/usr/lib/python3/dist-packages/ginga/misc/Task.py is in python3-ginga 2.6.1-2.
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# Task.py -- Basic command pattern and thread pool implementation.
#
# This is open-source software licensed under a BSD license.
# Please see the file LICENSE.txt for details.
#
from __future__ import absolute_import, print_function
from ..util import six
from ..util.six.moves import map, zip
import sys
import time
import os
if six.PY2:
import thread
import Queue
else:
import _thread as thread
import queue as Queue
# NOTE: See http://bugs.python.org/issue7946
# we cannot effectively use threading for loading files/network/etc.
# without setting the switchinterval down on python 3 due to the new
# GIL implementation
_swival = 0.000001
sys.setswitchinterval(_swival)
import threading
import traceback
class TaskError(Exception):
"""Exception generated for task errors"""
pass
class TaskTimeout(TaskError):
"""Exception generated when timing out waiting on a task"""
pass
class UserTaskException(Exception):
pass
# ------------ BASIC TASKS ------------
class Task(object):
"""This class implements a basic Task (command) abstraction. The
methods define the interface for starting, cancelling, waiting on a
task, etc.
"""
def __init__(self):
"""
The constructor sets bare essentials for a Task object. See the
initialize() and start() methods.
"""
self.ev_done = threading.Event()
self.callbacks = Queue.Queue()
self.tag = None
self.logger = None
self.threadPool = None
# Lock for task state critical sections
self.tlock = threading.RLock()
# Parent task can set this (or add to it) explicitly to determine
# which values will be copied when it calls initialize() on a child
# task.
self.shares = ['logger', 'threadPool', 'shares']
super(Task, self).__init__()
def initialize(self, taskParent, override=None):
"""This method initializes a task for (re)use. taskParent is the
object instance of the parent task, or a 'task environment' (something
that runs tasks).
If subclass overrides this method, it should call the superclass
method at some point.
- Copy shared data from taskParent, overriding items from _override_
if they are present there ('contagion' of task values).
- Generate a unique tag, to be used with the Gen2 Monitor.
- Clear done event, initialize times and result.
"""
# For now, punt if we have no apparent parent
if taskParent and hasattr(taskParent, 'shares'):
# Copy some variables from our parent task, unless they are being
# overridden explicitly. Using this general "contagion" mechanism,
# a task can cause it's children to have values available to them
# without passing them explicitly.
for var in taskParent.shares:
if override and var in override:
self.__dict__[var] = override[var]
else:
#print "COPYING VAR FROM PARENT: %s(%s)" % (var, str(taskParent.__dict__[var]))
self.__dict__[var] = taskParent.__dict__[var]
else:
#raise TaskError("Cannot initialize task without a taskParent!")
pass
# Generate our own unique tag. 'tagger' should have been transmitted
# from the parent task
if not self.tag:
try:
self.tag = str(taskParent) + '.' + self.tagger.get_tag(self)
except:
# Failed--fall back to internal tagger
self.tag = get_tag(taskParent)
# Some per-task specific initialization
self.ev_done.clear()
self.starttime = time.time()
self.endtime = 0
self.totaltime = 0
self.result = None
return self.tag
def start(self):
"""This method starts a task executing and returns immediately.
Subclass should override this method, if it has an asynchronous
way to start the task and return immediately.
"""
if self.threadPool:
self.threadPool.addTask(self)
# Lets other threads have a chance to run
time.sleep(0)
else:
raise TaskError("start(): nothing to start for task %s" % self)
def init_and_start(self, taskParent, override={}):
"""Convenience method to initialize and start a task.
"""
tag = self.initialize(taskParent, override=override)
self.start()
return tag
def check_state(self):
"""Abstract method that should check for pause, cancellation, or
any other sort of preemption event.
"""
pass
def extend_shares(self, varlist):
shares = set(self.shares)
for var in varlist:
if hasattr(self, var):
shares.add(var)
self.shares = shares
def stop(self):
"""This method cancels an executing task (if possible).
Subclass should override this method.
Return True if task could be cancelled, False if not?
"""
raise TaskError("Task %s: subclass should override stop() method!" % (
self))
def pause(self):
"""This method pauses an executing task (if possible).
