--- /dev/null
+import errno
+import heapq
+import math
+import signal
+import sys
+import traceback
+
+arm_alarm = None
+if hasattr(signal, 'setitimer'):
+ def alarm_itimer(seconds):
+ signal.setitimer(signal.ITIMER_REAL, seconds)
+ arm_alarm = alarm_itimer
+else:
+ try:
+ import itimer
+ arm_alarm = itimer.alarm
+ except ImportError:
+ def alarm_signal(seconds):
+ signal.alarm(math.ceil(seconds))
+ arm_alarm = alarm_signal
+
+from eventlet import patcher
+from eventlet.hubs import timer, IOClosed
+from eventlet.support import greenlets as greenlet, clear_sys_exc_info
+time = patcher.original('time')
+
+g_prevent_multiple_readers = True
+
+READ = "read"
+WRITE = "write"
+
+
+def closed_callback(fileno):
+ """ Used to de-fang a callback that may be triggered by a loop in BaseHub.wait
+ """
+ # No-op.
+ pass
+
+
+class FdListener(object):
+
+ def __init__(self, evtype, fileno, cb, tb, mark_as_closed):
+ """ The following are required:
+ cb - the standard callback, which will switch into the
+ listening greenlet to indicate that the event waited upon
+ is ready
+ tb - a 'throwback'. This is typically greenlet.throw, used
+ to raise a signal into the target greenlet indicating that
+ an event was obsoleted by its underlying filehandle being
+ repurposed.
+ mark_as_closed - if any listener is obsoleted, this is called
+ (in the context of some other client greenlet) to alert
+ underlying filehandle-wrapping objects that they've been
+ closed.
+ """
+ assert (evtype is READ or evtype is WRITE)
+ self.evtype = evtype
+ self.fileno = fileno
+ self.cb = cb
+ self.tb = tb
+ self.mark_as_closed = mark_as_closed
+ self.spent = False
+ self.greenlet = greenlet.getcurrent()
+
+ def __repr__(self):
+ return "%s(%r, %r, %r, %r)" % (type(self).__name__, self.evtype, self.fileno,
+ self.cb, self.tb)
+ __str__ = __repr__
+
+ def defang(self):
+ self.cb = closed_callback
+ if self.mark_as_closed is not None:
+ self.mark_as_closed()
+ self.spent = True
+
+
+noop = FdListener(READ, 0, lambda x: None, lambda x: None, None)
+
+
+# in debug mode, track the call site that created the listener
+
+
+class DebugListener(FdListener):
+
+ def __init__(self, evtype, fileno, cb, tb, mark_as_closed):
+ self.where_called = traceback.format_stack()
+ self.greenlet = greenlet.getcurrent()
+ super(DebugListener, self).__init__(evtype, fileno, cb, tb, mark_as_closed)
+
+ def __repr__(self):
+ return "DebugListener(%r, %r, %r, %r, %r, %r)\n%sEndDebugFdListener" % (
+ self.evtype,
+ self.fileno,
+ self.cb,
+ self.tb,
+ self.mark_as_closed,
+ self.greenlet,
+ ''.join(self.where_called))
+ __str__ = __repr__
+
+
+def alarm_handler(signum, frame):
+ import inspect
+ raise RuntimeError("Blocking detector ALARMED at" + str(inspect.getframeinfo(frame)))
+
+
+class BaseHub(object):
+ """ Base hub class for easing the implementation of subclasses that are
+ specific to a particular underlying event architecture. """
+
+ SYSTEM_EXCEPTIONS = (KeyboardInterrupt, SystemExit)
+
+ READ = READ
+ WRITE = WRITE
+
+ def __init__(self, clock=time.time):
+ self.listeners = {READ: {}, WRITE: {}}
+ self.secondaries = {READ: {}, WRITE: {}}
+ self.closed = []
+
+ self.clock = clock
+ self.greenlet = greenlet.greenlet(self.run)
+ self.stopping = False
+ self.running = False
+ self.timers = []
+ self.next_timers = []
+ self.lclass = FdListener
+ self.timers_canceled = 0
+ self.debug_exceptions = True
+ self.debug_blocking = False
+ self.debug_blocking_resolution = 1
+
+ def block_detect_pre(self):
+ # shortest alarm we can possibly raise is one second
+ tmp = signal.signal(signal.SIGALRM, alarm_handler)
+ if tmp != alarm_handler:
+ self._old_signal_handler = tmp
+
+ arm_alarm(self.debug_blocking_resolution)
+
+ def block_detect_post(self):
+ if (hasattr(self, "_old_signal_handler") and
+ self._old_signal_handler):
+ signal.signal(signal.SIGALRM, self._old_signal_handler)
+ signal.alarm(0)
+
+ def add(self, evtype, fileno, cb, tb, mark_as_closed):
+ """ Signals an intent to or write a particular file descriptor.
