一旦抓取了所有提供的网址，如何手动停止scrapy crawler？

Question

I have a implemented a crawler, which gets urls from text file and scrapes all the urls and then stops.

My implementation:

class CoreSpider(scrapy.Spider):
    name = "final"
    custom_settings = {
        'ROBOTSTXT_OBEY': 'False',
        'HTTPCACHE_ENABLED': 'True',
        'LOG_ENABLED': 'False',
        'DOWNLOADER_MIDDLEWARES': {
            'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware': 110,
            'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware': None,
            'random_useragent.RandomUserAgentMiddleware': 320
        },
    }

    def __init__(self):
        self.all_ngrams = get_ngrams()
        # logging.DEBUG(self.all_ngrams)
        self.search_term = ""
        self.start_urls = self.read_url()
        self.rules = (
            Rule(LinkExtractor(unique=True), callback='parse', follow=True, process_request='process_request'),
        )
 .....
 .....

I run this spider from script as below:

process = CrawlerProcess(get_project_settings())
process.crawl(CoreSpider)
process.start()

It gives error " twisted.internet.error.ReactorNotRestartable once it finished scraping all urls.

I tried using Runner like below implementation and it gives same error as previous.

runner = CrawlerRunner(get_project_settings())
d = runner.crawl(CoreSpider)
d.addBoth(lambda _: reactor.stop())
reactor.run() # the script will block here until the crawling is finished

Then I tried running spider like this :

runner = CrawlerRunner(get_project_settings())
@defer.inlineCallbacks
def crawl():
    yield runner.crawl(CoreSpider)
    reactor.stop()

crawl()
reactor.run()

But still it gives the same error.

How to manually stops the spiders, once all the urls has been scraped?

Update: Python 2.7 Stack Trace

Traceback (most recent call last):
  File "seed_list_generator.py", line 768, in <module>
    process = CrawlerProcess(get_project_settings())
  File "/root/anaconda2/lib/python2.7/site-packages/scrapy/crawler.py", line 243, in __init__
    super(CrawlerProcess, self).__init__(settings)
  File "/root/anaconda2/lib/python2.7/site-packages/scrapy/crawler.py", line 134, in __init__
    self.spider_loader = _get_spider_loader(settings)
  File "/root/anaconda2/lib/python2.7/site-packages/scrapy/crawler.py", line 330, in _get_spider_loader
    return loader_cls.from_settings(settings.frozencopy())
  File "/root/anaconda2/lib/python2.7/site-packages/scrapy/spiderloader.py", line 61, in from_settings
    return cls(settings)
  File "/root/anaconda2/lib/python2.7/site-packages/scrapy/spiderloader.py", line 25, in __init__
    self._load_all_spiders()
  File "/root/anaconda2/lib/python2.7/site-packages/scrapy/spiderloader.py", line 47, in _load_all_spiders
    for module in walk_modules(name):
  File "/root/anaconda2/lib/python2.7/site-packages/scrapy/utils/misc.py", line 71, in walk_modules
    submod = import_module(fullpath)
  File "/root/anaconda2/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/root/Public/company_profiler/profiler/spiders/run_spider.py", line 12, in <module>
    process.start()
  File "/root/anaconda2/lib/python2.7/site-packages/scrapy/crawler.py", line 285, in start
    reactor.run(installSignalHandlers=False)  # blocking call
  File "/root/anaconda2/lib/python2.7/site-packages/twisted/internet/base.py", line 1242, in run
    self.startRunning(installSignalHandlers=installSignalHandlers)
  File "/root/anaconda2/lib/python2.7/site-packages/twisted/internet/base.py", line 1222, in startRunning
    ReactorBase.startRunning(self)
  File "/root/anaconda2/lib/python2.7/site-packages/twisted/internet/base.py", line 730, in startRunning
    raise error.ReactorNotRestartable()
twisted.internet.error.ReactorNotRestartable

Python 3.6 Trace back:

 File "seed_list_generator.py", line 769, in <module>
    process = CrawlerProcess(get_project_settings())
  File "/root/anaconda3/lib/python3.6/site-packages/scrapy/crawler.py", line 249, in __init__
    super(CrawlerProcess, self).__init__(settings)
  File "/root/anaconda3/lib/python3.6/site-packages/scrapy/crawler.py", line 137, in __init__
    self.spider_loader = _get_spider_loader(settings)
  File "/root/anaconda3/lib/python3.6/site-packages/scrapy/crawler.py", line 336, in _get_spider_loader
    return loader_cls.from_settings(settings.frozencopy())
  File "/root/anaconda3/lib/python3.6/site-packages/scrapy/spiderloader.py", line 61, in from_settings
    return cls(settings)
  File "/root/anaconda3/lib/python3.6/site-packages/scrapy/spiderloader.py", line 25, in __init__
    self._load_all_spiders()
  File "/root/anaconda3/lib/python3.6/site-packages/scrapy/spiderloader.py", line 47, in _load_all_spiders
    for module in walk_modules(name):
  File "/root/anaconda3/lib/python3.6/site-packages/scrapy/utils/misc.py", line 71, in walk_modules
    submod = import_module(fullpath)
  File "/root/anaconda3/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 978, in _gcd_import
  File "<frozen importlib._bootstrap>", line 961, in _find_and_load
  File "<frozen importlib._bootstrap>", line 950, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 655, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 205, in _call_with_frames_removed
  File "/root/Public/company_profiler/profiler/spiders/run_spider.py", line 12, in <module>
    process.start()
  File "/root/anaconda3/lib/python3.6/site-packages/scrapy/crawler.py", line 291, in start
    reactor.run(installSignalHandlers=False)  # blocking call
  File "/root/anaconda3/lib/python3.6/site-packages/twisted/internet/base.py", line 1242, in run
    self.startRunning(installSignalHandlers=installSignalHandlers)
  File "/root/anaconda3/lib/python3.6/site-packages/twisted/internet/base.py", line 1222, in startRunning
    ReactorBase.startRunning(self)
  File "/root/anaconda3/lib/python3.6/site-packages/twisted/internet/base.py", line 730, in startRunning
    raise error.ReactorNotRestartable()
twisted.internet.error.ReactorNotRestartable

Thanks in advance.

Answer 1

What happens when you change your code like this?

class CoreSpider(scrapy.Spider):
    name = "final"
    custom_settings = {
        'ROBOTSTXT_OBEY': 'False',
        'HTTPCACHE_ENABLED': 'True',
        'LOG_ENABLED': 'False',
        'DOWNLOADER_MIDDLEWARES': {
            'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware': 110,
            'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware': None,
            'random_useragent.RandomUserAgentMiddleware': 320
        },
    }

    def __init__(self,*args,**kwargs):
        # python 3
        super().__init__(*args,**kwargs)
        # python 2
        # super(CoreSpider, self).__init__(*args, **kwargs)

        self.all_ngrams = get_ngrams()
        # logging.DEBUG(self.all_ngrams)
        self.search_term = ""
        self.start_urls = self.read_url()
        self.rules = (
            Rule(LinkExtractor(unique=True), callback='parse', follow=True, process_request='process_request'),
        )
 .....
 .....

Answer 2

Finally I managed to stop the crawler by putting it inside if __name__ == "__main__" block.

if __name__ == '__main__':
    process = CrawlerProcess(get_project_settings())
    process.crawl(CoreSpider)
    process.start()

It stops the crawler gracefully once it finishes scrapping all urls.