Subclass should override this method.
Return True if task could be paused, False if not?
"""
raise TaskError("Task %s: subclass should override pause() method!" % (
self))
def resume(self):
"""This method resumes an executing task (if possible).
Subclass should override this method, should not call super.resume().
Return True if task could be resumed, False if not?
"""
raise TaskError("Task %s: subclass should override resume() method!" % (
self))
def wait(self, timeout=None):
"""This method waits for an executing task to finish.
Subclass can override this method if necessary.
"""
self.ev_done.wait(timeout=timeout)
if not self.ev_done.isSet():
raise TaskTimeout("Task %s timed out." % self)
# --> self.result is set
# If it is an exception, then raise it in this waiter
if isinstance(self.result, Exception):
raise self.result
# Release waiters and perform callbacks
# done() has already been called, because of self.ev_done check
# "asynchronous" tasks should could call done() here
#self.done(self.result)
return self.result
def step(self):
"""If a task has a way of stepping through an operation. It can
implement this method. Subclass should not call super.step().
"""
raise TaskError("Task %s: subclass should override step() method!" % \
self)
def execute(self):
"""This method does the work of a task (if executed by the
thread pool) and returns when it is finished. *** Subclass should
override this method! *** It should take no arguments, and can
return anything.
"""
raise TaskError("Task %s: subclass should override execute() method!" % \
self)
def done(self, result, noraise=False):
"""This method is called when a task has finished executing.
Subclass can override this method if desired, but should call
superclass method at the end.
"""
# [??] Should this be in a critical section?
# Has done() already been called on this task?
if self.ev_done.isSet():
# ??
if isinstance(self.result, Exception) and (not noraise):
raise self.result
return self.result
# calculate running time and other finalization
self.endtime = time.time()
try:
self.totaltime = self.endtime - self.starttime
except AttributeError:
# task was not initialized properly
self.totaltime = 0.0
self.result = result
# Release thread waiters
self.ev_done.set()
# Perform callbacks for event-style waiters
self.do_callbacks()
# If the result is an exception, then our final act is to raise
# it in the caller, unless the caller explicitly supressed that
if isinstance(result, Exception) and (not noraise):
raise result
return result
def register_callback(self, fn, args=None):
"""This method is called to register a callback function to be
called when a task terminates.
Subclass should probably not override this method.
"""
if args is None:
args = []
if callable(fn):
self.callbacks.put((fn, args))
else:
raise TaskError("Function argument is not a callable: %s" % \
str(fn))
def do_callbacks(self):
"""Makes callbacks on all registered functions waiting on this task.
"""
while not self.callbacks.empty():
(fn, rest) = self.callbacks.get()
args = [self.result]
args.extend(rest)
fn(*args)
def get_tag(self):
"""This is only valid AFTER initialize() has been called on the task.
"""
return self.tag
def __str__(self):
"""Returns a string representation of a task (e.g. for debugging).
Subclass can override this method if desired.
"""
return str(self.tag)
def __lt__(self, other):
return False
def getExecutionTime(self):
return self.totaltime
def runTask(self, task, timeout=None):
"""Run a child task to completion. Returns the result of
the child task.
"""
# Initialize the task.
task.initialize(self)
# Start the task.
task.start()
# Lets other threads run
time.sleep(0)
# Wait for it to finish.
res = task.wait(timeout=timeout)
# Now we're done
return res
def run(self, task, timeout=None):
"""Run a child task to completion. Returns the result of
the child task. Simply calls runTask().
