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authorJames Taylor <user234683@users.noreply.github.com>2018-09-14 19:32:27 -0700
committerJames Taylor <user234683@users.noreply.github.com>2018-09-14 19:32:27 -0700
commit4212164e91ba2f49583cf44ad623a29b36db8f77 (patch)
tree47aefe3c0162f03e0c823b43873356f69c1cd636 /python/gevent/_monitor.py
parent6ca20ff7010f2bafc7fefcb8cad982be27a8aeae (diff)
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diff --git a/python/gevent/_monitor.py b/python/gevent/_monitor.py
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+# Copyright (c) 2018 gevent. See LICENSE for details.
+from __future__ import print_function, absolute_import, division
+
+import os
+import sys
+
+from weakref import ref as wref
+
+from greenlet import getcurrent
+
+from gevent import config as GEVENT_CONFIG
+from gevent.monkey import get_original
+from gevent.events import notify
+from gevent.events import EventLoopBlocked
+from gevent.events import MemoryUsageThresholdExceeded
+from gevent.events import MemoryUsageUnderThreshold
+from gevent.events import IPeriodicMonitorThread
+from gevent.events import implementer
+
+from gevent._tracer import GreenletTracer
+from gevent._compat import thread_mod_name
+from gevent._compat import perf_counter
+
+
+
+__all__ = [
+ 'PeriodicMonitoringThread',
+]
+
+get_thread_ident = get_original(thread_mod_name, 'get_ident')
+start_new_thread = get_original(thread_mod_name, 'start_new_thread')
+thread_sleep = get_original('time', 'sleep')
+
+
+
+class MonitorWarning(RuntimeWarning):
+ """The type of warnings we emit."""
+
+
+class _MonitorEntry(object):
+
+ __slots__ = ('function', 'period', 'last_run_time')
+
+ def __init__(self, function, period):
+ self.function = function
+ self.period = period
+ self.last_run_time = 0
+
+ def __eq__(self, other):
+ return self.function == other.function and self.period == other.period
+
+ def __repr__(self):
+ return repr((self.function, self.period, self.last_run_time))
+
+
+@implementer(IPeriodicMonitorThread)
+class PeriodicMonitoringThread(object):
+ # This doesn't extend threading.Thread because that gets monkey-patched.
+ # We use the low-level 'start_new_thread' primitive instead.
+
+ # The amount of seconds we will sleep when we think we have nothing
+ # to do.
+ inactive_sleep_time = 2.0
+
+ # The absolute minimum we will sleep, regardless of
+ # what particular monitoring functions want to say.
+ min_sleep_time = 0.005
+
+ # The minimum period in seconds at which we will check memory usage.
+ # Getting memory usage is fairly expensive.
+ min_memory_monitor_period = 2
+
+ # A list of _MonitorEntry objects: [(function(hub), period, last_run_time))]
+ # The first entry is always our entry for self.monitor_blocking
+ _monitoring_functions = None
+
+ # The calculated min sleep time for the monitoring functions list.
+ _calculated_sleep_time = None
+
+ # A boolean value that also happens to capture the
+ # memory usage at the time we exceeded the threshold. Reset
+ # to 0 when we go back below.
+ _memory_exceeded = 0
+
+ # The instance of GreenletTracer we're using
+ _greenlet_tracer = None
+
+ def __init__(self, hub):
+ self._hub_wref = wref(hub, self._on_hub_gc)
+ self.should_run = True
+
+ # Must be installed in the thread that the hub is running in;
+ # the trace function is threadlocal
+ assert get_thread_ident() == hub.thread_ident
+ self._greenlet_tracer = GreenletTracer()
+
+ self._monitoring_functions = [_MonitorEntry(self.monitor_blocking,
+ GEVENT_CONFIG.max_blocking_time)]
+ self._calculated_sleep_time = GEVENT_CONFIG.max_blocking_time
+ # Create the actual monitoring thread. This is effectively a "daemon"
+ # thread.
+ self.monitor_thread_ident = start_new_thread(self, ())
+
+ # We must track the PID to know if your thread has died after a fork
+ self.pid = os.getpid()
+
+ def _on_fork(self):
+ # Pseudo-standard method that resolver_ares and threadpool
+ # also have, called by hub.reinit()
+ pid = os.getpid()
+ if pid != self.pid:
+ self.pid = pid
+ self.monitor_thread_ident = start_new_thread(self, ())
+
+ @property
+ def hub(self):
+ return self._hub_wref()
+
+
+ def monitoring_functions(self):
+ # Return a list of _MonitorEntry objects
+
+ # Update max_blocking_time each time.
+ mbt = GEVENT_CONFIG.max_blocking_time # XXX: Events so we know when this changes.
+ if mbt != self._monitoring_functions[0].period:
+ self._monitoring_functions[0].period = mbt
+ self._calculated_sleep_time = min(x.period for x in self._monitoring_functions)
+ return self._monitoring_functions
+
+ def add_monitoring_function(self, function, period):
+ if not callable(function):
+ raise ValueError("function must be callable")
+
+ if period is None:
+ # Remove.
+ self._monitoring_functions = [
+ x for x in self._monitoring_functions
+ if x.function != function
+ ]
+ elif period <= 0:
+ raise ValueError("Period must be positive.")
+ else:
+ # Add or update period
+ entry = _MonitorEntry(function, period)
+ self._monitoring_functions = [
+ x if x.function != function else entry
+ for x in self._monitoring_functions
+ ]
+ if entry not in self._monitoring_functions:
+ self._monitoring_functions.append(entry)
+ self._calculated_sleep_time = min(x.period for x in self._monitoring_functions)
+
+ def calculate_sleep_time(self):
+ min_sleep = self._calculated_sleep_time
+ if min_sleep <= 0:
+ # Everyone wants to be disabled. Sleep for a longer period of
+ # time than usual so we don't spin unnecessarily. We might be
+ # enabled again in the future.