+
+ The *evtype* argument is either the constant READ or WRITE.
+
+ The *fileno* argument is the file number of the file of interest.
+
+ The *cb* argument is the callback which will be called when the file
+ is ready for reading/writing.
+
+ The *tb* argument is the throwback used to signal (into the greenlet)
+ that the file was closed.
+
+ The *mark_as_closed* is used in the context of the event hub to
+ prepare a Python object as being closed, pre-empting further
+ close operations from accidentally shutting down the wrong OS thread.
+ """
+ listener = self.lclass(evtype, fileno, cb, tb, mark_as_closed)
+ bucket = self.listeners[evtype]
+ if fileno in bucket:
+ if g_prevent_multiple_readers:
+ raise RuntimeError(
+ "Second simultaneous %s on fileno %s "
+ "detected. Unless you really know what you're doing, "
+ "make sure that only one greenthread can %s any "
+ "particular socket. Consider using a pools.Pool. "
+ "If you do know what you're doing and want to disable "
+ "this error, call "
+ "eventlet.debug.hub_prevent_multiple_readers(False) - MY THREAD=%s; THAT THREAD=%s" % (
+ evtype, fileno, evtype, cb, bucket[fileno]))
+ # store off the second listener in another structure
+ self.secondaries[evtype].setdefault(fileno, []).append(listener)
+ else:
+ bucket[fileno] = listener
+ return listener
+
+ def _obsolete(self, fileno):
+ """ We've received an indication that 'fileno' has been obsoleted.
+ Any current listeners must be defanged, and notifications to
+ their greenlets queued up to send.
+ """
+ found = False
+ for evtype, bucket in self.secondaries.items():
+ if fileno in bucket:
+ for listener in bucket[fileno]:
+ found = True
+ self.closed.append(listener)
+ listener.defang()
+ del bucket[fileno]
+
+ # For the primary listeners, we actually need to call remove,
+ # which may modify the underlying OS polling objects.
+ for evtype, bucket in self.listeners.items():
+ if fileno in bucket:
+ listener = bucket[fileno]
+ found = True
+ self.closed.append(listener)
+ self.remove(listener)
+ listener.defang()
+
+ return found
+
+ def notify_close(self, fileno):
+ """ We might want to do something when a fileno is closed.
+ However, currently it suffices to obsolete listeners only
+ when we detect an old fileno being recycled, on open.
+ """
+ pass
+
+ def remove(self, listener):
+ if listener.spent:
+ # trampoline may trigger this in its finally section.
+ return
+
+ fileno = listener.fileno
+ evtype = listener.evtype
+ self.listeners[evtype].pop(fileno, None)
+ # migrate a secondary listener to be the primary listener
+ if fileno in self.secondaries[evtype]:
+ sec = self.secondaries[evtype].get(fileno, None)
+ if not sec:
+ return
+ self.listeners[evtype][fileno] = sec.pop(0)
+ if not sec:
+ del self.secondaries[evtype][fileno]
+
+ def mark_as_reopened(self, fileno):
+ """ If a file descriptor is returned by the OS as the result of some
+ open call (or equivalent), that signals that it might be being
+ recycled.
+
+ Catch the case where the fd was previously in use.