"""
return self.runTask(task, timeout=timeout)
# For testing...
class printTask(Task):
"""Simple task that prints msg."""
def __init__(self, msg):
self.msg = msg
super(printTask, self).__init__()
def execute(self):
print(self.msg)
class sleepTask(Task):
"""Simple task that sleeps for delay seconds."""
def __init__(self, delay):
self.delay = delay
super(sleepTask, self).__init__()
def execute(self):
self.ev_done.wait(timeout=self.delay)
class FuncTask(Task):
"""Simple task that calls func and returns func's return value."""
def __init__(self, func, args, kwdargs, logger=None):
self.func = func
self.args = args
self.kwdargs = kwdargs
self.logger = logger
super(FuncTask, self).__init__()
def execute(self):
if self.logger:
# Cap logging size around 500 characters
s_args = str(self.args)
if len(s_args) > 500:
s_args = s_args[:500]
s_kwdargs = str(self.kwdargs)
if len(s_kwdargs) > 500:
s_kwdargs = s_kwdargs[:500]
self.logger.debug("Running %s(%s, %s)" % (
self.func.__name__, s_args, s_kwdargs))
s_args = None
s_kwdargs = None
try:
res = self.func(*self.args, **self.kwdargs)
self.done(res)
if self.logger:
self.logger.debug("Function returned %s" % (
str(res)))
except Exception as e:
if self.logger:
self.logger.error("Task '%s' terminated with exception: %s" % \
(str(self), str(e)))
try:
(type, value, tb) = sys.exc_info()
self.logger.error("Traceback:\n%s" % \
"".join(traceback.format_tb(tb)))
tb = None
except Exception:
self.logger.error("Traceback information unavailable.")
self.done(e)
class FuncTask2(FuncTask):
"""Simple task that calls func and returns func's return value.
This version lets you specify the positional and keyword arguments
more naturally 'in place' in the constructor.
"""
def __init__(self, func, *args, **kwdargs):
super(FuncTask2, self).__init__(func, args, kwdargs)
def set_logger(self, logger):
self.logger = logger
def make_tasker(func):
"""make_tasker takes a callable (function, method, etc.) and returns
a new factory function for generating tasks. Each factory function is
designed to consume its arguments and return a task that, when executed,
will call the function upon the arguments.
TODO: deprecate this and just use FuncTask, which is easier to
understand--must change a number of programs first.
"""
def anonFunc(*args, **kwdargs):
class anonTask(Task):
def execute(self):
self.logger.debug("Executing fn %s" % func)
try:
val = func(*args, **kwdargs)
self.logger.debug("Done executing fn %s" % func)
return val
except Exception as e:
# Log error message and re-raise exception.
self.logger.error("fn %s raised exception: %s" % (
func, str(e)))
raise e
return anonTask()
return anonFunc
# ------------ COMPOUND TASKS ------------
class SequentialTaskset(Task):
"""Compound task that runs a series of tasks sequentially.
"""
def __init__(self, taskseq):
super(SequentialTaskset, self).__init__()
self.tasklist = list(taskseq)
def initialize(self, taskParent, **kwdargs):
self.index = 0
super(SequentialTaskset, self).initialize(taskParent, **kwdargs)
def step(self):
"""Run the next child task and wait for completion (no timeout)."""
if self.index >= len(self.tasklist):
raise TaskError("step(): sequential compound task %s finished" % self)
self.check_state()
# Select next task from the set and advance the index
self.task = self.tasklist[self.index]
self.index += 1
return self.runTask(self.task)
def execute(self):
"""Run all child tasks, in order, waiting for completion of each.
Return the result of the final child task's execution.
"""
while self.index < len(self.tasklist):
res = self.step()
self.logger.debug('SeqSet task %i has completed with result %s' % \
(self.index,res))
# Returns result of last task to quit
return res
def stop(self):
"""Interrupt/cancel execution, but will allow current child task
to complete."""
#self.ev_intr.set()
try:
self.task.stop()
except TaskError as e:
self.logger.error("Error cancelling child task: %s" % (str(e)))
def addTask(self, task):
"""Append a task to the task sequence. If the SequentialTaskset has
already completed execution, this will do nothing unless it is
restarted (initialize(), start()).
"""
self.tasklist.append(task)
class oldConcurrentAndTaskset(Task):
"""Compound task that runs a set of tasks concurrently, and does not
return until they all terminate.
"""
def __init__(self, taskseq):
super(oldConcurrentAndTaskset, self).__init__()
self.taskseq = taskseq
self.ev_intr = threading.Event()
# Used to synchronize compound task termination
self.regcond = threading.Condition()
def execute(self):
"""Run all child tasks concurrently in separate threads.
Return 0 after all child tasks have completed execution.
