Revision b11c9e5c lib/daemon.py
| b/lib/daemon.py | ||
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import select |
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import signal |
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import errno |
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import time |
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from ganeti import utils |
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class Timer(object): |
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def __init__(self, owner, timer_id, start, interval, repeat): |
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self.owner = owner |
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self.timer_id = timer_id |
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self.start = start |
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self.interval = interval |
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self.repeat = repeat |
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class Mainloop(object): |
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"""Generic mainloop for daemons |
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|
| ... | ... | |
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self._io_wait_add = [] |
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self._io_wait_remove = [] |
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self._signal_wait = [] |
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self._timer_id_last = 0 |
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self._timer = {}
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self._timer_add = [] |
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self._timer_remove = [] |
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def Run(self, handle_sigchld=True, handle_sigterm=True, stop_on_empty=False): |
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"""Runs the mainloop. |
| ... | ... | |
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try: |
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running = True |
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timeout = None |
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timeout_needs_update = True |
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# Start actual main loop |
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while running: |
| ... | ... | |
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poller.register(fd, conditions) |
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self._io_wait_add = [] |
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# Add new timers |
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if self._timer_add: |
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timeout_needs_update = True |
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for timer in self._timer_add: |
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self._timer[timer.timer_id] = timer |
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del self._timer_add[:] |
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# Remove timers |
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if self._timer_remove: |
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timeout_needs_update = True |
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for timer_id in self._timer_remove: |
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try: |
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del self._timer[timer_id] |
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except KeyError: |
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pass |
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del self._timer_remove[:] |
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# Stop if nothing is listening anymore |
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if stop_on_empty and not self._io_wait:
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if stop_on_empty and not (self._io_wait or self._timer):
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break |
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# Calculate timeout again if required |
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if timeout_needs_update: |
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timeout = self._CalcTimeout(time.time()) |
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# Wait for I/O events |
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try: |
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io_events = poller.poll() |
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io_events = poller.poll(timeout)
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except select.error, err: |
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# EINTR can happen when signals are sent |
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if err.args and err.args[0] in (errno.EINTR,): |
| ... | ... | |
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else: |
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raise |
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after_poll = time.time() |
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if io_events: |
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# Check for I/O events |
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for (evfd, evcond) in io_events: |
| ... | ... | |
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if owner: |
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owner.OnIO(evfd, evcond) |
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if self._timer: |
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self._CheckTimers(after_poll) |
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# Check whether signal was raised |
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if sigchld_handler and sigchld_handler.called: |
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self._CallSignalWaiters(signal.SIGCHLD) |
| ... | ... | |
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if sigchld_handler: |
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sigchld_handler.Reset() |
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def _CalcTimeout(self, now): |
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if not self._timer: |
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return None |
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timeout = None |
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# TODO: Repeating timers |
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min_timeout = 0.001 |
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for timer in self._timer.itervalues(): |
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time_left = (timer.start + timer.interval) - now |
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if timeout is None or time_left < timeout: |
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timeout = time_left |
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if timeout < 0: |
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timeout = 0 |
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break |
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elif timeout < min_timeout: |
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timeout = min_timeout |
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break |
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return timeout * 1000.0 |
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def _CheckTimers(self, now): |
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# TODO: Repeating timers |
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for timer in self._timer.itervalues(): |
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if now < (timer.start + timer.interval): |
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continue |
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timer.owner.OnTimer(timer.timer_id) |
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# TODO: Repeating timers should not be removed |
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self._timer_remove.append(timer.timer_id) |
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def _CallSignalWaiters(self, signum): |
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"""Calls all signal waiters for a certain signal. |
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|
| ... | ... | |
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""" |
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self._signal_wait.append(owner) |
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def AddTimer(self, owner, interval, repeat): |
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"""Add a new timer. |
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The receiver must support a "OnTimer(self, timer_id)" function. |
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@type owner: instance |
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@param owner: Receiver |
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@type interval: int or float |
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@param interval: Timer interval in seconds |
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@type repeat: bool |
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@param repeat: Whether this is a repeating timer or one-off |
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""" |
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# TODO: Implement repeating timers |
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assert not repeat, "Repeating timers are not yet supported" |
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# Get new ID |
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self._timer_id_last += 1 |
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timer_id = self._timer_id_last |
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self._timer_add.append(Timer(owner, timer_id, time.time(), |
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float(interval), repeat)) |
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return timer_id |
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def RemoveTimer(self, timer_id): |
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"""Removes a timer. |
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@type timer_id: int |
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@param timer_id: Timer ID |
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""" |
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self._timer_remove.append(timer_id) |
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