285 lines
9.1 KiB
Python
285 lines
9.1 KiB
Python
#
|
|
# threading.py: anaconda thread management
|
|
#
|
|
# Copyright (C) 2012
|
|
# Red Hat, Inc. All rights reserved.
|
|
#
|
|
# This program is free software; you can redistribute it and/or modify
|
|
# it under the terms of the GNU General Public License as published by
|
|
# the Free Software Foundation; either version 2 of the License, or
|
|
# (at your option) any later version.
|
|
#
|
|
# This program is distributed in the hope that it will be useful,
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
# GNU General Public License for more details.
|
|
#
|
|
# 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 threading
|
|
|
|
from pyanaconda.anaconda_loggers import get_module_logger
|
|
log = get_module_logger(__name__)
|
|
|
|
|
|
_WORKER_THREAD_PREFIX = "AnaWorkerThread"
|
|
|
|
|
|
class ThreadManager(object):
|
|
"""A singleton class for managing threads and processes.
|
|
|
|
Notes:
|
|
THE INSTANCE HAS TO BE CREATED IN THE MAIN THREAD!
|
|
|
|
This manager makes one assumption that contradicts python's
|
|
threading module documentation. In this class, we assume that thread
|
|
names are unique and meaningful. This is an okay assumption for us
|
|
to make given that anaconda is only ever going to have a handful of
|
|
special purpose threads.
|
|
"""
|
|
def __init__(self):
|
|
self._objs = {}
|
|
self._objs_lock = threading.RLock()
|
|
self._errors = {}
|
|
self._errors_lock = threading.RLock()
|
|
|
|
def __call__(self):
|
|
return self
|
|
|
|
def add(self, obj):
|
|
"""Given a Thread or Process object, add it to the list of known objects
|
|
and start it. It is assumed that obj.name is unique and descriptive.
|
|
"""
|
|
|
|
# we need to lock the thread dictionary when adding a new thread,
|
|
# so that callers can't get & join threads that are not yet started
|
|
with self._objs_lock:
|
|
if obj.name in self._objs:
|
|
raise KeyError("Cannot add thread '%s', a thread with the same name already running" % obj.name)
|
|
|
|
self._objs[obj.name] = obj
|
|
obj.start()
|
|
|
|
return obj.name
|
|
|
|
def remove(self, name):
|
|
"""Removes a thread from the list of known objects. This should only
|
|
be called when a thread exits, or there will be no way to get a
|
|
handle on it.
|
|
"""
|
|
with self._objs_lock:
|
|
self._objs.pop(name)
|
|
|
|
def exists(self, name):
|
|
"""Determine if a thread or process exists with the given name."""
|
|
|
|
# thread in the ThreadManager only officially exists once started
|
|
with self._objs_lock:
|
|
return name in self._objs
|
|
|
|
def get(self, name):
|
|
"""Given an object name, see if it exists and return the object.
|
|
Return None if no such object exists. Additionally, this method
|
|
will re-raise any uncaught exception in the thread.
|
|
"""
|
|
|
|
# without the lock it would be possible to get & join
|
|
# a thread that was not yet started
|
|
with self._objs_lock:
|
|
obj = self._objs.get(name)
|
|
if obj:
|
|
self.raise_if_error(name)
|
|
|
|
return obj
|
|
|
|
def wait(self, name):
|
|
"""Wait for the thread to exit and if the thread exited with an error
|
|
re-raise it here.
|
|
"""
|
|
|
|
ret_val = True
|
|
|
|
# we don't need a lock here,
|
|
# because get() acquires it itself
|
|
try:
|
|
self.get(name).join()
|
|
except AttributeError:
|
|
ret_val = False
|
|
# - if there is a thread object for the given name,
|
|
# we join it
|
|
# - if there is not a thread object for the given name,
|
|
# we get None, try to join it, suppress the AttributeError
|
|
# and return immediately
|
|
|
|
self.raise_if_error(name)
|
|
|
|
# return True if we waited for the thread, False otherwise
|
|
return ret_val
|
|
|
|
def wait_all(self):
|
|
"""Wait for all threads to exit and if there was an error re-raise it.
|
|
"""
|
|
with self._objs_lock:
|
|
names = list(self._objs.keys())
|
|
|
|
for name in names:
|
|
if self.get(name) == threading.current_thread():
|
|
continue
|
|
log.debug("Waiting for thread %s to exit", name)
|
|
self.wait(name)
|
|
|
|
if self.any_errors:
|
|
with self._errors_lock:
|
|
thread_names = ", ".join(thread_name for thread_name in self._errors.keys()
|
|
if self._errors[thread_name])
|
|
msg = "Unhandled errors from the following threads detected: %s" % thread_names
|
|
raise RuntimeError(msg)
|
|
|
|
def set_error(self, name, *exc_info):
|
|
"""Set the error data for a thread
|
|
|
|
The exception data is expected to be the tuple from sys.exc_info()
|
|
"""
|
|
with self._errors_lock:
|
|
self._errors[name] = exc_info
|
|
|
|
@property
|
|
def any_errors(self):
|
|
"""Return True of there have been any errors in any threads
|
|
"""
|
|
with self._errors_lock:
|
|
return any(self._errors.values())
|
|
|
|
def raise_if_error(self, name):
|
|
"""If a thread has failed due to an exception, raise it into the main
|
|
thread and remove it from errors.
