1
0
mirror of git://sourceware.org/git/lvm2.git synced 2024-12-22 17:35:59 +03:00
lvm2/daemons/lvmdbusd/request.py
Tony Asleson 25abe41b00 lvmdbusd: Re-work error handling for run_cmd
Instead of lumping all the exceptions, break them out to handle the dbus
exceptions separately, to reduce the amount of debug information that ends
up in the journal that has questionable value.
2022-09-16 10:49:37 -05:00

168 lines
4.9 KiB
Python

# Copyright (C) 2015-2016 Red Hat, Inc. All rights reserved.
#
# This copyrighted material is made available to anyone wishing to use,
# modify, copy, or redistribute it subject to the terms and conditions
# of the GNU General Public License v.2.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import dbus
import threading
# noinspection PyUnresolvedReferences
from gi.repository import GLib
from .job import Job
from . import cfg
import traceback
from .utils import log_error, mt_async_call
class RequestEntry(object):
def __init__(self, tmo, method, arguments, cb, cb_error,
return_tuple=True, job_state=None):
self.method = method
self.arguments = arguments
self.cb = cb
self.cb_error = cb_error
self.timer_id = -1
self.lock = threading.RLock()
self.done = False
self._result = None
self._job = None
self._rc = 0
self._rc_error = None
self._return_tuple = return_tuple
self._job_state = job_state
if tmo < 0:
# Client is willing to block forever
pass
elif tmo == 0:
self._return_job()
else:
# Note: using 990 instead of 1000 for second to ms conversion to
# account for overhead. Goal is to return just before the
# timeout amount has expired. Better to be a little early than
# late.
self.timer_id = GLib.timeout_add(
tmo * 990, RequestEntry._request_timeout, self)
@staticmethod
def _request_timeout(r):
"""
Method which gets called when the timer runs out!
:param r: RequestEntry which timed out
:return: Result of timer_expired
"""
return r.timer_expired()
def _return_job(self):
# Return job is only called when we create a request object or when
# we pop a timer. In both cases we are running in the correct context
# and do not need to schedule the call back in main context.
self._job = Job(self, self._job_state)
cfg.om.register_object(self._job, True)
if self._return_tuple:
self.cb(('/', self._job.dbus_object_path()))
else:
self.cb(self._job.dbus_object_path())
def run_cmd(self):
try:
result = self.method(*self.arguments)
self.register_result(result)
except SystemExit as se:
self.register_error(-1, str(se), se)
raise se
except dbus.exceptions.DBusException as dbe:
# This is an expected error path when something goes awry that
# we handled
self.register_error(-1, str(dbe), dbe)
except Exception as e:
# Use the request entry to return the result as the client may
# have gotten a job by the time we hit an error
# Lets set the exception text as the error message and log the
# exception in the journal for figuring out what went wrong.
cfg.debug.dump()
cfg.flightrecorder.dump()
tb = ''.join(traceback.format_tb(e.__traceback__))
log_error("While processing %s: we encountered\n%s" % (str(self.method), tb))
log_error("Error returned to client: %s" % str(e))
self.register_error(-1, str(e), e)
def is_done(self):
with self.lock:
rc = self.done
return rc
def get_errors(self):
with self.lock:
return (self._rc, self._rc_error)
def result(self):
with self.lock:
if self.done:
return self._result
return '/'
def _reg_ending(self, result, error_rc=0, error_msg=None,
error_exception=None):
with self.lock:
self.done = True
if self.timer_id != -1:
# Try to prevent the timer from firing
GLib.source_remove(self.timer_id)
self._result = result
self._rc = error_rc
self._rc_error = error_msg
if not self._job:
# We finished and there is no job, so return result or error
# now!
# Note: If we don't have a valid cb or cbe, this indicates a
# request that doesn't need a response as we already returned
# one before the request was processed.
if error_rc == 0:
if self.cb:
if self._return_tuple:
mt_async_call(self.cb, (result, '/'))
else:
mt_async_call(self.cb, result)
else:
if self.cb_error:
if not error_exception:
if not error_msg:
error_exception = Exception(
"An error occurred, but no reason was "
"given, see service logs!")
else:
error_exception = Exception(error_msg)
mt_async_call(self.cb_error, error_exception)
else:
# We have a job and it's complete, indicate that it's done.
self._job.Complete = True
self._job = None
def register_error(self, error_rc, error_message, error_exception):
self._reg_ending('/', error_rc, error_message, error_exception)
def register_result(self, result):
self._reg_ending(result)
def timer_expired(self):
with self.lock:
# Set the timer back to -1 as we will get a warning if we try
# to remove a timer that doesn't exist
self.timer_id = -1
if not self.done:
# Create dbus job object and return path to caller
self._return_job()
else:
# The job is done, we have nothing to do
pass
return False