+ """
+ self._obsolete(fileno)
+
+ def remove_descriptor(self, fileno):
+ """ Completely remove all listeners for this fileno. For internal use
+ only."""
+ listeners = []
+ listeners.append(self.listeners[READ].pop(fileno, noop))
+ listeners.append(self.listeners[WRITE].pop(fileno, noop))
+ listeners.extend(self.secondaries[READ].pop(fileno, ()))
+ listeners.extend(self.secondaries[WRITE].pop(fileno, ()))
+ for listener in listeners:
+ try:
+ listener.cb(fileno)
+ except Exception:
+ self.squelch_generic_exception(sys.exc_info())
+
+ def close_one(self):
+ """ Triggered from the main run loop. If a listener's underlying FD was
+ closed somehow, throw an exception back to the trampoline, which should
+ be able to manage it appropriately.
+ """
+ listener = self.closed.pop()
+ if not listener.greenlet.dead:
+ # There's no point signalling a greenlet that's already dead.
+ listener.tb(IOClosed(errno.ENOTCONN, "Operation on closed file"))
+
+ def ensure_greenlet(self):
+ if self.greenlet.dead:
+ # create new greenlet sharing same parent as original
+ new = greenlet.greenlet(self.run, self.greenlet.parent)
+ # need to assign as parent of old greenlet
+ # for those greenlets that are currently
+ # children of the dead hub and may subsequently
+ # exit without further switching to hub.
+ self.greenlet.parent = new
+ self.greenlet = new
+
+ def switch(self):
+ cur = greenlet.getcurrent()
+ assert cur is not self.greenlet, 'Cannot switch to MAINLOOP from MAINLOOP'
+ switch_out = getattr(cur, 'switch_out', None)
+ if switch_out is not None:
+ try:
+ switch_out()
+ except:
+ self.squelch_generic_exception(sys.exc_info())
+ self.ensure_greenlet()
+ try:
+ if self.greenlet.parent is not cur:
+ cur.parent = self.greenlet
+ except ValueError:
+ pass # gets raised if there is a greenlet parent cycle
+ clear_sys_exc_info()
+ return self.greenlet.switch()
+
+ def squelch_exception(self, fileno, exc_info):
+ traceback.print_exception(*exc_info)
+ sys.stderr.write("Removing descriptor: %r\n" % (fileno,))
+ sys.stderr.flush()
+ try:
+ self.remove_descriptor(fileno)
+ except Exception as e:
+ sys.stderr.write("Exception while removing descriptor! %r\n" % (e,))
+ sys.stderr.flush()
+
+ def wait(self, seconds=None):
+ raise NotImplementedError("Implement this in a subclass")
+
+ def default_sleep(self):
+ return 60.0
+
+ def sleep_until(self):
+ t = self.timers
+ if not t:
+ return None
+ return t[0][0]
+
+ def run(self, *a, **kw):
+ """Run the runloop until abort is called.
+ """
+ # accept and discard variable arguments because they will be
+ # supplied if other greenlets have run and exited before the
+ # hub's greenlet gets a chance to run
+ if self.running:
+ raise RuntimeError("Already running!")
+ try:
+ self.running = True
+ self.stopping = False
+ while not self.stopping:
+ while self.closed:
+ # We ditch all of these first.
+ self.close_one()
+ self.prepare_timers()
+ if self.debug_blocking:
+ self.block_detect_pre()
+ self.fire_timers(self.clock())
+ if self.debug_blocking:
+ self.block_detect_post()
+ self.prepare_timers()
+ wakeup_when = self.sleep_until()
+ if wakeup_when is None:
+ sleep_time = self.default_sleep()
+ else:
+ sleep_time = wakeup_when - self.clock()
+ if sleep_time > 0:
+ self.wait(sleep_time)
+ else:
+ self.wait(0)
+ else:
+ self.timers_canceled = 0
+ del self.timers[:]
+ del self.next_timers[:]
+ finally:
+ self.running = False
+ self.stopping = False
+
+ def abort(self, wait=False):
+ """Stop the runloop. If run is executing, it will exit after
+ completing the next runloop iteration.