|
|
"""
|
|
if name not in self._errors:
|
|
# no errors found for the thread
|
|
return
|
|
|
|
with self._errors_lock:
|
|
exc_info = self._errors.pop(name)
|
|
if exc_info:
|
|
raise exc_info[1]
|
|
|
|
def in_main_thread(self):
|
|
"""Return True if it is run in the main thread."""
|
|
return threading.current_thread() is threading.main_thread()
|
|
|
|
@property
|
|
def running(self):
|
|
""" Return the number of running threads.
|
|
|
|
:returns: number of running threads
|
|
:rtype: int
|
|
"""
|
|
with self._objs_lock:
|
|
return len(self._objs)
|
|
|
|
@property
|
|
def names(self):
|
|
""" Return the names of the running threads.
|
|
|
|
:returns: list of thread names
|
|
:rtype: list of strings
|
|
"""
|
|
with self._objs_lock:
|
|
return list(self._objs.keys())
|
|
|
|
def wait_for_error_threads(self):
|
|
"""
|
|
Waits for all threads that caused exceptions. In other words, waits for
|
|
exception handling (possibly interactive) to be finished.
|
|
|
|
"""
|
|
|
|
with self._errors_lock:
|
|
for thread_name in self._errors.keys():
|
|
thread = self._objs[thread_name]
|
|
thread.join()
|
|
|
|
|
|
class AnacondaThread(threading.Thread):
|
|
"""A threading.Thread subclass that exists only for a couple purposes:
|
|
|
|
(1) Make exceptions that happen in a thread invoke our exception handling
|
|
code as well. Otherwise, threads will silently die and we are doing
|
|
a lot of complicated code in them now.
|
|
|
|
(2) Remove themselves from the thread manager when completed.
|
|
|
|
(3) All created threads are made daemonic, which means anaconda will quit
|
|
when the main process is killed.
|
|
"""
|
|
|
|
# class-wide dictionary ensuring unique thread names
|
|
_prefix_thread_counts = dict()
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
# if neither name nor prefix is given, use the worker prefix
|
|
if "name" not in kwargs and "prefix" not in kwargs:
|
|
kwargs["prefix"] = _WORKER_THREAD_PREFIX
|
|
|
|
# if prefix is specified, use it to construct new thread name
|
|
prefix = kwargs.pop("prefix", None)
|
|
if prefix:
|
|
thread_num = self._prefix_thread_counts.get(prefix, 0) + 1
|
|
self._prefix_thread_counts[prefix] = thread_num
|
|
kwargs["name"] = prefix + str(thread_num)
|
|
|
|
if "fatal" in kwargs:
|
|
self._fatal = kwargs.pop("fatal")
|
|
else:
|
|
self._fatal = True
|
|
|
|
self._target_started_callback = kwargs.pop("target_started", None)
|
|
self._target_stopped_callback = kwargs.pop("target_stopped", None)
|
|
self._target_failed_callback = kwargs.pop("target_failed", None)
|
|
|
|
super().__init__(*args, **kwargs)
|
|
self.daemon = True
|
|
|
|
def _target_started(self):
|
|
log.info("Running Thread: %s (%s)", self.name, self.ident)
|
|
|
|
if self._target_started_callback:
|
|
self._target_started_callback()
|
|
|
|
def _target_stopped(self):
|
|
log.info("Thread Done: %s (%s)", self.name, self.ident)
|
|
|
|
if self._target_stopped_callback:
|
|
self._target_stopped_callback()
|
|
|
|
def _target_failed(self, *exc_info):
|
|
log.info("Thread Failed: %s (%s)", self.name, self.ident)
|
|
|
|
if self._fatal:
|
|
import sys
|
|
sys.excepthook(*exc_info)
|
|
else:
|
|
threadMgr.set_error(self.name, *exc_info)
|
|
|
|
if self._target_failed_callback:
|
|
self._target_failed_callback(*exc_info)
|
|
|
|
def run(self):
|
|
# http://bugs.python.org/issue1230540#msg25696
|
|
import sys
|
|
|
|
try:
|
|
self._target_started()
|
|
threading.Thread.run(self)
|
|
|
|
except: # pylint: disable=bare-except
|
|
self._target_failed(*sys.exc_info())
|
|
|
|
finally:
|
|
threadMgr.remove(self.name)
|
|
self._target_stopped()
|
|
|
|
|
|
threadMgr = ThreadManager()
|