def open(self, spider):
self.spider = spider
self.queue = self.queue_cls(self.server, spider, self.queue_key)
self.df = RFPDupeFilter(self.server, self.dupefilter_key % {'spider': spider.name})
if self.idle_before_close < 0:
self.idle_before_close = 0
# notice if there are requests already in the queue to resume the crawl
if len(self.queue):
spider.log("Resuming crawl (%d requests scheduled)" % len(self.queue))
class Scheduler(object):
"""Redis-based scheduler"""
def __init__(self, server, persist, queue_key, queue_cls, dupefilter_key, idle_before_close):
"""Initialize scheduler.
Parameters
----------
server : Redis instance
persist : bool
queue_key : str
queue_cls : queue class
dupefilter_key : str
idle_before_close : int
"""
self.server = server
self.persist = persist
self.queue_key = queue_key
self.queue_cls = queue_cls
self.dupefilter_key = dupefilter_key
self.idle_before_close = idle_before_close
self.stats = None
def __len__(self):
return len(self.queue)
@classmethod
def from_settings(cls, settings):
server = r
persist = settings.get('SCHEDULER_PERSIST', SCHEDULER_PERSIST)
queue_key = settings.get('SCHEDULER_QUEUE_KEY', QUEUE_KEY)
queue_cls = load_object(settings.get('SCHEDULER_QUEUE_CLASS', QUEUE_CLASS))
dupefilter_key = settings.get('DUPEFILTER_KEY', DUPEFILTER_KEY)
idle_before_close = settings.get('SCHEDULER_IDLE_BEFORE_CLOSE', IDLE_BEFORE_CLOSE)
return cls(server, persist, queue_key, queue_cls, dupefilter_key, idle_before_close)
@classmethod
def from_crawler(cls, crawler):
instance = cls.from_settings(crawler.settings)
# FIXME: for now, stats are only supported from this constructor
instance.stats = crawler.stats
return instance
def open(self, spider):
self.spider = spider
self.queue = self.queue_cls(self.server, spider, self.queue_key)
self.df = RFPDupeFilter(self.server, self.dupefilter_key % {'spider': spider.name})
if self.idle_before_close < 0:
self.idle_before_close = 0
# notice if there are requests already in the queue to resume the crawl
if len(self.queue):
spider.log("Resuming crawl (%d requests scheduled)" % len(self.queue))
def close(self, reason):
if not self.persist:
self.df.clear()
self.queue.clear()
def enqueue_request(self, request):
if not request.dont_filter and self.df.request_seen(request):
return
if self.stats:
self.stats.inc_value('scheduler/enqueued/redis', spider=self.spider)
self.queue.push(request)
def next_request(self):
block_pop_timeout = self.idle_before_close
request = self.queue.pop(block_pop_timeout)
if request and self.stats:
self.stats.inc_value('scheduler/dequeued/redis', spider=self.spider)
return request
def has_pending_requests(self):
return len(self) > 0