"""
self.count = 0
self.taskset = []
self.results = {}
self.totaltime = time.time()
# Register termination callbacks for all my child tasks.
for task in self.taskseq:
self.taskset.append(task)
task.register_callback(self.child_done, args=[self.count, task])
self.count += 1
self.numtasks = self.count
# Now start each child task.
with self.regcond:
for task in self.taskset:
task.initialize(self)
task.start()
# Account for time needed to start subtasks
self.totaltime = time.time() - self.totaltime
# Now give up the critical section and wait for last child
# task to terminate.
while self.count > 0:
self.regcond.wait()
# Scan results for errors (exceptions) and raise the first one we find
for key in self.results.keys():
value = self.results[key]
if isinstance(value, Exception):
(count, task) = key
self.logger.error("Child task %s terminated with exception: %s" % (
task.tag, str(value)))
raise value
return 0
def child_done(self, result, count, task):
"""Acquire the condition variable for the compound task object.
Decrement the thread count. If we are the last thread to
finish, release compound task thread, which is blocked in execute().
"""
with self.regcond:
self.logger.debug('Concurrent task %d/%d has completed' % (
self.count, self.numtasks))
self.count -= 1
self.taskset.remove(task)
self.totaltime += task.getExecutionTime()
self.results[(count, task)] = result
if self.count <= 0:
self.regcond.notifyAll()
def stop(self):
"""Call stop() on all child tasks, and ignore TaskError exceptions.
Behavior depends on what the child tasks' stop() method does."""
for task in self.taskset:
try:
task.stop()
except TaskError as e:
# Task does not have a way to stop it.
# TODO: notify who?
pass
def addTask(self, task):
"""Add a task to the task set.
"""
with self.regcond:
self.taskset.append(task)
task.register_callback(self.child_done, args=[self.numtasks, task])
self.numtasks += 1
self.count += 1
task.initialize(self)
task.start()
class newConcurrentAndTaskset(Task):
"""Compound task that runs a set of tasks concurrently, and does not
return until they all terminate.
"""
def __init__(self, taskseq):
super(newConcurrentAndTaskset, self).__init__()
self.taskseq = taskseq
# tuning value for polling inefficiency
self.idletime = 0.001
# internal mutex
self._lock_c = threading.RLock()
def execute(self):
"""Run all child tasks concurrently in separate threads.
Return last result after all child tasks have completed execution.
"""
with self._lock_c:
self.count = 0
self.numtasks = 0
self.taskset = []
self.results = {}
self.totaltime = time.time()
# Start all tasks
for task in self.taskseq:
self.taskset.append(task)
self.numtasks += 1
task.init_and_start(self)
num_tasks = self.getNumTasks()
# Wait on each task to clean up results
while num_tasks > 0:
self.check_state()
for i in range(num_tasks):
try:
try:
task = self.getTask(i)
except IndexError:
# A task got deleted from the set. Jump back out
# to outer loop and repoll the number of tasks
break
#self.logger.debug("waiting on %s" % task)
res = task.wait(timeout=self.idletime)
#self.logger.debug("finished: %s" % task)
self.child_done(res, task)
except TaskTimeout:
continue
except Exception as e:
#self.logger.warning("Subtask propagated exception: %s" % str(e))
self.child_done(e, task)
continue
# wait a bit and try again
#self.ev_quit.wait(self.idletime)
# re-get number of tasks, in case some were added or deleted
num_tasks = self.getNumTasks()
# Scan results for errors (exceptions) and raise the first one we find
for key in self.results.keys():
value = self.results[key]
if isinstance(value, Exception):
(count, task) = key
self.logger.error("Child task %s terminated with exception: %s" % (
task.tag, str(value)))
raise value
# Return value of last child to complete
return value
def child_done(self, result, task):
with self._lock_c:
self.count += 1
self.logger.debug('Concurrent task %d/%d has completed' % (
self.count, self.numtasks))
self.taskset.remove(task)
self.totaltime += task.getExecutionTime()
self.results[(self.count, task)] = result
def stop(self):
"""Call stop() on all child tasks, and ignore TaskError exceptions.
