Current File : //usr/lib/calibre/calibre/srv/pool.py
#!/usr/bin/env python3
__license__ = 'GPL v3'
__copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
import sys
from threading import Thread
from calibre.utils.monotonic import monotonic
from polyglot.queue import Queue, Full
class Worker(Thread):
daemon = True
def __init__(self, log, notify_server, num, request_queue, result_queue):
self.request_queue, self.result_queue = request_queue, result_queue
self.notify_server = notify_server
self.log = log
self.working = False
Thread.__init__(self, name='ServerWorker%d' % num)
def run(self):
while True:
x = self.request_queue.get()
if x is None:
break
job_id, func = x
self.working = True
try:
result = func()
except Exception:
self.handle_error(job_id) # must be a separate function to avoid reference cycles with sys.exc_info()
else:
self.result_queue.put((job_id, True, result))
finally:
self.working = False
try:
self.notify_server()
except Exception:
self.log.exception('ServerWorker failed to notify server on job completion')
def handle_error(self, job_id):
self.result_queue.put((job_id, False, sys.exc_info()))
class ThreadPool:
def __init__(self, log, notify_server, count=10, queue_size=1000):
self.request_queue, self.result_queue = Queue(queue_size), Queue(queue_size)
self.workers = [Worker(log, notify_server, i, self.request_queue, self.result_queue) for i in range(count)]
def start(self):
for w in self.workers:
w.start()
def put_nowait(self, job_id, func):
self.request_queue.put_nowait((job_id, func))
def get_nowait(self):
return self.result_queue.get_nowait()
def stop(self, wait_till):
for w in self.workers:
try:
self.request_queue.put_nowait(None)
except Full:
break
for w in self.workers:
now = monotonic()
if now >= wait_till:
break
w.join(wait_till - now)
self.workers = [w for w in self.workers if w.is_alive()]
@property
def busy(self):
return sum(int(w.working) for w in self.workers)
@property
def idle(self):
return sum(int(not w.working) for w in self.workers)
class PluginPool:
def __init__(self, loop, plugins):
self.workers = []
self.loop = loop
for plugin in plugins:
w = Thread(target=self.run_plugin, args=(plugin,), name=self.plugin_name(plugin))
w.daemon = True
w.plugin = plugin
self.workers.append(w)
def plugin_name(self, plugin):
return plugin.__class__.__name__
def run_plugin(self, plugin):
try:
plugin.start(self.loop)
except Exception:
self.loop.log.exception('Failed to start plugin:', self.plugin_name(plugin))
def start(self):
for w in self.workers:
w.start()
def stop(self, wait_till):
for w in self.workers:
if w.is_alive():
try:
w.plugin.stop()
except Exception:
self.loop.log.exception('Failed to stop plugin:', self.plugin_name(w.plugin))
for w in self.workers:
left = wait_till - monotonic()
if left > 0:
w.join(left)
else:
break
self.workers = [w for w in self.workers if w.is_alive()]
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