# Source code for scrapy.extensions.logstats

    import logging

    from twisted.internet import task

    from scrapy import signals
    from scrapy.exceptions import NotConfigured

    logger = logging.getLogger(__name__)

    class LogStats:
        """Log basic scraping stats periodically"""

        def __init__(self, stats, interval=60.0):
            self.stats = stats
            self.interval = interval
            self.multiplier = 60.0 / self.interval
            self.task = None

        @classmethod
        def from_crawler(cls, crawler):
            interval = crawler.settings.getfloat("LOGSTATS_INTERVAL")
            if not interval:
                raise NotConfigured
            o = cls(crawler.stats, interval)
            crawler.signals.connect(o.spider_opened, signal=signals.spider_opened)
            crawler.signals.connect(o.spider_closed, signal=signals.spider_closed)
            return o

        def spider_opened(self, spider):
            self.pagesprev = 0
            self.itemsprev = 0

            self.task = task.LoopingCall(self.log, spider)
            self.task.start(self.interval)

        def log(self, spider):
            items = self.stats.get_value("item_scraped_count", 0)
            pages = self.stats.get_value("response_received_count", 0)
            irate = (items - self.itemsprev) * self.multiplier
            prate = (pages - self.pagesprev) * self.multiplier
            self.pagesprev, self.itemsprev = pages, items

            msg = (
                "Crawled %(pages)d pages (at %(pagerate)d pages/min), "
                "scraped %(items)d items (at %(itemrate)d items/min)"
            )
            log_args = {
                "pages": pages,
                "pagerate": prate,
                "items": items,
                "itemrate": irate,
            }
            logger.info(msg, log_args, extra={"spider": spider})

        def spider_closed(self, spider, reason):
            if self.task and self.task.running:
                self.task.stop()