Behavior depends on what the child tasks' stop() method does."""
with self._lock_c:
for task in self.taskset:
try:
task.stop()
except TaskError as e:
# Task does not have a way to stop it.
# TODO: notify who?
pass
# stop ourself
#self.ev_intr.set()
def addTask(self, task):
"""Add a task to the task set.
"""
# Try to start task first. If it fails then we don't need to
# undo adding it to taskset
task.initialize(self)
task.start()
with self._lock_c:
self.numtasks += 1
self.taskset.append(task)
def getTask(self, i):
with self._lock_c:
return self.taskset[i]
def getNumTasks(self):
"""Get the set of active tasks.
"""
with self._lock_c:
return len(self.taskset)
class ConcurrentAndTaskset(newConcurrentAndTaskset):
pass
class QueueTaskset(Task):
"""Compound task that runs a set of tasks that it reads from a queue
concurrently. If _waitflag_ is True, then it will run each task to
completion before starting the next task.
"""
def __init__(self, queue, waitflag=True, timeout=0.1, ev_quit=None):
super(QueueTaskset, self).__init__()
self.queue = queue
self.waitflag = waitflag
self.lock = threading.RLock()
self.timeout = timeout
self.task = None
self.ev_cancel = threading.Event()
self.ev_pause = threading.Event()
if ev_quit == None:
ev_quit = threading.Event()
self.ev_quit = ev_quit
def flush(self):
# Flush queue of pending tasks
self.logger.debug("Flushing queue.")
while True:
try:
self.queue.get(block=False)
except Queue.Empty:
break
def stop(self):
self.flush()
#self.ev_intr.set()
try:
if self.task:
self.task.stop()
except TaskError as e:
#self.logger.error("Error cancelling child task: %s" % (str(e)))
pass
# put termination sentinel
self.queue.put(None)
def stop_child(self):
self.flush()
try:
if self.task:
self.task.stop()
except TaskError as e:
#self.logger.error("Error cancelling child task: %s" % (str(e)))
pass
def execute(self):
self.count = 0
self.totaltime = 0
self.logger.debug("Queue Taskset starting")
while not self.ev_quit.isSet():
try:
self.check_state()
task = self.queue.get(block=True, timeout=self.timeout)
if task == None:
# termination sentinel
break
self.task = task
task.register_callback(self.child_done, args=[task])
with self.lock:
self.count += 1
self.ev_cancel.clear()
try:
task.initialize(self)
self.logger.debug("Starting task '%s'" % str(task))
task.start()
if self.waitflag:
res = task.wait()
self.logger.debug("Task %s terminated with result %s" % (
(str(task), str(res))))
except Exception as e:
self.logger.error("Task '%s' terminated with exception: %s" % \
(str(task), str(e)))
try:
(type, value, tb) = sys.exc_info()
self.logger.debug("Traceback:\n%s" % \
"".join(traceback.format_tb(tb)))
# NOTE: to avoid creating a cycle that might cause
# problems for GC--see Python library doc for sys
# module
tb = None
except Exception as e:
self.logger.debug("Traceback information unavailable.")
# If task raised exception then it didn't call done,
task.done(e, noraise=True)
except Queue.Empty:
# No task available. Continue trying to get one.
continue
# TODO: should we wait for self.count > 0?
self.logger.debug("Queue Taskset terminating")
return self.result
def child_done(self, result, task):
with self.lock:
self.count -= 1
self.totaltime += task.getExecutionTime()
self.result = result
def cancel(self):
self.flush()
super(QueueTaskset, self).cancel()
def addTask(self, task):
self.queue.put(task)
# ------------ PRIORITY QUEUES ------------
class PriorityQueue(Queue.PriorityQueue):
pass
# ------------ WORKER THREADS ------------
class _WorkerReset(Exception):
"""Local exception used to reset a worker thread."""
pass
class WorkerThread(object):
"""Container for a thread in which to call the execute() method of a task.
A WorkerThread object waits on the task queue, executes a task when it
appears, and repeats. A call to start() is necessary to start servicing
the queue, and a call to stop() will terminate the service.
