Scrapy`ReactorNotRestartable`:一个运行两个(或更多)蜘蛛的类

Question

我使用两阶段爬行将每日数据与Scrapy聚合在一起.第一阶段从索引页面生成URL列表,第二阶段将列表中每个URL的HTML写入Kafka主题.

尽管抓取的两个组件是相关的,但我希望它们是独立的:url_generator它将作为计划任务每​​天page_requester运行一次,并且会持续运行,在可用时处理URL.为了"礼貌",我将进行调整,DOWNLOAD_DELAY以便爬虫在24小时内完成,但对网站施加最小负荷.

我创建了一个CrawlerRunner类,它具有生成URL和检索HTML的功能:

from twisted.internet import reactor
from scrapy.crawler import Crawler
from scrapy import log, signals
from scrapy_somesite.spiders.create_urls_spider import CreateSomeSiteUrlList
from scrapy_somesite.spiders.crawl_urls_spider import SomeSiteRetrievePages
from scrapy.utils.project import get_project_settings
import os
import sys

class CrawlerRunner:

    def __init__(self):
        sys.path.append(os.path.join(os.path.curdir, "crawl/somesite"))
        os.environ['SCRAPY_SETTINGS_MODULE'] = 'scrapy_somesite.settings'
        self.settings = get_project_settings()
        log.start()

    def create_urls(self):
        spider = CreateSomeSiteUrlList()
        crawler_create_urls = Crawler(self.settings)
        crawler_create_urls.signals.connect(reactor.stop, signal=signals.spider_closed)
        crawler_create_urls.configure()
        crawler_create_urls.crawl(spider)
        crawler_create_urls.start()
        reactor.run()

    def crawl_urls(self):
        spider = SomeSiteRetrievePages()
        crawler_crawl_urls = Crawler(self.settings)
        crawler_crawl_urls.signals.connect(reactor.stop, signal=signals.spider_closed)
        crawler_crawl_urls.configure()
        crawler_crawl_urls.crawl(spider)
        crawler_crawl_urls.start()
        reactor.run()

当我实例化类时,我能够自己成功执行任一函数,但不幸的是,我无法一起执行它们:

from crawl.somesite import crawler_runner

cr = crawler_runner.CrawlerRunner()

cr.create_urls()
cr.crawl_urls()

第二个函数调用twisted.internet.error.ReactorNotRestartable在尝试reactor.run()在crawl_urls函数中执行时生成.

我想知道这个代码是否有一个简单的解决方法(例如,运行两个单独的Twisted反应堆的某种方式),或者是否有更好的方法来构建这个项目.

Answer 1

通过保持反应器打开直到所有蜘蛛都停止运行,可以在一个反应​​器内运行多个蜘蛛.这是通过保留所有正在运行的蜘蛛的列表而不是reactor.stop()在此列表为空之前执行来实现的:

import sys
import os
from scrapy.utils.project import get_project_settings
from scrapy_somesite.spiders.create_urls_spider import Spider1
from scrapy_somesite.spiders.crawl_urls_spider import Spider2

from scrapy import signals, log
from twisted.internet import reactor
from scrapy.crawler import Crawler

class CrawlRunner:

    def __init__(self):
        self.running_crawlers = []

    def spider_closing(self, spider):
        log.msg("Spider closed: %s" % spider, level=log.INFO)
        self.running_crawlers.remove(spider)
        if not self.running_crawlers:
            reactor.stop()

    def run(self):

        sys.path.append(os.path.join(os.path.curdir, "crawl/somesite"))
        os.environ['SCRAPY_SETTINGS_MODULE'] = 'scrapy_somesite.settings'
        settings = get_project_settings()
        log.start(loglevel=log.DEBUG)

        to_crawl = [Spider1, Spider2]

        for spider in to_crawl:

            crawler = Crawler(settings)
            crawler_obj = spider()
            self.running_crawlers.append(crawler_obj)

            crawler.signals.connect(self.spider_closing, signal=signals.spider_closed)
            crawler.configure()
            crawler.crawl(crawler_obj)
            crawler.start()

        reactor.run()

该类被执行:

from crawl.somesite.crawl import CrawlRunner

cr = CrawlRunner()
cr.run()

该解决方案基于Kiran Koduru的博客文章.