemon_name: daemon name
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229 | 69b99987 | Michael Hanselmann | @type optionparser: optparse.OptionParser
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230 | 04ccf5e9 | Guido Trotter | @param optionparser: initialized optionparser with daemon-specific options
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231 | 04ccf5e9 | Guido Trotter | (common -f -d options will be handled by this module)
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232 | 04ccf5e9 | Guido Trotter | @type dirs: list of strings
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233 | 04ccf5e9 | Guido Trotter | @param dirs: list of directories that must exist for this daemon to work
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234 | 04ccf5e9 | Guido Trotter | @type check_fn: function which accepts (options, args)
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235 | 04ccf5e9 | Guido Trotter | @param check_fn: function that checks start conditions and exits if they're
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236 | 04ccf5e9 | Guido Trotter | not met
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237 | 04ccf5e9 | Guido Trotter | @type exec_fn: function which accepts (options, args)
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238 | 04ccf5e9 | Guido Trotter | @param exec_fn: function that's executed with the daemon's pid file held, and
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239 | 04ccf5e9 | Guido Trotter | runs the daemon itself.
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240 | 04ccf5e9 | Guido Trotter |
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241 | 04ccf5e9 | Guido Trotter | """
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242 | 04ccf5e9 | Guido Trotter | optionparser.add_option("-f", "--foreground", dest="fork", |
243 | 04ccf5e9 | Guido Trotter | help="Don't detach from the current terminal",
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244 | 04ccf5e9 | Guido Trotter | default=True, action="store_false") |
245 | 04ccf5e9 | Guido Trotter | optionparser.add_option("-d", "--debug", dest="debug", |
246 | 04ccf5e9 | Guido Trotter | help="Enable some debug messages",
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247 | 04ccf5e9 | Guido Trotter | default=False, action="store_true") |
248 | 04ccf5e9 | Guido Trotter | if daemon_name in constants.DAEMONS_PORTS: |
249 | 04ccf5e9 | Guido Trotter | # for networked daemons we also allow choosing the bind port and address.
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250 | 04ccf5e9 | Guido Trotter | # by default we use the port provided by utils.GetDaemonPort, and bind to
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251 | 04ccf5e9 | Guido Trotter | # 0.0.0.0 (which is represented by and empty bind address.
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252 | 04ccf5e9 | Guido Trotter | port = utils.GetDaemonPort(daemon_name) |
253 | 04ccf5e9 | Guido Trotter | optionparser.add_option("-p", "--port", dest="port", |
254 | 04ccf5e9 | Guido Trotter | help="Network port (%s default)." % port,
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255 | 04ccf5e9 | Guido Trotter | default=port, type="int")
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256 | 04ccf5e9 | Guido Trotter | optionparser.add_option("-b", "--bind", dest="bind_address", |
257 | 04ccf5e9 | Guido Trotter | help="Bind address",
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258 | 04ccf5e9 | Guido Trotter | default="", metavar="ADDRESS") |
259 | 04ccf5e9 | Guido Trotter | |
260 | 3b1b0cb6 | Guido Trotter | if daemon_name in constants.DAEMONS_SSL: |
261 | 3b1b0cb6 | Guido Trotter | default_cert, default_key = constants.DAEMONS_SSL[daemon_name] |
262 | 3b1b0cb6 | Guido Trotter | optionparser.add_option("--no-ssl", dest="ssl", |
263 | 3b1b0cb6 | Guido Trotter | help="Do not secure HTTP protocol with SSL",
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264 | 3b1b0cb6 | Guido Trotter | default=True, action="store_false") |
265 | 3b1b0cb6 | Guido Trotter | optionparser.add_option("-K", "--ssl-key", dest="ssl_key", |
266 | 3b1b0cb6 | Guido Trotter | help="SSL key",
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267 | 3b1b0cb6 | Guido Trotter | default=default_key, type="string")
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268 | 3b1b0cb6 | Guido Trotter | optionparser.add_option("-C", "--ssl-cert", dest="ssl_cert", |
269 | 3b1b0cb6 | Guido Trotter | help="SSL certificate",
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270 | 3b1b0cb6 | Guido Trotter | default=default_cert, type="string")
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271 | 3b1b0cb6 | Guido Trotter | |
272 | 04ccf5e9 | Guido Trotter | multithread = utils.no_fork = daemon_name in constants.MULTITHREADED_DAEMONS
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273 | 04ccf5e9 | Guido Trotter | |
274 | 04ccf5e9 | Guido Trotter | options, args = optionparser.parse_args() |
275 | 04ccf5e9 | Guido Trotter | |
276 | 3b1b0cb6 | Guido Trotter | if hasattr(options, 'ssl') and options.ssl: |
277 | 3b1b0cb6 | Guido Trotter | if not (options.ssl_cert and options.ssl_key): |
278 | 3b1b0cb6 | Guido Trotter | print >> sys.stderr, "Need key and certificate to use ssl" |
279 | 3b1b0cb6 | Guido Trotter | sys.exit(constants.EXIT_FAILURE) |
280 | 3b1b0cb6 | Guido Trotter | for fname in (options.ssl_cert, options.ssl_key): |
281 | 3b1b0cb6 | Guido Trotter | if not os.path.isfile(fname): |
282 | 3b1b0cb6 | Guido Trotter | print >> sys.stderr, "Need ssl file %s to run" % fname |
283 | 3b1b0cb6 | Guido Trotter | sys.exit(constants.EXIT_FAILURE) |
284 | 3b1b0cb6 | Guido Trotter | |
285 | 3b1b0cb6 | Guido Trotter | if check_fn is not None: |
286 | 3b1b0cb6 | Guido Trotter | check_fn(options, args) |
287 | 3b1b0cb6 | Guido Trotter | |
288 | 04ccf5e9 | Guido Trotter | utils.EnsureDirs(dirs) |
289 | 04ccf5e9 | Guido Trotter | |
290 | 04ccf5e9 | Guido Trotter | if options.fork:
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291 | 04ccf5e9 | Guido Trotter | utils.CloseFDs() |
292 | 04ccf5e9 | Guido Trotter | utils.Daemonize(logfile=constants.DAEMONS_LOGFILES[daemon_name]) |
293 | 04ccf5e9 | Guido Trotter | |
294 | 04ccf5e9 | Guido Trotter | utils.WritePidFile(daemon_name) |
295 | 04ccf5e9 | Guido Trotter | try:
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296 | 04ccf5e9 | Guido Trotter | utils.SetupLogging(logfile=constants.DAEMONS_LOGFILES[daemon_name], |
297 | 04ccf5e9 | Guido Trotter | debug=options.debug, |
298 | 04ccf5e9 | Guido Trotter | stderr_logging=not options.fork,
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299 | 04ccf5e9 | Guido Trotter | multithreaded=multithread) |
300 | 099c52ad | Iustin Pop | logging.info("%s daemon startup", daemon_name)
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301 | 04ccf5e9 | Guido Trotter | exec_fn(options, args) |
302 | 04ccf5e9 | Guido Trotter | finally:
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303 | 04ccf5e9 | Guido Trotter | utils.RemovePidFile(daemon_name) |