+
+ Set *wait* to True to cause abort to switch to the hub immediately and
+ wait until it's finished processing. Waiting for the hub will only
+ work from the main greenthread; all other greenthreads will become
+ unreachable.
+ """
+ if self.running:
+ self.stopping = True
+ if wait:
+ assert self.greenlet is not greenlet.getcurrent(), "Can't abort with wait from inside the hub's greenlet."
+ # schedule an immediate timer just so the hub doesn't sleep
+ self.schedule_call_global(0, lambda: None)
+ # switch to it; when done the hub will switch back to its parent,
+ # the main greenlet
+ self.switch()
+
+ def squelch_generic_exception(self, exc_info):
+ if self.debug_exceptions:
+ traceback.print_exception(*exc_info)
+ sys.stderr.flush()
+ clear_sys_exc_info()
+
+ def squelch_timer_exception(self, timer, exc_info):
+ if self.debug_exceptions:
+ traceback.print_exception(*exc_info)
+ sys.stderr.flush()
+ clear_sys_exc_info()
+
+ def add_timer(self, timer):
+ scheduled_time = self.clock() + timer.seconds
+ self.next_timers.append((scheduled_time, timer))
+ return scheduled_time
+
+ def timer_canceled(self, timer):
+ self.timers_canceled += 1
+ len_timers = len(self.timers) + len(self.next_timers)
+ if len_timers > 1000 and len_timers / 2 <= self.timers_canceled:
+ self.timers_canceled = 0
+ self.timers = [t for t in self.timers if not t[1].called]
+ self.next_timers = [t for t in self.next_timers if not t[1].called]
+ heapq.heapify(self.timers)
+
+ def prepare_timers(self):
+ heappush = heapq.heappush
+ t = self.timers
+ for item in self.next_timers:
+ if item[1].called:
+ self.timers_canceled -= 1
+ else:
+ heappush(t, item)
+ del self.next_timers[:]
+
+ def schedule_call_local(self, seconds, cb, *args, **kw):
+ """Schedule a callable to be called after 'seconds' seconds have
+ elapsed. Cancel the timer if greenlet has exited.
+ seconds: The number of seconds to wait.
+ cb: The callable to call after the given time.
+ *args: Arguments to pass to the callable when called.
+ **kw: Keyword arguments to pass to the callable when called.
+ """
+ t = timer.LocalTimer(seconds, cb, *args, **kw)
+ self.add_timer(t)
+ return t
+
+ def schedule_call_global(self, seconds, cb, *args, **kw):
+ """Schedule a callable to be called after 'seconds' seconds have
+ elapsed. The timer will NOT be canceled if the current greenlet has
+ exited before the timer fires.
+ seconds: The number of seconds to wait.
+ cb: The callable to call after the given time.
+ *args: Arguments to pass to the callable when called.
+ **kw: Keyword arguments to pass to the callable when called.
+ """
+ t = timer.Timer(seconds, cb, *args, **kw)
+ self.add_timer(t)
+ return t
+
+ def fire_timers(self, when):
+ t = self.timers
+ heappop = heapq.heappop
+
+ while t:
+ next = t[0]
+
+ exp = next[0]
+ timer = next[1]
+
+ if when < exp:
+ break
+
+ heappop(t)
+
+ try:
+ if timer.called:
+ self.timers_canceled -= 1
+ else:
+ timer()
+ except self.SYSTEM_EXCEPTIONS:
+ raise
+ except:
+ self.squelch_timer_exception(timer, sys.exc_info())
+ clear_sys_exc_info()
+
+ # for debugging:
+
+ def get_readers(self):
+ return self.listeners[READ].values()
+
+ def get_writers(self):
+ return self.listeners[WRITE].values()
+
+ def get_timers_count(hub):
+ return len(hub.timers) + len(hub.next_timers)
+
+ def set_debug_listeners(self, value):
+ if value:
+ self.lclass = DebugListener
+ else:
+ self.lclass = FdListener
+
+ def set_timer_exceptions(self, value):
+ self.debug_exceptions = value
Code Review / packages / trusty / python-eventlet.git / blobdiff