"""
def __init__(self, queue, logger=None, ev_quit=None,
timeout=0.2, tpool=None):
self.queue = queue
self.logger = logger
self.timeout = timeout
if ev_quit:
self.ev_quit = ev_quit
else:
self.ev_quit = threading.Event()
self.tpool = tpool
self.lock = threading.RLock()
self.status = 'stopped'
self.time_start = 0.0
def setstatus(self, status):
"""Sets our status field so that others can inquire what we are doing.
Set of status:
starting, idle
"""
with self.lock:
self.status = status
def getstatus(self):
"""Returns our status--a string describing what we are doing.
"""
with self.lock:
return (self.status, self.time_start)
def execute(self, task):
"""Execute a task.
"""
taskid = str(task)
res = None
try:
# Try to run the task. If we catch an exception, then
# it becomes the result.
self.time_start = time.time()
self.setstatus('executing %s' % taskid)
self.logger.debug("now executing task '%s'" % taskid)
try:
res = task.execute()
except UserTaskException as e:
res = e
except Exception as e:
self.logger.error("Task '%s' raised exception: %s" % \
(str(task), str(e)))
res = e
try:
(type, value, tb) = sys.exc_info()
self.logger.debug("Traceback:\n%s" % \
"".join(traceback.format_tb(tb)))
# NOTE: to avoid creating a cycle that might cause
# problems for GC--see Python library doc for sys
# module
tb = None
except Exception as e:
self.logger.debug("Traceback information unavailable.")
finally:
self.logger.debug("done executing task '%s'" % str(task))
self.setstatus('cleaning %s' % taskid)
# Wake up waiters on other threads
task.done(res, noraise=True)
self.time_start = 0.0
self.setstatus('idle')
# Basic task execution loop. Dequeue a task and run it, then look
# for another one
def taskloop(self):
self.setstatus('starting')
self.logger.debug('Starting worker thread loop.')
# If we were handed a thread pool upon startup, then register
# ourselves with it.
if self.tpool:
self.tpool.register_up()
try:
self.setstatus('idle')
while not self.ev_quit.isSet():
try:
# Wait on our queue for a task; will timeout in
# self.timeout secs
(priority, task) = self.queue.get(block=True,
timeout=self.timeout)
if task == None:
# termination sentinel
self.queue.put((priority, task))
break
self.execute(task)
except _WorkerReset:
self.logger.info("Worker reset!")
except Queue.Empty as e:
# Reach here when we time out waiting for a task
pass
finally:
self.logger.debug('Stopping worker thread loop.')
if self.tpool:
self.tpool.register_dn()
self.setstatus('stopped')
def start(self):
self.thread = threading.Thread(target=self.taskloop, args=[])
self.thread.start()
def stop(self):
# Put termination sentinal on queue
self.queue.put((priority, task))
self.ev_quit.set()
# ------------ THREAD POOL ------------
class ThreadPool(object):
"""A simple thread pool for executing tasks asynchronously.
self.status states:
down no threads are ready for service
up all threads are ready for service
start threads are starting, but not all of them are up yet
stop threads are stopping, but not all of them are down yet
"""
def __init__(self, numthreads=1, logger=None, ev_quit=None,
workerClass=WorkerThread):
self.numthreads = numthreads
self.logger = logger
if ev_quit:
self.ev_quit = ev_quit
else:
self.ev_quit = threading.Event()
self.lock = threading.RLock()
self.workerClass = workerClass
self.queue = PriorityQueue()
self.workers = []
self.tids = []
# Used to synchronize thread pool startup (see register() method)
self.regcond = threading.Condition()
self.runningcount = 0
self.status = 'down'
def startall(self, wait=False, **kwdargs):
"""Start all of the threads in the thread pool. If _wait_ is True
then don't return until all threads are up and running. Any extra
keyword arguments are passed to the worker thread constructor.