+ return self.inactive_sleep_time
+ return max((min_sleep, self.min_sleep_time))
+
+ def kill(self):
+ if not self.should_run:
+ # Prevent overwriting trace functions.
+ return
+ # Stop this monitoring thread from running.
+ self.should_run = False
+ # Uninstall our tracing hook
+ self._greenlet_tracer.kill()
+
+ def _on_hub_gc(self, _):
+ self.kill()
+
+ def __call__(self):
+ # The function that runs in the monitoring thread.
+ # We cannot use threading.current_thread because it would
+ # create an immortal DummyThread object.
+ getcurrent().gevent_monitoring_thread = wref(self)
+
+ try:
+ while self.should_run:
+ functions = self.monitoring_functions()
+ assert functions
+ sleep_time = self.calculate_sleep_time()
+
+ thread_sleep(sleep_time)
+
+ # Make sure the hub is still around, and still active,
+ # and keep it around while we are here.
+ hub = self.hub
+ if not hub:
+ self.kill()
+
+ if self.should_run:
+ this_run = perf_counter()
+ for entry in functions:
+ f = entry.function
+ period = entry.period
+ last_run = entry.last_run_time
+ if period and last_run + period <= this_run:
+ entry.last_run_time = this_run
+ f(hub)
+ del hub # break our reference to hub while we sleep
+
+ except SystemExit:
+ pass
+ except: # pylint:disable=bare-except
+ # We're a daemon thread, so swallow any exceptions that get here
+ # during interpreter shutdown.
+ if not sys or not sys.stderr: # pragma: no cover
+ # Interpreter is shutting down
+ pass
+ else:
+ hub = self.hub
+ if hub is not None:
+ # XXX: This tends to do bad things like end the process, because we
+ # try to switch *threads*, which can't happen. Need something better.
+ hub.handle_error(self, *sys.exc_info())
+
+ def monitor_blocking(self, hub):
+ # Called periodically to see if the trace function has
+ # fired to switch greenlets. If not, we will print
+ # the greenlet tree.
+
+ # For tests, we return a true value when we think we found something
+ # blocking
+
+ did_block = self._greenlet_tracer.did_block_hub(hub)
+ if not did_block:
+ return
+
+ active_greenlet = did_block[1]
+ report = self._greenlet_tracer.did_block_hub_report(
+ hub, active_greenlet,
+ dict(greenlet_stacks=False, current_thread_ident=self.monitor_thread_ident))
+
+ stream = hub.exception_stream
+ for line in report:
+ # Printing line by line may interleave with other things,
+ # but it should also prevent a "reentrant call to print"
+ # when the report is large.
+ print(line, file=stream)
+
+ notify(EventLoopBlocked(active_greenlet, GEVENT_CONFIG.max_blocking_time, report))
+ return (active_greenlet, report)
+
+ def ignore_current_greenlet_blocking(self):
+ self._greenlet_tracer.ignore_current_greenlet_blocking()
+
+ def monitor_current_greenlet_blocking(self):
+ self._greenlet_tracer.monitor_current_greenlet_blocking()
+
+ def _get_process(self): # pylint:disable=method-hidden
+ try:
+ # The standard library 'resource' module doesn't provide
+ # a standard way to get the RSS measure, only the maximum.
+ # You might be tempted to try to compute something by adding
+ # together text and data sizes, but on many systems those come back
+ # zero. So our only option is psutil.
+ from psutil import Process, AccessDenied
+ # Make sure it works (why would we be denied access to our own process?)
+ try:
+ proc = Process()
+ proc.memory_full_info()
+ except AccessDenied: # pragma: no cover
+ proc = None
+ except ImportError:
+ proc = None
+
+ self._get_process = lambda: proc
+ return proc
+
+ def can_monitor_memory_usage(self):
+ return self._get_process() is not None
+
+ def install_monitor_memory_usage(self):
+ # Start monitoring memory usage, if possible.
+ # If not possible, emit a warning.
+ if not self.can_monitor_memory_usage():
+ import warnings
+ warnings.warn("Unable to monitor memory usage. Install psutil.",
+ MonitorWarning)
+ return
+
+ self.add_monitoring_function(self.monitor_memory_usage,
+ max(GEVENT_CONFIG.memory_monitor_period,
+ self.min_memory_monitor_period))
+
+ def monitor_memory_usage(self, _hub):
+ max_allowed = GEVENT_CONFIG.max_memory_usage
+ if not max_allowed:
+ # They disabled it.
+ return -1 # value for tests
+
+ rusage = self._get_process().memory_full_info()
+ # uss only documented available on Windows, Linux, and OS X.
+ # If not available, fall back to rss as an aproximation.
+ mem_usage = getattr(rusage, 'uss', 0) or rusage.rss
+
+ event = None # Return value for tests
+
+ if mem_usage > max_allowed:
+ if mem_usage > self._memory_exceeded:
+ # We're still growing
+ event = MemoryUsageThresholdExceeded(
+ mem_usage, max_allowed, rusage)
+ notify(event)
+ self._memory_exceeded = mem_usage
+ else:
+ # we're below. Were we above it last time?
+ if self._memory_exceeded:
+ event = MemoryUsageUnderThreshold(
+ mem_usage, max_allowed, rusage, self._memory_exceeded)
+ notify(event)
+ self._memory_exceeded = 0
+
+ return event
+
+ def __repr__(self):
+ return '<%s at %s in thread %s greenlet %r for %r>' % (
+ self.__class__.__name__,
+ hex(id(self)),
+ hex(self.monitor_thread_ident),
+ getcurrent(),
+ self._hub_wref())