openstack/oslo.service
Code Issues Proposed changes

Make signal handling order predictable

Browse Source 
Due to the unordered nature of sets, it is possible for signal
handlers like _gracefull_shutdown() to run first and clear the
_signal_handlers before other registered handlers have run.

This patch converts _signal_handlers from a set to a list and
then runs the handlers LIFO similar to how atexit functions are
run. Given that the handlers added in service.py are added after
clearing the signal_handlers, they are guaranteed to be the first
in the list and the last run.

Change-Id: Ief3ab2f56fa3d805296709e12e5f7a71560f7b6e
Closes-Bug: #2057809
Related-Bug: #2056366
Signed-off-by: Terry Wilson <twilson@redhat.com>
This commit is contained in:
Terry Wilson 2024-03-06 15:55:47 -06:00
parent f425dd1222
commit d026081ca4
1 changed files with 3 additions and 3 deletions
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6
oslo_service/service.py
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@ -142,7 +142,7 @@ class SignalHandler(metaclass=Singleton):
self.signals_to_name = dict(
(sigval, name)
for (name, sigval) in self._signals_by_name.items())
self._signal_handlers = collections.defaultdict(set)
self._signal_handlers = collections.defaultdict(list)
self.clear()
def clear(self):
@ -158,7 +158,7 @@ class SignalHandler(metaclass=Singleton):
if not self.is_signal_supported(sig):
return
signo = self._signals_by_name[sig]
self._signal_handlers[signo].add(handler)
self._signal_handlers[signo].append(handler)
signal.signal(signo, self._handle_signal)
def _handle_signal(self, signo, frame):
@ -237,7 +237,7 @@ class SignalHandler(metaclass=Singleton):
self.__hub_module_file = sys.modules[hub.__module__].__file__
def _handle_signal_cb(self, signo, frame):
for handler in self._signal_handlers[signo]:
for handler in reversed(self._signal_handlers[signo]):
handler(signo, frame)
def is_signal_supported(self, sig_name):