"""
self.logger.debug("startall called")
with self.regcond:
while self.status != 'down':
if self.status in ('start', 'up') or self.ev_quit.isSet():
# For now, abandon additional request to start
self.logger.error("ignoring duplicate request to start thread pool")
return
self.logger.debug("waiting for threads: count=%d" % \
self.runningcount)
self.regcond.wait()
#assert(self.status == 'down')
if self.ev_quit.isSet():
return
self.runningcount = 0
self.status = 'start'
self.workers = []
if wait:
tpool = self
else:
tpool = None
# Start all worker threads
self.logger.debug("starting threads in thread pool")
for i in range(self.numthreads):
t = self.workerClass(self.queue, logger=self.logger,
ev_quit=self.ev_quit, tpool=tpool,
**kwdargs)
self.workers.append(t)
t.start()
# if started with wait=True, then expect that threads will register
# themselves and last one up will set status to "up"
if wait:
# Threads are on the way up. Wait until last one starts.
while self.status != 'up' and not self.ev_quit.isSet():
self.logger.debug("waiting for threads: count=%d" % \
self.runningcount)
self.regcond.wait()
else:
# otherwise, we just assume the pool is up
self.status = 'up'
self.logger.debug("startall done")
def addThreads(self, numthreads, **kwdargs):
with self.regcond:
# Start all worker threads
self.logger.debug("adding %d threads to thread pool" % (
numthreads))
for i in range(numthreads):
t = self.workerClass(self.queue, logger=self.logger,
ev_quit=self.ev_quit, tpool=self.tpool,
**kwdargs)
self.workers.append(t)
t.start()
self.numthreads += numthreads
def stopall(self, wait=False):
"""Stop all threads in the worker pool. If _wait_ is True
then don't return until all threads are down.
"""
self.logger.debug("stopall called")
with self.regcond:
while self.status != 'up':
if self.status in ('stop', 'down') or self.ev_quit.isSet():
# For now, silently abandon additional request to stop
self.logger.warning("ignoring duplicate request to stop thread pool.")
return
self.logger.debug("waiting for threads: count=%d" % \
self.runningcount)
self.regcond.wait()
#assert(self.status == 'up')
self.logger.debug("stopping threads in thread pool")
self.status = 'stop'
# Signal to all threads to terminate.
self.ev_quit.set()
if wait:
# Threads are on the way down. Wait until last one quits.
while self.status != 'down':
self.logger.debug("waiting for threads: count=%d" % \
self.runningcount)
self.regcond.wait()
self.logger.debug("stopall done")
def workerStatus(self):
return list(map(lambda t: t.getstatus(), self.workers))
def addTask(self, task, priority=0):
"""Add a task to the queue of tasks.
The task will be executed in a worker thread as soon as one is available.
Tasks are executed in first-come-first-served order.
"""
self.queue.put((priority, task))
def delTask(self, taskid):
self.logger.error("delTask not yet implemented")
def purgeTasks(self):
self.logger.error("purgeTasks not yet implemented")
def register_up(self):
"""Called by WorkerThread objects to register themselves.
Acquire the condition variable for the WorkerThread objects.
Increment the running-thread count. If we are the last thread to
start, set status to 'up'. This allows startall() to complete
if it was called with wait=True.
"""
with self.regcond:
self.runningcount += 1
tid = thread.get_ident()
self.tids.append(tid)
self.logger.debug("register_up: (%d) count is %d" % \
(tid, self.runningcount))
if self.runningcount == self.numthreads:
self.status = 'up'
self.regcond.notify()
def register_dn(self):
"""Called by WorkerThread objects to register themselves.
Acquire the condition variable for the WorkerThread objects.
Decrement the running-thread count. If we are the last thread to
start, release the ThreadPool thread, which is stuck in start()
"""
with self.regcond:
self.runningcount -= 1
tid = thread.get_ident()
self.tids.remove(tid)
self.logger.debug("register_dn: count_dn is %d" % self.runningcount)
self.logger.debug("register_dn: remaining: %s" % str(self.tids))
if self.runningcount == 0:
self.status = 'down'
self.regcond.notify()
# ------------ SUPPORT FUNCTIONS ------------
_lock_seqnum = threading.Lock()
_count_seqnum = 0
def get_tag(taskParent):
global _count_seqnum
with _lock_seqnum:
generic_id = 'task%d' % (_count_seqnum)
_count_seqnum += 1
if taskParent:
tag = str(taskParent) + '.' + generic_id
else:
tag = generic_id
return tag
#END
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